Rules and Regulations

for the
Construction and Classification
of Steel Ships

Part 2
Inspection and Testing of Materials

July 2021
 Indian Register of Shipping

Part 2

Inspection and Testing of Materials

Contents

Chapter 1 General Requirements

Chapter 2 Mechanical Testing Procedures

Chapter 3 Rolled Steel Plates, Strips, Sections and Bars

Chapter 4 Steel Castings

Chapter 5 Steel Forgings

Chapter 6 Steel Pipes and Tubes

Chapter 7 Iron Castings

Chapter 8 Copper Alloys

Chapter 9 Aluminium Alloys

Chapter 10 Equipment

Chapter 11 Approval of Welding Consumables for use in

Ship Construction
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Contents

Chapter 1 : General Requirements

Section 1 : Conditions for Manufacture, 1.9 Definitions

Survey and Certification
1.10 Retest procedures
1.1 Scope
1.11 Visual and non-destructive examination
1.2 Information to be supplied to the manufac-
turer 1.12 Rectification of defective material

1.3 Manufacture 1.13 Identification of materials

1.4 Survey procedure

Section 2 : Certification of Materials Based
1.5 Chemical composition on Alternative Certification Scheme

1.6 Heat treatment 2.1 General

1.7 Test material 2.2 Requirements for approval

1.8 Mechanical tests 2.3 Information required for approval

Chapter 2 : Mechanical Testing Procedures

Section 1 : General Requirements Section 3 : Impact Tests

1.1 General 3.1 Dimensions of test pieces

1.2 Selection of test samples 3.2 Testing procedure

1.3 Preparation of test specimens

Section 4 : Ductility Testing of Pipes and
1.4 Discarding of test specimens Tubes

4.1 Bend tests

Section 2 : Tensile Testing
4.2 Flattening tests
2.1 Dimensions of tensile test specimens
4.3 Drift expanding test
2.2 Fracture elongation
4.4 Flanging tests
2.3 Definition of yield stress
4.5 Ring expanding test
2.4 Procedure for tensile testing at ambient
temperature 4.6 Ring tensile test

2.5 Procedure for tensile testing at elevated

temperatures

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Section 5 : The Brittle Crack Arrest

Toughness Test Section 6 : Isothermal Crack Arrest
Temperature (CAT) Test
5.1 Scope
6.1 Scope
5.2 Symbols
6.2 Symbols
5.3 Testing Equipment
6.3 Testing equipment
5.4 Test Specimens
6.4 Test specimens
5.5 Test Methods
6.5 Test Method
5.6 Test Procedures
6.6 Measurements after test and test validation
judgement
5.7 Determination of arrest toughness

5.8 Reporting 6.7 Judgement of ‘arrest’ or ‘propagate’

6.8 Ttest, Tarrest and CAT determination

Appendix A : Method for obtaining Kca at a
6.9 Reporting
specific temperature and the evaluation
6.10 Use of test for material qualification testing

Appendix B : Double Tension Type Arrest Test

Chapter 3 : Rolled Steel Plates, Strips, Sections and Bars

Section 1 : General Requirements Section 2 : Normal Strength Steels for Ship

Structures
1.1 Scope
2.1 General
1.2 Manufacture
2.2 Approval
1.3 Quality of materials
2.3 Method of manufacture
1.4 Thickness tolerance of plates and wide flats
with width  600 [mm] 2.4 Chemical composition

2.5 Condition of supply

1.5 Heat treatment, condition of supply
2.6 Mechanical properties
1.6 Test material
2.7 Surface quality
1.7 Mechanical test specimens

1.8 Surface inspection and dimensions 2.8 Internal soundness

1.9 Freedom from defects 2.9 Tolerances

1.10 Special quality plate material (‘Z’ quality) 2.10 Identification of materials

1.11 Branding of materials 2.11 Testing and inspection

1.12 Test certificates or other documentation
2.12 Test materials

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2.13 Mechanical test specimens 4.6 Mechanical properties

2.14 Number of test specimens 4.7 Tolerances

4.8 Surface quality

2.15 Retest procedures
4.9 Internal soundness

Section 3 : Higher Strength Steels for Ship 4.10 Stress relieving heat treatment and other
Structures heat treatments

3.1 General 4.11 Facilities for inspection

3.2 Approval 4.12 Identification of materials

4.13 Branding
3.3 Method of manufacture
4.14 Documentation of inspection tests
3.4 Chemical composition

3.5 Condition of supply Section 5 : Steel for Low Temperature

Service
3.6 Mechanical properties
5.1 General
3.7 Surface of quality
5.2 Deoxidation and chemical composition
3.8 Internal Soundness
5.3 Heat treatment
3.9 Tolerances
5.4 Mechanical tests
3.10 Identification of Materials

3.11 Testing and Inspection Section 6 : Steels for Boilers and Pressure
Vessels
3.12 Test Material
6.1 General
3.13 Mechanical tests specimens
6.2 Deoxidation and chemical composition
3.14 Number of Test Specimens
6.3 Heat treatment, condition of supply
3.15 Manufacturing approval scheme for EH47
steels
6.4 Mechanical tests
3.16 Retest Procedures
6.5 Mechanical properties for design purposes
at elevated temperatures
Section 4 : High Strength Steels for Welded
Structures
Section 7 : Steels for Machinery Structures
4.1 General

4.2 Approval 7.1 General

4.3 Method of manufacture

Section 8 : Plates with Specified minimum
4.4 Chemical composition through Thickness Properties (‘Z’ Quality)

4.5 Delivery condition – Rolling process and 8.1 General

heat treatment

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8.2 Manufacture 9.4 Mechanical tests

8.3 Test material 9.5 Through thickness tests

8.4 Dimensions of through thickness tensile test 9.6 Intergranular corrosion tests
specimens
9.7 Dimensional tolerances
8.5 Mechanical tests
9.8 Clad plates
8.6 Non-destructive examination
9.9 Identification of materials

Section 9 : Austenitic and Duplex Stainless 9.10 Certification of materials

Steels

9.1 Scope Section 10 : Brittle Crack Arrest Steels

9.2 Chemical composition 10.1 General

9.3 Heat treatment 10.2 Manufacturing Approval Scheme

Chapter 4 : Steel Castings

Section 1 : General Requirements
2.5 Mechanical properties
1.1 Scope

1.2 Manufacture Section 3 : Ferritic Steel Castings for Low

Temperature Services
1.3 Quality of castings
3.1 General
1.4 Chemical composition
3.2 Chemical composition
1.5 Inspection
3.3 Heat treatment
1.6 Hydraulic pressure testing
3.4 Mechanical tests
1.7 Rectification of defective castings
3.5 Non-destructive testing
1.8 Identification of castings

1.9 Certification Section 4 : Steel Castings for Propellers

4.1 Scope
Section 2 : Hull and Machinery Steel
Castings for General Applications 4.2 Foundry Approval

2.1 Scope 4.3 Quality of castings

2.2 Chemical composition 4.4 Dimensions, dimensional and geometrical

tolerances
2.3 Heat treatment
4.5 Chemical Composition
2.4 Mechanical tests

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4.6 Heat treatment Section 5 : Austenitic Stainless Steel
Castings
4.7 Mechanical properties
5.1 Scope
4.8 Definition of skew, severity zones
5.2 Chemical composition
4.9 Non-destructive examination
5.3 Heat treatment
4.10 Acceptance criteria for liquid penetrant
testing and magnetic particle testing
5.4 Mechanical tests
4.11 Repair of defects
5.5 Intergranular corrosion tests
4.12 Welding repair procedure
5.6 Non-destructive examination
4.13 Identification and marking

4.14 Document and Certification Section 6 : Castings for other Applications

4.14 Welding procedure qualification test for 6.1 General

repair of cast steel propeller

Chapter 5 : Steel Forgings

Section 1 : General Requirements 2.3 Mechanical tests

1.1 Scope 2.4 Mechanical properties

1.2 Manufacture
Section 3 : Ferritic Steel Forgings for Low
1.3 Quality of forgings Temperature Service

1.4 Chemical composition 3.1 Scope

1.5 Heat treatment (including surface hardening 3.2 Chemical composition

and straightening)
3.3 Heat treatment
1.6 Mechanical tests
3.4 Mechanical tests
1.7 Inspection
3.5 Pressure tests
1.8 Rectification of defective forgings

1.9 Identification of forgings Section 4 : Austenitic Stainless Steel

Forgings
1.10 Certification

4.1 General
Section 2 : Hull and Machinery Steel
Forgings for General Applications 4.2 Mechanical properties for design purposes

2.1 Scope 4.3 Non-destructive examination

2.2 Chemical composition 4.4 Intergranular corrosion tests

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Chapter 6 : Steel Pipes and Tubes

Section 1 : General Requirements

3.5 Mechanical properties for design
1.1 Scope

1.2 Manufacture Section 4 : Boiler and Superheater Tubes

1.3 Quality 4.1 General

1.4 Chemical composition 4.2 Manufacture and chemical composition

1.5 Heat treatment 4.3 Heat treatment

1.6 Test material 4.4 Mechanical tests

1.7 Test specimens and testing procedures 4.5 Mechanical properties for design

1.8 Visual and non-destructive testing

Section 5 : Tubes and Pipes for Low
1.9 Hydraulic tests Temperature Services

1.10 Rectification of defects 5.1 Scope

1.11 Identification
5.2 Manufacture
1.12 Certification
5.3 Chemical composition

5.4 Heat treatment

Section 2 : Seamless Pressure Pipes
5.5 Mechanical tests
2.1 General

2.2 Manufacture and chemical composition Section 6 : Austenitic Stainless Steel

Pressure Pipes
2.3 Heat treatment

2.4 Mechanical tests 6.1 Scope

2.5 Mechanical properties for design 6.2 Manufacture and chemical composition

6.3 Heat treatment

Section 3 : Welded Pressure Pipes
6.4 Mechanical tests
3.1 General
6.5 Intergranular corrosion tests
3.2 Manufacture and chemical composition
6.6 Fabricated pipework
3.3 Heat treatment

3.4 Mechanical tests

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Chapter 7 : Iron Castings

Section 1 : General Requirements 1.7 Mechanical properties

1.1 Scope 1.8 Visual and non-destructive examination

1.2 Manufacture 1.9 Metallographic examination

1.3 Quality of castings 1.10 Rectification of defective castings

1.4 Chemical composition 1.11 Identification of castings

1.5 Heat treatment 1.12 Certification

1.6 Mechanical tests

Chapter 8 : Copper Alloys

Section 1 : General Requirements
3.4 Quality of castings
1.1 Scope
3.5 Dimensions, dimensional and geometrical
tolerances
Section 2 : Castings for Valves and Fittings
3.6 Chemical composition and metallurgical
2.1 Scope characteristics

2.2 Manufacture 3.7 Mechanical properties and tests

2.3 Quality of castings 3.8 Definition of skew, severity zones

2.4 Chemical composition 3.9 Non-destructive testing

2.5 Heat treatment 3.10 Acceptance criteria for liquid penetrant

testing
2.6 Mechanical tests
3.11 Repair of defects
2.7 Visual examination
3.12 Welding repair procedure
2.8 Pressure testing
3.13 Straightening
2.9 Rectification of defective castings
3.14 Identification and marking
2.10 Identification
3.15 Manufacturer’s Certificates
2.11 Certification 3.16 Welding procedure qualification tests for
repair of cast copper alloy propeller

Section 3 : Castings for Propellers

Section 4 : Tubes
3.1 Scope
4.1 Scope
3.2 Foundry approval
4.2 Manufacture
3.3 Moulding and casting

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4.3 Quality
4.8 Stress cracking test
4.4 Chemical composition
4.9 Hydraulic test
4.5 Heat treatment
4.10 Identification
4.6 Mechanical tests
4.11 Certification
4.7 Visual examination

Chapter 9 : Aluminium Alloys

Section 1 : General 2.18 Certification

1.1 Scope
Section 3 : Aluminium Alloy Castings

Section 2 : Wrought Aluminium Alloys 3.1 Scope

2.1 Scope 3.2 Manufacture

2.2 Manufacture 3.3 Quality of castings

2.3 Quality of materials 3.4 Chemical composition

2.4 Dimensional tolerances 3.5 Heat treatment

2.5 Chemical composition 3.6 Mechanical tests

2.6 Heat treatment 3.7 Visual examination

2.7 Test material 3.8 Rectification of defective castings

2.8 Testing and inspection 3.9 Pressure testing

2.9 Freedom from defects 3.10 Identification

2.10 Corrosion testing 3.11 Certification

2.11 Test materials

Section 4 : Aluminium/Steel Transition Joints
2.12 Mechanical test specimens
4.1 Scope
2.13 Number of test specimens
4.2 Manufacture
2.14 Retest procedures
4.3 Visual and non-destructive examination
2.15 Visual and non-destructive examination
4.4 Mechanical tests
2.16 Rectification of defects
4.5 Identification
2.17 Identification 4.6 Certification

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Chapter 10 : Equipment
Section 1 : Anchors
Section 4 : Steel Wire Ropes
1.1 Scope
4.1 General
1.2 Manufacture
4.2 Materials
1.3 Dimensions and tolerances
4.3 Zinc coating tests
1.4 Proof test of anchors
4.4 Test on completed ropes
1.5 Inspections and other tests
4.5 Identification
1.6 Identification

1.7 Painting Section 5 : Offshore Mooring Chains

5.1 Scope
Section 2 : Stud Link Chain Cables
5.2 Chain grades
2.1 Scope
5.3 Approval of chain manufacturers
2.2 Manufacture
5.4 Approval of quality system at chain and
accessory manufacturers
2.3 Design and tolerances
5.5 Approval of steel mills - rolled bar
2.4 Material for welded chain cables and
accessories
5.6 Approval of forge shops and foundries -
accessories
2.5 Material for cast chain cables and
accessories 5.7 Rolled steel bars

2.6 Material for forged chain cables and 5.8 Forged steel
accessories
5.9 Cast steel
2.7 Heat treatment of completed chain cables

2.8 Materials and welding of studs 5.10 Materials for studs

5.11 Design and manufacture

2.9 Testing of completed chain cables

2.10 Accessories for chain cables 5.12 Chain cable manufacturing process

2.11 Identification 5.13 Testing and inspection of finished chain

5.14 Testing and inspection of accessories

Section 3 : Short Link Chain Cables
5.15 Chafing chain for single point mooring
arrangements
3.1 General

3.2 Testing and inspection of chain cables

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Chapter 11 : Approval of Welding Consumables for Use in

Ship Construction

Section 1 : General Section 3 : Deep Penetration Electrodes for

Manual Welding
1.1 Scope
3.1 General
1.2 Manufacture
3.2 Deep penetration butt weld tests
1.3 Grading
3.3 Deep penetration fillet weld test
1.4 Approval procedure
3.4 Electrodes designed for gravity or contact
1.5 Test assemblies welding

1.6 Annual inspection and tests 3.5 Annual tests

1.7 Upgrading and uprating 3.6 Certification

1.8 Dimensions of test specimens

Section 4 : Wire-flux Combinations for
1.9 Testing procedures Submerged Arc Automatic Welding
1.10 Re-test procedures 4.1 General
1.11 Chemical composition 4.2 Multi-run technique

4.3 Deposited metal tests

Section 2 : Electrodes for Normal Penetra-
tion Manual Welding 4.4 Butt weld test (two-run technique)

2.1 General 4.5 Butt weld test (multi-run technique)

2.2 Deposited metal tests 4.6 Annual tests

2.3 Butt weld tests 4.7 Upgrading and uprating
2.4 Fillet weld tests
Section 5 : Wires and Wire-gas Combina-
2.5 Hydrogen test tions for Semi-automatic and Automatic
Welding
2.6 Covered electrodes for gravity or contact
welding 5.1 General
2.7 Annual tests 5.2 Approval tests for two-run automatic welding
2.8 Upgrading and uprating 5.3 Approval tests for semi-automatic multi-run
welding
2.9 Certification

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5.4 Approval tests for multi-run automatic
welding 7.3 Testing on welded joints

5.5 Annual tests 7.4 Hydrogen test

5.6 Upgrading and uprating 7.5 Annual tests

Section 6 : Consumables for use in Electro- Section 8 : Consumables for Welding of

slag and Electro-gas Vertical Welding Aluminium Alloys

6.1 General 8.1 General

6.2 Butt weld tests 8.2 Initial approval tests for manual, semi-
automatic and automatic multi-run techniques
6.3 Annual tests
8.3 Deposited metal test assemblies
6.4 Upgrading and uprating
8.4 Butt weld test assemblies

Section 7 : Welding Consumables for High 8.5 Fillet weld test assemblies
Strength Steels for Welded Structures
8.6 Initial approval tests for two-run technique
7.1 General
8.7 Annual tests
7.2 Testing of the weld metal

End of Contents

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Chapter 1

General Requirements

Contents
Section
1 Conditions for Manufacture, Survey and Certification
2 Certification of Materials Based on Alternative Certification Scheme

Section 1

Conditions for Manufacture, Survey and Certification

1.1 Scope 1.3.3 The manufacturer should demonstrate to

the satisfaction of IRS that necessary
1.1.1 Materials, used for the construction or manufacturing and testing facilities are available
repair of the hull and machinery of ships which and are supervised by qualified personnel.
are classed or intended to be classed with IRS,
are to be manufactured, tested and inspected in 1.3.4 Approval of manufacturers with respect to
accordance with the requirements of this Part. the materials and grades covered by this Part
will be considered by IRS on the basis of a
1.1.2 Materials complying with recognized detailed description of the manufacturing
national or international standards with process and inspection routines, results from
specifications equivalent to the requirements of testing of materials and a report made by IRS
this Part may be accepted. Surveyors confirming the information given by
the works and results.
1.2 Information to be supplied to the
manufacturer 1.3.5 Where the manufacturer has more than
one works, approval for individual works would
1.2.1 The ship or machinery builder is to provide be required.
the manufacturer with such information as is
necessary to ensure that inspection and testing 1.4 Survey procedure
can be carried out in accordance with these
Rules. 1.4.1 The Surveyors are to be allowed access to
all the relevant parts of the works and are to be
1.3 Manufacture provided with necessary facilities and
information to enable them to verify that
1.3.1 Materials used for the construction or manufacture is being carried out in accordance
repair of the hull and machinery of ships which with the approved procedure. Adequate facilities
are classed or intended to be classed with IRS are also to be provided for the selection of test
are to be made at works which have been materials, the witnessing of mechanical tests
approved by IRS for the type of the product and the examination of materials, as required by
being supplied. these Rules.

1.3.2 Where this part of the Rules requires 1.4.2 Prior to the submission of material for
materials or products to be manufactured at acceptance, manufacturers are to provide the
works approved by IRS, consideration may be Surveyors with details of the order specification
given by IRS for the acceptance of works and any special conditions additional to the Rule
approved by other IACS Member Societies. requirements.

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Chapter 1 Part 2
Page 2 of 5 General Requirements

1.4.3 Before final acceptance, all materials are components which require heat treatment,
to be submitted to specified tests and alternative methods will be specially considered.
examinations under conditions acceptable to the
Surveyors. The results are to comply with Rules 1.7 Test material
and all materials are to be to the satisfaction of
the Surveyors. 1.7.1 Sufficient test material is to be provided for
1.4.4 The specified tests and examinations are the preparation of the tests detailed in the
to be carried out prior to the dispatch of all specific requirements. It is, however, in the
finished materials from the manufacturer's interests of manufacturers to provide additional
works. Where materials are supplied in the material for any retests which may be
rough or unfinished condition, as many as necessary, as insufficient or unacceptable test
possible of the specified tests are to be carried material may be a cause for rejection.
out by the manufacturer and any tests or
examinations not completed are to be carried 1.7.2 The test material is to be representative of
out in consultation with the Surveyors, at a the item or batch and is not to be separated until
subsequent stage of manufacture. all the specified heat treatment has been
completed, except where provision for an
1.4.5 In the event of any material proving alternative procedure is made in the subsequent
unsatisfactory, during subsequent working, chapters of this Part.
machining or fabrication, it is to be rejected, not
withstanding any previous certification. In case of castings where separately cast test
samples are accepted, the test samples are to
1.5 Chemical composition be cooled down under the same conditions as
the castings.
1.5.1 The chemical composition of the ladle
samples is to be determined by the 1.7.3 All test material is to be selected by the
manufacturer in an adequately equipped and surveyor and identified by suitable markings
competently staffed laboratory. The which are to be maintained during the
manufacturer's analysis will be accepted, but preparation of the test specimen.
may be subject to occasional independent
checks if required by the Surveyors. 1.8 Mechanical tests

1.5.2 At the discretion of the Surveyors, a check 1.8.1 The number and direction of test
chemical analysis of suitable samples from specimens and their dimensions are to be in
products may also be required. These samples accordance with the requirements of
are to be taken from the material used for subsequent chapters of this Part and the
mechanical tests, but where this is not specific requirements for the product.
practicable an alternative procedure for
obtaining a representative sample is to be 1.8.2 Where Charpy impact tests are required, a
agreed with the manufacturer. set of three test specimens are to be prepared
and the average energy value is to comply with
1.6 Heat treatment the requirements of subsequent Chapters of this
part. One individual value may be less than the
1.6.1 Materials are to be supplied in the required average value provided that it is not
condition specified in, or permitted by the Rules. less than 70 per cent of that value.
Heat treatment is to be carried out in properly
constructed furnaces which are efficiently 1.8.3 Where metric or imperial units are to be
maintained and have adequate means for used for acceptance testing, the specified
control and recording of temperature. The values are to be converted in accordance with
furnace dimensions are to be such as to allow the appropriate conversions given in Table
the whole item to be uniformly heated to the 1.8.1.
necessary temperature. In the case of very large

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Table 1.8.1 : Conversion of SI units to metric

and imperial units
1 N/mm2 or Mpa = 0.102 kgf/mm2
1 N/mm2 or Mpa = 0.0647 tonf/in2
1 N/mm2 or Mpa = 0.145 x 103 lbf/in2
1J = 0.102 Kgf m
1J = 0.738 ft Ibs
1 Kgf/mm2 = 9.81 N/mm2 or MPa
1 tonf/in2 = 15.45 N/mm2 or MPa
1 Ibf/in2 = 6.89 x 10-3 MPa
1 kgf m = 9.81 J
1 ft lbf = 1.36 J

Notes :

The conversions may be rounded to the nearest multiples as follows :

1 For tensile strength values at ambient 1 Kgf/mm2

temperature 0.5 tonf/in2
1 x 103 lbf.in2
10N/mm2
2 For yield and proof stress values at 0.5 kgf/mm2
ambient temperature 0.2 tonf/in2
0.5 x 103 lbf/in2
5 N/mm2
3 For lower yield or proof stress values 0.1 kgf/mm2
at elevated temperatures and stress 0.05 tonf/in2
to rupture. 0.1 x 103 lbf/in2
1 N/mm2
4 For impact energy values 0.1 kgf m
1 ft lbf
1J

1.9 Definitions 1.10.2 Where the results from a set of three

impact test specimens do not comply with the
1.9.1 The following definitions are applicable to requirements, an additional set of three impact
this Part: test specimens may be tested provided that not
more than two individual values are less than
Item A single forging, casting, plate, tube or the required average value and, of these, not
other rolled product as delivered. more than one is less than 70 per cent of this
average value. The results obtained are to be
Piece The rolled product from a single slab or combined with the original results to form a new
billet or from a single ingot if this is rolled directly average which, for acceptance, is not to be less
into plates, strips, sections or bars. than the required average value. Additionally, for
these combined results, not more than two
Batch A number of similar items or pieces individual values are to be less than the required
presented as a group for acceptance testing. average value and, of these, not more than one
is to be less than 70 per cent of this average
1.10 Retest procedures value.

1.10.1 Where the result of any test, other than 1.10.3 The additional tests detailed in 1.10.1
an impact test, does not comply with the and 1.10.2 are, where possible, to be taken from
requirements, two additional tests of the same material adjacent to the original tests. For
type may be taken. For acceptance of the castings, however, where insufficient material
material satisfactory results are to be obtained remains in the original test samples, the
from both of these tests. additional tests may be prepared from other test
samples representative of the castings.

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Chapter 1 Part 2
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1.10.4 When unsatisfactory results are obtained and the rectification has been completed in
from tests representative of a batch of material, accordance with applicable requirements of
the item or piece from which the tests were subsequent chapters of this Part and to the
taken is to be rejected. The remainder of the satisfaction of Surveyors.
batch may be accepted provided that two further
items or pieces are selected and tested with 1.12.2 The repair of defects by welding can be
satisfactory results. If the tests from one or both accepted only when permitted by the
of these additional items or pieces give appropriate specific requirements and provided
unsatisfactory results, the batch is to be that the agreement of the Surveyor is obtained
rejected. before the work is commenced. When a repair
has been agreed, it is necessary in all cases to
1.10.5 When a batch is rejected, the remaining prove by suitable methods of non-destructive
items or pieces in the batch may be re- examination that the defects have been
submitted individually for test, and those which completely removed before welding is
give satisfactory results may be considered for commenced. Welding procedures and
acceptance by the Surveyors. inspection on completion of the repair are to be
in accordance with the appropriate specific
1.10.6 At the option of the manufacturer, requirement and are to be to the satisfaction of
rejected material may be re-submitted as the Surveyor.
another grade and may then be considered for
acceptance by the Surveyors, provided that the 1.13 Identification of materials
test results comply with the appropriate
requirements. 1.13.1 The manufacturer is to adopt a system of
identification which will enable all finished
1.10.7 When material which is intended to be material to be traced to the original cast, and the
supplied in the ''as rolled" or "hot finished" Surveyors are to be given all facilities for so
condition fails test, it may be suitably heat tracing the material when required. When any
treated and re-submitted for test, with the prior item has been identified by the personal mark of
concurrence of the ship or machinery builder. a Surveyor, or his deputy, this is not to be
Similarly materials supplied in the heat-treated removed until an acceptable new identification
condition may be re-heat treated and re- mark has been made. Failure to comply with this
submitted for test. condition will render the item liable to rejection.

1.11 Visual and non-destructive examination 1.13.2 Before any item is finally accepted it is to
be clearly marked by the manufacturer in at
1.11.1 Prior to the final acceptance of materials, least one place with the particulars detailed in
surface inspection, verification of dimensions the appropriate specific requirements.
and non-destructive examination are to be
carried out in accordance with the requirements 1.13.3 Hard stamping is to be used except
detailed in subsequent chapters of this Part. where this may be detrimental to the material, in
which case stenciling, painting or electric
1.11.2 When there is visible evidence to doubt etching is to be used. Paints used to identify
the soundness of any material or component, alloy steels are to be free from lead, copper,
such as flaws in test specimens or suspicious zinc or tin, i.e., the dried film is not to contain
surface marks, the manufacturer is expected to any of these elements in quantities more than
prove the quality of the material by any 250 ppm.
acceptable method.
1.13.4 Where a number of identical items are
1.12 Rectification of defective material securely fastened together in bundles, the
manufacturer need only brand the top of each
1.12.1 Small surface imperfections may be bundle. Alternatively a durable label giving the
removed by mechanical means provided that, required particulars may be attached to each
after such treatment, the dimensions are bundle.
acceptable, the area is proved free from defects

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Section 2

Certification of Materials Based on Alternative Certification Scheme

2.1 General 2.3.3 An outline description of all important

manufacturing plant and equipments. This is to
2.1.1 Alternative procedures for survey and include a production flow chart indicating all
testing may be accepted by IRS at works where stages where testing and inspection are carried
materials are manufactured under closely out along with details of equipments used for
control rolled conditions by semi-continuous or measuring and testing.
continuous processes under the Alternative
Certification Scheme (ACS), as detailed in 2.3.4 The system used for the identification and
Part1, Chapter 1, Section 4 of the Rules. traceability of raw materials, semi-finished and
finished Products.
2.1.2 Where it is considered that compliance
with Rule requirements can be satisfactorily 2.3.5 Information on the system of procurement
achieved, IRS will issue a Quality Assurance and acceptance of materials e.g. ingots, billets
Approval Certificate, based on the ACS to the or blooms for further processing where the
manufacturer. manufacturer does not produce such raw
materials.
2.1.3 The quality system procedures and
practices of a manufacturer who has been 2.3.6 Consolidated test results, physical,
granted approval will be kept under continuous chemical, non-destructive tests etc. for a period
review and audited as per the ACS. of preceding three months of products, if
possible, covering the full range of thickness,
2.2 Requirements for approval weight range and grades for which approval is
sought. The data is to include the number of
2.2.1 The conditions for approval are broadly samples, minimum, maximum, average value
outlined in Pt.1, Ch.1, Sec. 4, Cl. 4.3 of the and standard deviation. For high strength ship
Rules. steels, the carbon equivalent values are also
required. The data is to also include numbers of
2.3 Information required for approval rejections during manufacture as well as after
delivery and reasons thereof.
2.3.1 Manufacturers applying for approval under
this scheme are to submit the information 2.4 Assessment and approval, maintenance of
required by 2.3.2 to 2.3.6, in addition to the approval and certification of products would be
requirements of the ACS (Pt.1, Ch.1, Sec. 4, Cl. generally based on the ACS detailed in Pt.1,
4.4). Ch.1, Sec.4 of the Rules.

2.3.2 A detailed specification for each product.

End of Chapter

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Chapter 2

Mechanical Testing Procedures

Contents
Section
1 General Requirements
2 Tensile Testing
3 Impact Tests
4 Ductility Testing of Pipes and Tubes
5 The Brittle Crack Arrest Toughness Test
6 Isothermal Crack Arrest Temperature (CAT) Test

Section 1

General Requirements

1.1 General from the same cast and in the same condition of
heat treatment.
1.1.1 All tests are to be carried out by competent
personnel. The machines are to be maintained in 1.3 Preparation of test specimens
satisfactory and accurate condition and are to be
recalibrated at approximately annual intervals. 1.3.1 If test samples are cut from material by
This calibration is to be carried out by a nationally flame cutting or shearing, a reasonable margin is
recognized Authority or other organization of required to enable sufficient material to be
standing and is to be carried out to the removed from the cut edges during final
satisfaction of Surveyors. The accuracy of test machining.
machines is to be within  one per cent. A record
of all calibrations is to be kept available in the test 1.3.2 Test specimens are to be cut and prepared
house. in a manner which does not affect their
properties, i.e. not subjected to any significant
Testing machines are to be calibrated in cold straining or heating.
accordance with the following or other equivalent
recognized standards: 1.3.3 Where possible, test specimens from rolled
materials are to retain their rolled surface on both
a) Tensile / compression testing : ISO 7500-1 sides.
b) Impact testing : ISO 148-2
1.4 Discarding of test specimens
1.2 Selection of test samples
1.4.1 If a test specimen fails because of faulty
1.2.1 Test samples are to be selected by the manufacture, visible defects, or incorrect
Surveyor unless otherwise agreed. operation of the testing machine, it may be
discarded at the Surveyor's discretion and
1.2.2 All materials in a batch presented for testing replaced by a new test specimen prepared from
are to be of the same product form (e.g. plates, material adjacent to the original test.
sections, bars). Normally, the materials are to be

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Section 2

Tensile Testing

2.1 Dimensions of tensile test specimens - Round test specimens;

2.1.1 Generally, proportional test specimens with - Flat test specimens; and
a gauge length of 5.65So (where So is the cross-
sectional area of the test length) are to be used. - Full cross-section test specimens.
Where it is not possible to use such specimens,
non-proportional specimens may be considered. See also Fig.2.1.1.

2.1.2 For the purpose of determining the different

parameters related to tensile testing, three
different types of test specimens may be used :

2.1.2.1 The following symbols have been used in

the figure and in subsequent paragraphs:- 2.1.2.2 The gauge length may be rounded off to
the nearest 5 [mm] provided that the difference
d =diameter between this length and Lo is less than 10% of
a =thickness of specimen Lo.
b =width
Lo = Original gauge length 2.1.2.3 For plates with thickness equal to and
Lc = Parallel length greater than 3 [mm], test specimen according to
So = Original cross-sectional area alternatives A or B given below are to be used.
R = Transition radius Where the capacity of the available testing
D =External tube diameter machine is insufficient to allow the use of a test
t = plate thickness

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specimen of full thickness, this may be reduced 2.1.2.6 Wires: Full cross sectional test specimen
by machining one of the rolled surfaces. with the following dimensions is to be used:

Alternatively for materials over 40 [mm] thick, Lo =200 [mm]

proportional round test specimens with Lc =Lo + 50 [mm].
dimensions as specified in C below may be used.

Alternative A, Non-proportional flat test specimen 2.1.2.7 For forgings, castings (excluding grey
cast iron) and bars round test specimens with
a=t dimensions as specified in alternative C of 2.1.2.3
b =25 [mm] are usually to be used.
Lo =200 [mm]
Lc  212.5 [mm] 2.1.2.8 If for special reasons, other dimensions
R =25 [mm] are to be used, they will have to conform with the
following geometric relationship:
Alternative B, Proportional flat test specimen
Lo =5d;
a=t Lc =Lo + d:

b =25 [mm]
R=10 [mm], except for materials with a specified
Lo = 5.65 So minimum elongation A  10 per cent, where R is
to be 1.5 x d.
Lc Lo + 2 So
2.1.2.9 For tubes, test specimen according to
R =25 [mm] alternative A or B below are to be used:

Alternative C, round test specimen Alternative A :- Full cross-section test specimens

with plugged ends -
d =14 [mm] in general, but in no case less than Lo = 5.65 So
10 mm nor more than 20 [mm].

Lo = 5d [mm Lc  Lo + D/2

Lc  Lo + d/2 [mm] Lc is the distance between the grips or the plugs,

whichever is smaller.
R =10 [mm], in general
 1.5 d [mm], for nodular cast iron and
materials with a specified elongation of less than Alternative B :- Strip
10%. a =wall thickness of tube
b  12 [mm]
2.1.2.4 The round test specimen is to be located Lo = 5.65 So
with its center t/4 from the plate surface or as Lc = Lo + 2b
close to this position as possible.
The parallel test length is not to be flattened. but
2.1.2.5 For sheets and strips with thickness less the enlarged ends may be flattened for gripping
than 3 [mm] in the testing machine.

a=t Round test specimens may also be used

b =12.5 [mm] provided that the wall thickness is sufficient to
Lo =50 [mm] allow the machining of such specimens to the
Lc 75 [mm] dimensions in alternative C in 2.1.2.3 above with
their axes located at the midwall thickness.
R =25 [mm]

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2.1.2.10 The above is subject to any specific where,

dimensions or minimum cross-sectional area
requirements, with respect to test specimens, Ao = Required elongation for the non-
given in any subsequent Chapters of this Part. proportional test specimen
As = Specified elongation on a gauge length
2.1.2.11 Tensile test specimens for grey cast iron
of 5.65So
are to be machined to the dimensions shown in
Fig.2.1.2. Usually test specimens are machined So = Cross-sectional area of test specimen
from separately cast standard test coupons with Lo = Gauge length of test specimen.
30 [mm] diameter.
2.3 Definition of yield stress

2.3.1 The yield phenomenon is not exhibited by

all the steels detailed in this Part but, for
simplification the term "Yield Stress" is used
throughout when requirements are specified for
acceptance testing at ambient temperature.

2.3.2 Where reference is made to "Yield Stress"

in the requirements for carbon, carbon-
manganese and alloy steel products and in the
requirements for the approval of welding
consumables, either the upper yield stress or the
0.2 per cent proof stress under load is to be
determined.

2.1.2.12 The tolerances on specimen dimensions 2.3.3 For austenitic and duplex stainless steel
are to be in accordance with ISO 6892-98 or products and welding consumables, both the 0.2
other recognised standards as appropriate. per cent and 1.0 per cent proof stresses are to be
determined.
2.2 Fracture elongation
2.4 Procedure for tensile testing at ambient
2.2.1 Unless otherwise specified, the elongation temperature
values in this part correspond to those required
for proportional test specimens over a gauge 2.4.1 Unless otherwise specified, the test is to be
length 5.65 So. carried out at ambient temperature between 100C
and 350C.
If any part of the fracture takes place outside of
the middle one-third of the original gauge length, 2.4.2 Yield stress (Yield point) is to be taken as
the elongation value obtained may not be the value of stress measured at the
representative of the material. In such cases if the commencement of plastic deformation at yield or
elongation measured is less than the minimum the value of the stress measured at the first peak
requirements, the test result may be discarded obtained during yielding even when the peak is
and a retest carried out. equal to or less than any subsequent peaks
observed during plastic deformation at yield. The
2.2.2 If the material is ferritic steel of low or tensile test is to be carried out with an elastic
medium strength and not cold worked the stress rate within the limits indicated in Table
elongation may also be measured on a non- 2.4.2.
proportional gauge length after agreement with
IRS. Table 2.4.2

In that case the elongation required is to be Modulus of Rate of stressing

calculated from the following formula: elasticity of the [N/mm2] per second
material (E) Min. Max.
[N/mm2]
0.4
 So  < 150 000 2 20
Ao  2 x As    150 000 6 60
 L o 

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2.4.3 After reaching the yield or proof load, the from which 0.2 or 1.0 per cent proof stress can be
straining rate may be increased to a maximum of calculated.
0.008 per second for the determination of tensile
strength. 2.5 Procedure for tensile testing at elevated
temperatures
2.4.4 For steel, the upper yield stress is to be
calculated from : 2.5.1 The test specimens used for the
determination of lower yield or 0.2 per cent proof
a) the load immediately prior to a distinct drop stress at elevated temperatures are to have an
in the testing machine lever; or extensometer gauge length of not less than 50
[mm] and a cross sectional area of not less than
b) the load immediately prior to a fall back in the 65 [mm2]. Where, however, this is precluded by
movement of the pointer or the load at a the dimensions of the product or by the test
marked hesitation of this pointer; or equipment available, the test specimen is to be of
the largest practical dimensions.
c) a load/extension diagram using the value of
load measured either at the commencement 2.5.2 The heating apparatus is to be such that the
of plastic deformation or yield or at the first temperature of the specimen during testing does
peak obtained during yielding even when that not deviate from that specified by more than 
peak is equal to or less than any subsequent 5°C.
peaks observed.
2.5.3 The straining rate when approaching the
2.4.5 The 0.2 or 1.0 per cent proof stress (non- lower yield or proof load is to be controlled within
proportional elongation) is to be determined from the range 0.1 to 0.3 per cent of the extensometer
an accurate load/extension diagram by drawing a gauge length per minute.
line parallel to the straight elastic portion and
distant from it by an amount representing 0.2 or 2.5.4 The time intervals used for estimation of
1.0 per cent of extensometer gauge length. The strain rate from measurements of strain are not
point of intersection of this line with the plastic to exceed 6 seconds.
portion of the diagram represents the proof load,

Section 3

Impact Tests

3.1 Dimensions of test pieces

3.1.2 For material under 10 [mm] in thickness the
3.1.1 Impact tests are to be of either the charpy largest possible size of standard subsidiary
V-notch or the charpy U-notch type as required charpy V-notch is to be prepared with the notch
by the subsequent Chapters. The test specimens cut in the narrow face. Generally, impact tests are
are to be machined to the dimensions and not required when the thickness of material is
tolerances given in Table 3.1.1 and Table 3.1.2 less than 5 [mm] (less than 6 [mm] for pipes and
and are to be carefully checked for dimensional tubes).
accuracy.

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Table 3.1.1 : Dimensions and tolerances for charpy V-notch impact test specimens

Dimensions Nominal Tolerance

Length [mm] 55  0.60
Width [mm]
- standard specimen 10  0.11
- subsize specimen 7.5  0.11
- subsize specimen 5  0.06
Thickness [mm] 10  0.06
Angle of notch 45o  2
Depth below notch [mm] 8  0.06
Root radius [mm] 0.25  0.025
Distance of notch from end of specimen [mm] 27.5  0.42
Angle between plane of symmetry of notch and 90o  2
longitudinal axis of test specimen
Ref. Fig.3.1.1

Fig.3.1.1

Table 3.1.2 : Dimensions and tolerances for charpy U-notch impact test specimens

Dimensions Nominal Tolerance

Length [mm] 55  0.60
Width [mm] 10  0.11
Thickness [mm] 10  0.11
Depth of notch [mm] 5  0.09
Root radius [mm] 1  0.07
Distance of notch from end of test specimen [mm] 27.5  0.42
Angle between plane of symmetry of notch and longitudinal axis of
90  2
test specimen
Ref. Fig.3.1.1

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3.2 Testing procedure V- notch impact tests may be carried out at
ambient or lower temperatures in accordance
3.2.1 All impact tests are to be carried out on with specific requirements given in subsequent
Charpy machines having a striking energy of not Chapters. Where the test temperature is other
less than 150J and complying with following than ambient, the temperature of the test
requirements:- specimen is to be controlled to within  2°C for
sufficient time to ensure uniformity throughout the
a) Distance between supports 40 + 5 [mm] cross section of the test specimen, and suitable
-0 precautions are to be taken to prevent any
b) Radius of curvature of significant change in temperature during the
supports 1 -1.5 [mm] actual test. In cases of dispute, ambient
c) Taper of supports 1 in 5 temperature is to be considered as 18°C -27°C.

d) Angle at tip of hammer 30  1° 3.2.3 When reporting results, the units used for
expressing the energy absorbed and the testing
e) Radius of curvature of 1.0 -2.5 [mm] temperature are to be clearly stated. It is
hammer preferred that energy values for both charpy V-
notch and charpy U-notch impact tests be
f) Speed of hammer at the expressed in Joules and not [J/cm2].
instant of striking 4.5 - 7 [m/sec].
3.2.4 The minimum average values for
specimens are as given in Table 3.2.4.
3.2.2 Charpy U-notch impact tests are generally
to be carried out at ambient temperature. Charpy

Table 3.2.4

Charpy V-notch specimen size Minimum energy, average of 3-specimens

10 mm x 10 mm E
10 mm x 7.5 mm 5E/6
10 mm x 5.0 mm 2E/3
Notes:

E = the values of energy specified for full thickness 10 mm x 10 mm specimens

All other dimensions and tolerances are to be as specified in Table 3.1.1.
Only one individual value may be below the specified average value provided it is not less than 70%
of that value.
In all cases, the largest size Charpy specimens possible for the material thickness shall be
machined

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Section 4

Ductility Testing of Pipes and Tubes

4.1 Bend tests C = a constant dependent on the steel type and

detailed in the specific requirements.
4.1.1 The test specimens are to be cut as circum-
ferential strips of full wall thickness and with a After flattening, the specimens are to be free from
width of not less than 40 [mm]. For thick walled cracks or other flaws. Small cracks at the ends of
pipes, the thickness of the test specimens may the test specimens may be disregarded.
be reduced to 20 [mm] by machining. The edges
of specimen may be rounded to a radius of 1.6 4.2.3 For welded pipes or tubes, the weld is to be
[mm]. placed at an angle of 90° to the direction of the
pressure.
4.1.2 Testing is to be carried out at ambient
temperature, and the specimens are to be 4.3 Drift expanding test
doubled over, in the direction of the original
curvature, around a former. The diameter of the 4.3.1 The test specimens are to be cut with the
former is to be in accordance with the specific ends perpendicular to the axis of the tube. The
requirements for the material. The test is to be edges of the end to be tested may be rounded by
considered satisfactory if, after bending, the filing.
specimens are free from cracks and laminations.
Small cracks at the edges of the test specimen Metallic tubes: The length 'L' equal to twice the
are to be disregarded. external diameter 'D' of the tube if the angle of the
drift is 30° and L equal to 1.5D if the angle of the
4.2 Flattening tests drift is 45° or 60°. (Reference ISO 8493). The
test piece may be shorter if after testing the
4.2.1 The test specimens are to be cut with the remaining cylindrical portion is not less than 0.5D.
ends perpendicular to the axis of the pipe or tube.
The length of the specimen is to be not less than The rate of penetration of the mandrel is not to
10 [mm] or greater than 100 [mm]. exceed 50 [mm]/minute.

4.2.2 Testing is to be carried out at ambient 4.3.2 Testing is to be carried out at ambient
temperature and is to consist of flattening the temperature and is to consist of expanding the
specimens in a direction perpendicular to the end of the tube symmetrically by means of a
longitudinal axis of the pipe. (Reference is made hardened conical steel mandrel having a total
to ISO 8492). Flattening is to be carried out included angle of 45° or 60°. The mandrel is to be
between two plain parallel and rigid platens which forced into the test specimen until the percentage
extend over both the full length and width after increase in the outside diameter of the end of the
flattening of the test specimen. Flattening is to be test specimen is not less than the value given in
continued until the distance between the platens, the specific requirements for boiler and
measured under load, is not greater than the superheater tubes. The mandrel is to be
value given by the formula:- lubricated, but there is to be no rotation of the
tube or mandrel during the test. The expanded
t (1  C) portion of the tube is to be free from cracks or
H other flaws.
t
C
D 4.4 Flanging tests

where, 4.4.1 The test specimens are to be cut with the

ends perpendicular to the axis of the tube. The
H = distance between platens [mm]; length of the specimens is to be approximately
1.5D. The length may be shorter provided that
t = specified thickness of the pipe [mm]; after testing the remaining cylindrical portion is
not less than O.5D (Reference ISO 8494). The
D = Specified outside diameter [mm]; edges of the end to be tested may be rounded by
filing. The rate of penetration shall not exceed 50
[mm]/minute.

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4.4.2 Testing is to be carried out at ambient flanged portion of the tube is to be free from
temperature and is to consist of flanging the end cracks or other flaws.
of the tube symmetrically by means of hardened
conical steel mandrels. 4.5 Ring expanding test

4.4.3 The first stage of flanging is to be carried 4.5.1 The test piece consists of a ring having a
out with a conical angled mandrel having an length of between 10 to 16 [mm]. (Reference ISO
included angle of approximately 90° (See 8495). The rate of penetration of the mandrel is
Fig.4.4.3(a)) The completion of the test is not to exceed 30 [mm]/second.
achieved with a second forming tool as shown in
Fig.4.4.3(b). The mandrels are to be lubricated 4.6 Ring tensile test
and there is to be no rotation of the tube or
mandrels during the test. The test is to continue 4.6.1 The ring is to have a length of about 15
until the drifted portion has formed a flange [mm] with plain and smoothed ends cut
perpendicular to the axis of the test specimens. perpendicular to the tube axis. The ring is to be
The percentage increase in the external diameter drawn to fracture by means of two mandrels
of the end of specimens is not to be less than the placed inside the ring and pulled in tensile testing
value given in the specific requirements for boiler machine. The rate shall not exceed 5
and superheater tubes. The cylindrical and [mm]/second. (Reference ISO 8496).

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Section 5

The Brittle Crack Arrest Toughness Test

5.1 Scope
Using the stress intensity factor, calculate the
5.1.1 This Section is applicable to hull structural brittle crack arrest toughness, Kca, from the
steels with the thickness over 50 [mm] and not applied stress and the arrest crack length. This
greater than 100 [mm] specified in Chapter 3. value is the brittle crack arrest toughness at the
This Section specifies the test method for brittle temperature of the point of crack arrest (arrest
crack arrest toughness (i.e. Kca) of steel using temperature).
fracture mechanics parameter. The purpose of
this test is to assess brittle crack arrest toughness To obtain Kca at a specific temperature followed
with temperature gradient and to obtain the by the necessary evaluation, the method
corresponding brittle crack arrest toughness specified in Appendix A to this Section may be
value Kca. used.

5.1.2 The test envisages the following: As a method for initiating a brittle crack, a
secondary loading mechanism can also be used
- setting a temperature gradient in the width (see Appendix B to this Section “Double tension
direction of a test specimen type arrest test”).
- applying uniform stress to the test specimen
- striking the test specimen to initiate a brittle 5.2 Symbols
crack from the mechanical notch at the side of the
test specimen and cause crack arrest
(temperature gradient type arrest testing).

Table 5.2: Symbols used and their meanings

Symbol Unit Significance

a mm Crack length or arrest crack length
E N/mm2 Modulus of longitudinal elasticity
Ei J Impact energy
Es J Strain energy stored in a test specimen
Et J Total strain energy stored in tab plates and pin chucks
F MN Applied load
K N/mm3/2 Stress intensity factor
Kca N/mm3/2 Arrest toughness
L mm Test specimen length
Lp mm Distance between the loading pins
Lpc mm Pin chuck length
Ltb mm Tab plate length
T C Temperature or arrest temperature
t mm Test specimen thickness
ttb mm Tab plate thickness
tpc mm Pin chuck thickness
W mm Test specimen width
Wtb mm Tab plate width

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Table 5.2 : (Contd.)

Symbol Unit Significance

Wpc mm Pin chuck width
xa mm Coordinate of a main crack tip in the width direction
xbr mm Coordinate of the longest branch crack tip in the width direction
ya mm Coordinate of a main crack tip in the stress loading direction
Coordinate of the longest branch crack tip in the stress loading
ybr mm
direction
 N/mm2 Applied stress
Y0 N/mm2 Yield stress at room temperature

5.3 Testing Equipment propagation, the validity of the test results is

determined by the judgment method described in
The testing machine is used to apply tensile force 5.7.1.
to an integrated specimen, and impact equipment
is used to generate a brittle crack on the test 5.3.2 Impact Equipment
specimen.
5.3.2.1 Impact Methods
5.3.1 Testing Machine
.1 Methods to apply an impact load to an
5.3.1.1 Loading Method integrated specimen may be of a drop weight
type or of an air gun type.
.1 Tensile load to an integrated specimen is to be
hydraulically applied. The loading method to an .2 The wedge is to be hard enough to prevent
integrated specimen using the testing machine is significant plastic deformation caused by the
to be of a pin type. The stress distribution in the impact. The wedge thickness is to be equal to or
plate width direction is to be made uniform by greater than that of the test specimen, and the
aligning the centres of the loading pins of both wedge angle is to be greater than that of the
sides and the neutral axis of the integrated notch formed in the test specimen and have a
specimen. shape capable of opening up the notch of the test
specimen.
5.3.1.2 Loading Directions
5.4 Test Specimens
.1 The loading directions are to be either vertical
or horizontal. In the case of the horizontal 5.4.1 Test specimen shapes
direction, test specimen surfaces are to be placed
perpendicular to the ground. 5.4.1.1 The standard test specimen shape is
shown in Fig. 5.4.1.1. Table 5.4.1.1 specifies the
5.3.1.3 Distance between the loading pins ranges of test specimen thicknesses, widths and
width-to-thickness ratios.
.1 The distance between the loading pins is to be
approximately 3.4W or more, where W is the 5.4.1.2 In general, the test specimen length is to
width of the test specimen. Since the distance be, equal to or greater than its width.
between the loading pins sometimes has an
effect on the load drop associated with crack

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Fig. 5.4.1.1: Standard test specimen shape

Table 5.4.1.1: Dimensions of test specimens

Test specimen thickness, t 50 mm ≤ t ≤ 100 mm

350 mm ≤ W ≤ 1000 mm
Test specimen width, W
(Standard width: W = 500 mm)
Test specimen width/test specimen thickness, W/t W/t ≥ 5

5.4.2 Shapes of tab plates and pin chucks

5.4.2.1 The definitions of the dimensions of the

tab plates and pin chucks are shown in Fig.5.4.2
Typical examples are shown in Fig. 5.4.2.1.

Pin chuck (Thickness: tpc)

Tab plate Specimen

Wpc Wtb W
(Thickness: ttb) (Thickness: t)

Lpc Ltb L
Lp

(a) Single pin type

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Pin chuck (Thickness: tpc)

Tab plate Specimen

Wpc Wtb (Thickness: t ) (Thickness: t) W
tb

Lpc Ltb L
Lp

(b) Double pin type

Fig. 5.4.2: Definitions of dimensions of tab plates and pin chucks

t pc
t ｔｂ
t
Wpc

Wtb

Lpc Ltb L
Lp

(a) Example 1
t pc
ttb
ttb
t
Wpc

Wtb

Lpc Ltb L
Lp

(b) Example 2

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tpc
ttb
t
Welds
Wpc

Wtb

W
Lpc Ltb L

Lp

(c) Example 3

tpc
ttb
t
Wpc

Wtb

Lpc Ltb L
Lp

(d) Example 4
ttb
t
Wtb

Ltb L

Lp

(e) Example 5

Fig. 5.4.2.1: Examples of the shapes of tab plates and pin chucks

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5.4.2.2 Tab plates tab plates attached to both ends of a test
specimen are different, the shorter length is to be
.1 The tolerances of tab plate dimensions are used as the tab length, Ltb.
shown in Table 5.4.2.2. When the lengths of the

Table 5.4.2.2: Tolerances of tab plate dimensions

Tab plate thickness, ttb 0.8t ≤ ttb ≤ 1.5t

Tab plate width, Wtb W ≤ Wtb ≤ 2.0W
Total length of a test specimen and tab plates, L + 2Ltb L + 2Ltb ≥ 3.0W
(Total length of a test specimen and a single tab plate L + Ltb) (L + Ltb ≥ 2.0W)
Tab plate length (Lt)/Tab plate width, (W) Ltb/W ≥ 1.0

5.4.2.3 Pin chucks 5.4.3 Welding of test specimen and tab plates

The pin chuck width, Wpc, is to be in principle 5.4.3.1 Test specimen, tab plates, and pin chucks
equal to or more than the tab plate width, Wtb. are to be connected by welding. The welds are to
have a sufficient force bearing strength.
The pin chucks are to be designed to have a
sufficient load bearing strength. When pin chucks 5.4.3.2 As shown in Fig. 5.4.3.2 (a), the flatness
attached to both ends of an integrated specimen (angular distortion, linear misalignment) of the
are asymmetric, the length of the shorter one weld between a test specimen and a tab plate is
shall be used as the pin chuck length, Lpc. to be 4 [mm] or less per 1 [m]. In the case of
preloading, however, it is acceptable if the value
The distance between the pins, Lp, is obtained after preloading satisfies this condition. As shown
from the equation below. In the case as shown in in Fig. 5.4.3.2 (b), the accuracy of the in-plane
Fig.5.4.2.1 (e), Example 5, Lp is obtained by loading axis is to be 0.5% or less of the distance
setting Lpc = 0. between the pins, and the accuracy of the out-of-
plane loading axis is to be 0.4% or less of the
Lp  L  2 Ltb  2Lpc distance between the pins.

≤4mm

1m

(a) Flatness of weld between test specimen and tab plate

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≤0.004Lp

≤0.005Lp

Lp

(b) Accuracy of in-plane and out-of-plane loading axes

Fig. 5.4.3.2: Dimensional accuracy of weld between test specimen and tab plate

5.5 Test Methods ±100 mm in the test specimen length

direction, the deviation from the
The following methods are to be followed for temperature at the centre position in the
conducting the arrest toughness test. length direction is to be controlled within
±5 degree C. However, when
5.5.1 Temperature control methods temperature measurement is not
performed at the centre position in the
5.5.1.1 A predetermined temperature gradient is length direction, the average
to be established across a test specimen width by temperature at the closest position is to
soldering at least nine thermocouples to the test be used as the temperature at the centre
specimen for temperature measurement and position in the length direction.
control.
(c) At the same position in the width
5.5.1.2 Temperature gradient is to be established direction, the deviation of the
in accordance with the following conditions: temperature on the front and back
surfaces is to be controlled within ±5
(a) A temperature gradient of 0.25 - 0.35 degree C.
degree C/mm is to be established in a
test specimen width range of 0.3W - 5.5.2 Crack initiation methods
0.7W. When measuring the
temperatures at the centre position of the 5.5.2.1 Impact energy is to be applied to a test
test specimen thickness, it is to be kept specimen to initiate a crack. However, if the
within ±2 degree C for 10 minutes or energy is excessive, it may influence the test
more, whereas when measuring the results. In that case, the results would be treated
temperatures on the front and back as invalid data in accordance with the judgment
surface positions of the test specimen, it criteria specified in 5.7.2. It is recommended to
is to be kept within ±2 degree C for (10＋ use the following equation and Figure 5.5.2.1 as
0.1t [mm]) minutes or more taking guides for obtaining valid data.
account of the time needed for soaking
to the centre. If the temperature gradient Ei
at 0,3W - 0,7W is less than 0.25 degree  min (1.2  40 , 200 )
C/mm, crack arrest may become difficult, t
and if the gradient is larger than 0.35
degree C/mm, the obtained arrest Where the variables have the following units: Ei
toughness may be too conservative. [J], t [mm], and σ [N/mm2], and min means the
minimum of the two values.
(b) At the test specimen width centre
position (i.e., 0.5W), and in the range of

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400 (a) Loading rate
350 There is no specification of loading rate,
300 but it is to be determined considering that
an excessively slow loading rate may
250
prolong the temperature control period,
Ei /t [J/mm]

200 thereby allowing the temperature

150 distribution to depart from the desired
100
condition and an excessively fast loading
Recommendation rate may cause over-shooting of the
50
load.
0
0 50 100 150 200 250 300
σ [N/mm 2 ]
(b) Applied stress/yield stress ratio
Applied stress is to be within the range
shown by equation below.
Fig.5.5.2.1 Recommended range of impact
energy 2
𝜎 𝜎
5.6 Test Procedures
3
As a guidance, a value equal to 1/6 of σY0
The following are the procedures for testing brittle or more is desirable. If applied stress is
crack arrest toughness. larger than that specified by the equation
above, the test may give a non-
5.6.1 Pre-test procedures conservative result.
.1 Install an integrated specimen in the testing .7 To initiate a crack, the notch may be cooled
machine. further immediately before impact on the
condition that the cooling does not disturb the
.2 Mount a cooling device on the test specimen. temperature in the range of 0.3W - 0.7W. The test
A heating device may also be mounted on the temperature in this case is to be the measured
test specimen. temperature obtained from the temperature
record immediately before the further notch
.3 Install an impact apparatus specified in 5.3.2, cooling.
on the testing machine. Place an appropriate
reaction force receiver as necessary. .8 Record the force value measured by a force
recorder.
Note: The above procedures 5.6.1.1 through
5.6.1.3 do not necessarily specify the order of 5.6.2 Loading procedures
implementation, and they may be completed, for
example, on the day before the test. .1 After holding a predetermined force for 30
seconds or more, apply an impact to the wedge
.4 After checking that all measured values of the using the impact apparatus. If a crack initiates
thermocouples indicate room temperature, start autonomously and the exact force value at the
cooling. The temperature distribution and the time of the crack initiation cannot be obtained, the
holding time is to be as provided in the test is invalid.
specifications in 5.5.1.
.2 After the impact, record the force value
.5 Set an impact apparatus, as specified in 5.3.2 measured by the force recorder.
so that it can supply predetermined energy to the
test specimen. .3 When the force after the impact is smaller than
the test force, consider that crack initiation has
.6 Apply force to the test specimen until it reaches occurred.
the predetermined value. This force is applied
after temperature control to prevent autonomous Note: An increase in the number of times of
crack initiation during force increase. impact may cause a change in the shape of the
Alternatively, temperature control may be notch of the test specimen. Since the number of
implemented after loading. The loading rate and impact has no effect on the value of brittle crack
applied stress are to satisfy the conditions (a) and arrest toughness, no limit is specified for the
(b) described below, respectively. number of impact. However, because the
temperature gradient is often distorted by impact,
the test is to be conducted again, beginning from

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temperature control when applying repeated

impact to the wedge. (a) Crack re-initiation
In the case where a brittle crack has re-initiated
.4 When crack initiation, propagation, and arrest from an arrested crack, the original arrest position
are observed, remove the force. is defined as the arrest crack position. Here re-
initiation is defined as the case where a crack and
5.6.3 Procedures after testing re-initiated cracks are completely separated by a
stretched zone and brittle crack initiation from the
.1 Remove the impact apparatus. stretched zone can be clearly observed. In the
case where a crack continuously propagates
.2 Remove the cooling device, thermocouples, partially in the thickness direction, the position of
and strain gauges. the longest brittle crack is defined as the arrest
position.
.3 Return the temperature of the test specimen to
room temperature. For that purpose, the test (b) Crack branching
specimen may be heat-tinted using a gas burner In the case where a crack deviates from the
or the like. If it is necessary to prevent heating of direction vertical to the loading direction, the
the fracture surface, this method is to be avoided. length projected to the plane vertical to the
loading line is defined as the arrest crack length.
.4 After gas-cutting an uncracked ligament, use Similarly, in the case of crack branching, the
the testing machine to cause ductile fracture, as length of the longest branch crack projected to
necessary. Alternatively, it is also possible to gas- the plane vertical to the loading line is defined as
cut the uncracked ligament after using the testing the branch crack length. More specifically, from
machine to develop a ductile crack to a sufficient the coordinates (xa, ya) of the arrest crack tip
length. position and the coordinates (xbr, ybr) of the
branch crack tip position shown in Fig. 5.6.4.2,
5.6.4 Observation of fracture surfaces obtain the angle θ from the x-axis and define xa
as the arrest crack length, a. Here, x is the
.1 Photograph the fracture surfaces and coordinate in the test specimen width direction,
propagation path. and the side face of the impact side is set as x =
0; y is the coordinate in the test specimen length
.2 Measure the longest length of the arrest crack direction, and the notch position is set as y = 0.
tip in the plate thickness direction, and record
the result as the arrest crack length. The arrest .3 Prepare a temperature distribution curve (line
crack length is to include the notch length. In the diagram showing the relation between the
case where a crack deviates from the direction temperature and the distance from the test
vertical to the loading direction, the length specimen top side) from the thermocouple
projected to the plane vertical to the loading line measurement results, and obtain the arrest
is defined as the arrest crack length. In the temperature T corresponding to the arrest crack
following cases, however, the results are to be length.
judged according to the methods described for
each case.

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(a) Branching from notch (b) Branching during brittle crack propagation

Fig. 5.6.4.2: Measurement methods of main crack and branch crack length

5.7 Determination of arrest toughness 5.7.1.1, the length of the arrested crack
determined by 5.6.4 is valid. If any of the
5.7.1 Judgement of arrested crack conditions is not met, the arrest toughness
calculated from 5.7.3 is invalid.
5.7.1.1 When an arrested crack satisfies all of the
conditions (a) through (d) below as shown in Fig.

Fig. 5.7.1.1: Necessary conditions for arrest crack position

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(a) Conditions for crack propagation path straight crack of the same a. The calculation
method of Ks for the main crack and a straight
All of the crack path from crack initiation to arrest crack is obtained from equation (1) below.
is to be within the range shown in Fig. 5.7.1.1(a).
However, in the case where a main crack tip lies      
within this range but a part of the main crack K  KI cos3    3KII cos2   sin 
passes outside the range, the arrest toughness  2  2  2 (1)
may be assessed as valid if the temperature at
the most deviated position of the main crack in
the y direction is lower than that at y = 0, and also
K for the main crack falls within ± 5% of K for a

Fig. 5.7.1.1 (a): Allowable range of main crack propagation path

(b) Conditions for crack arrest length In the case where 50 mm <|𝑦 |≤ 100 mm and 𝜃≤
30°, the result is valid only when the temperature
0.3 0.7 (2) at x = 0.5W and y = ±100 mm falls within ± 2.5C
of that at x = 0.5W and y = 0.

1.5 (3) (d) Conditions for crack branching:

0.15 (4)
0.6 (6)

Note: Equation (4) ensures minimal influence of 5.7.2 Assessment of impact energy
force drop at the centre of the specimen which
might be caused by crack propagation and 5.7.2.1 Impact energy is to satisfy equation (7). If
reflection of the stress wave at the two ends of it does not satisfy the equation, the value of arrest
the specimen. However, application of equation toughness calculated from the equations in 5.7.3
(4) is not necessarily required if the strain and the is invalid.
crack length have been dynamically measured
and the value of the strain at the time of arrest is Conditions for impact energy:
90% or more of the static strain immediately
before crack initiation.
Ei 5a  1050 1.4W
≤ ………………(7)
(c) Conditions for crack straightness: Es  Et 0.7W  150
|𝑦 | 50 𝑚𝑚 (5) 𝑎
where0.3 ≤ ≤ 0.7
𝑊

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where the variables have the following units: a If the conditions specified in 5.7.1 and 5.7.2 are
[mm], and W [mm]. not satisfied, the Kca calculated from equation
(11) is invalid.
Ei is impact energy calculated from the equation
(8). Es and Et are calculated from equations (9) 5.8 Reporting
and (10), respectively.
5.8.1 The reporting sheet for brittle crack arrest
Note1: If equation (7) is not satisfied, the test results is indicated in Table 5.8.1. The
influence of impact energy on the stress intensity following items are to be reported:
factor is too large to obtain an accurate arrest
toughness. (1) Test material: Steel type and yield stress at
room temperature
Note 2: In the case where the tab plates are
multistage as shown in Fig. 5.4.2.1 (b), calculate (2) Testing machine: Capacity of the testing
and total the strain energy of each tab plate using machine
equation (9).
(3) Test specimen dimensions: Thickness, width,
Note3: In the case where tab plate widths are length, angular distortion, and linear
tapered as shown in Fig. 5.4.2.1 (d), calculate the misalignment
strain energy based on elastostatics.
(4) Integrated specimen dimensions: Tab plate
thickness, tab plate width, integrated specimen
Ei  m g h length including the tab plates, and distance
between the loading pins
(8)
9 2
10 F L
Es  (5) Test conditions: Applied force, applied stress,
2E W t temperature gradient, impact energy, and the
(9)
ratio of impact energy to the strain energy stored
10 F  L tb
9 2 L pc 
 in the integrated specimen (sum of test specimen
Et  

E  W tb t tb W pc t pc  strain energy and tab plate strain energy)
 (10)
(6) Test results
where the variables have the following units:
(a) Judgment of arrest: Crack length,
Es [J], Et [J], F [MN], E [N/mm2], L [mm], W
presence or absence of crack branching,
[mm], and t [mm]. main crack angle, presence or absence
of crack re-initiation, and arrest
5.7.3 Calculation of arrest toughness temperature

5.7.3.1 The arrest toughness, Kca, at the (b) Arrest toughness value
temperature, T, is to be calculated from equation
(11) using the arrest crack length, a, and the (7) Temperature distribution at moment of
applied stress, σ, judged by 5.7.1. Calculate σ impact: Thermocouple position, temperature
from equation (12). value, and temperature distribution

1/ 2 (8) Test specimen photographs: Crack

 2W   a   propagation path (one side), and brittle crack
Kca    a  tan   fracture surface (both sides)
  a  2W  
(11)
(9) Dynamic measurement results: History of
10 6 F
 crack propagation velocity, and strain change at
Wt pin chucks
(12)

where the variables have the following units: Note: Item (9) is to be reported as necessary.
F [MN], W [mm], and t [mm].

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Table 5.8.1: Report sheet for brittle crack arrest test results

Conditions/ Valid/
Item Details Symbol Unit
Results Invalid
Steel type － － －
(1) Test material
Yield stress at room temperature σY0 N/mm2 －
(2) Test equipment Testing machine capacity － MN －
Thickness t mm
(3) Test specimen Width W mm
dimensions Length L mm
Angular distortion ＋ linear misalignment － mm/m
Tab plate thickness ttb mm
(4) Integrated
Tab plate width Wtb mm
specimen
Test specimen length including a tab plate L + Ltb mm
dimensions
Distance between loading pins Lp mm
Applied force F MN
Applied stress σ N/mm2
Temperature gradient － C /mm
(5) Test conditions
Impact energy Ei J
Ratio of impact energy to strain energy
Ei/(Es+Et) －
stored in integrated specimen
Crack length a mm
Presence/ absence of
－ － －
crack branching
Judgment of Ratio of branch crack
xbr/xa －
crack length to main crack
(6) Test results propagation/ Main crack angle θ degree (°)
arrest Presence/ absence of
－ －
crack re-initiation
Temperature at crack
T C
arrest position
Arrest toughness value Kca N/mm3/2
Temperature measurement position － Attached － －
(7) Temperature
Temperature at each temperature
distribution at － Attached C －
measurement position
moment of impact
Temperature distribution curve － Attached －
(8) Test specimen Crack propagation path － Attached －
photographs Brittle crack fracture surface (both sides) － Attached －
(9) Dynamic History of crack propagation velocity － Attached －
measurement
results Strain change at pin chucks － Attached －

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Appendix A

Method for obtaining Kca at a specific temperature and the evaluation

A1 General tests to add at least two data and apply the

procedure in A2.2.2 to the data.
This Appendix specifies the method for
conducting multiple tests indicated in Section 5, .4 The value of K0 exp(c/TD) is defined as the
to obtain Kca value at a specific temperature TD. estimated value of Kca at TD. The estimated value
for the temperature corresponding to a specific
A2 Method value of Kca can be obtained from TK =
c/log(Kca/K0).
A2.1 A number of experimental data show
dependency of Kca on arrest temperature, as If the condition specified in A2.2.3 is not met,
expressed by equation (A.1), where TK [K] (= T these estimated values are to be treated as
[C]＋273), c and K0 are constants. reference values.

A3 Evaluation
 c 
K ca  K 0 exp 
 TK  (A.1)
A3.1 The straight-line approximation of arrhenius
plot for valid Kca data by interpolation method are
to comply with either of the following (a) or (b):
A2.2 The arrest toughness at a required
temperature TD [K] can be obtained by following
(a) The evaluation temperature of Kca (i.e. -
the procedures below.
10 degree C) is located between the
upper and lower limits of the arrest
.1 Obtain at least four valid Kca data.
temperature, with the Kca corresponding
to the evaluation temperature not lower
.2 Approximating log Kca by a linear expression of
than the required Kca (e.g. 6,000 N/mm3/2
1/TK, determine the coefficients log K0 and c for
or 8,000 N/mm3/2), as shown in Fig. A.1.
the data described in A2.2.1 by using the least
square method.
(b) The temperature corresponding to the
1 required Kca (e.g. 6,000 N/mm3/2 or 8,000
log K ca  log K 0  c N/mm3/2) is located between the upper
TK and lower limits of the arrest
(A.2)
temperature, with the temperature
.3 Obtain the value of (Kca/K0)exp(c/TK) for each corresponding to the required Kca not
data item. When the number of data outside the higher than the evaluation temperature
range of 0.85 through 1.15 does not exceed, the (i.e. -10 degree C), as shown in Fig. A.2.
least square method used in A2.2.2 is considered
valid. Here is an integer obtained by rounding Note: If both of (a) and (b) above are not
down the value of (number of all data divided by satisfied, additional tests are to be conducted to
6). If this condition is not met, conduct additional satisfy the conditions.

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Fig. A.1 Example for evaluation of Kca at - 10 degree C

Fig. A.2 Example for evaluation of temperature corresponding to the required Kca

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Appendix B

Double Tension Type Arrest Test

B1 Features of the test method results obtained by the brittle crack arrest
toughness test specified in Section 5.
B1.1 A double tension type arrest test specimen
consists of a main plate and a secondary loading B1.3 The specifications described in Section 5
tab. The main plate is a test plate for evaluating are to be applied to conditions not mentioned in
brittle crack arrest toughness. The secondary this Appendix B.
loading tab is a crack starter plate for assisting a
brittle crack to run into the main plate. After B2 Test specimen shapes
applying a predetermined tension force and a
temperature gradient to the main plate, a B2.1 The recommended shapes of the entire
secondary force is applied to the secondary double tension type arrest test specimen and the
loading tab by a secondary loading device to secondary loading tab are shown in Figures B.1
cause a brittle crack to initiate and run into the and B.2, respectively. Section 5.4.2 is to be
main plate. The arrest toughness is evaluated applied to the shapes of the tab plates and pin
from the arrest temperature and the crack length chucks.
in the main plate.
Note: Because of the narrowness of the
B1.2 The narrow connection part of the main connection part, slight crack deviation may lead
plate and the secondary loading tab in this test to failure of the crack to enter the main plate. The
suppress the flow of the tension stresses of the optimum shape design of the secondary loading
secondary loading tab into the main plate. The tab depends on the type of steel and testing
values of arrest toughness obtained by this conditions.
method can be considered the same as the

Secondary
460
loading tab 320

Machined for
easy brittle crack
initiation
500

200
Main plate
75
5

80
500 Shaped for stress deconcentration
[mm] (e. g., large curvature radius) [mm]

Fig. B.1 Example of shape of Fig. B.2 Example of shape of

entire test specimen secondary loading tab

B3 Temperature conditions and temperature using a cooling box and a coolant. The
control methods temperature of the secondary loading tab can be
measured using thermocouples as described in
B3.1 The specifications for temperature gradients Section 5.
and methods for establishing the temperature
gradient are described in 5.1 of this Section. B4 Secondary loading method

B3.2 In addition, in the double tension type arrest A secondary loading device is used to apply force
test, the secondary loading tab must be cooled. to the secondary loading tab. The secondary
The secondary loading tab is to be cooled without loading device is to satisfy the conditions below.
affecting the temperature gradient of the main
plate. As in the cooling method for test specimens B.4.1 Holding methods of secondary loading
described in Section 5, cooling may be applied device

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loading tab. However, other methods may be

B4.1.1 To avoid applying unnecessary force to used. Section 5.4.2 is to be applied to the shapes
the integrated specimen, the secondary loading of the tab plates and pin chucks.
device is to be held in an appropriate way.
Suspension type or floor type holding methods B4.3 Loading method
can be used.
In the suspension type method, the secondary B4.3.1 The method of loading the secondary
loading device is suspended and held by using a loading tab is to be a pin type loading method. A
crane or a similar device. In the floor type loading method other than a pin type may be
method, the secondary loading device is lifted used by agreement among the parties
and held by using a frame or a similar device. concerned. The loading rate is not specifically
specified because it does not have a direct
B.4.2 Loading system influence on the crack arrest behavior of the main
plate.
B4.2.2 A hydraulic type loading system is most
suitable for applying a force to the secondary

Section 6

Isothermal Crack Arrest Temperature (CAT) Test

6.1 Scope Section, the other test parameters are to be in

accordance with Section 5.
6.1.1 This Section is applicable to steels with
thickness over 50 [mm] and not greater than 100 6.1.4 Chapter 3, Section 10, Table 10.1.3
[mm] for evaluating brittle crack arrest properties specifies the relevant requirements for the brittle
by the Crack Arrest Temperature (CAT) method. crack arrest property described by the crack
arrest temperature (CAT).
6.1.2 Requirements for test procedures and test
conditions when using the isothermal crack arrest 6.1.5 The manufacturer is to submit the test
test to determine a valid test result under procedure to IRS for review prior to testing.
isothermal conditions and in order to establish the
crack arrest temperature (CAT) are specified in 6.2 Symbols
this Section.
Table 6.2 supplements symbols in Table 5.2,
6.1.3 This method uses an isothermal Section 5 with specific symbols for the isothermal
temperature in the test specimen being test
evaluated. Unless otherwise specified in this

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Table 6.2: Symbols used and their meanings

(These are supplementary to Table 5.2/ Section 5)

Symbol Unit Significance

t mm Test specimen thickness
L mm Test specimen length
W mm Test specimen width
aMN mm Machined notch length on specimen edge
LSG mm Side groove length on side surface from the specimen edge. LSG is
defined as a groove length with constant depth except a curved
section in depth at side groove end.
dSG mm Side groove depth in section with constant depth
LEB - min mm Minimum length between specimen edge and electron beam re-
melting zone front
LEB-s1, -s2 mm Length between specimen edge and electron beam re-melting zone
front appeared on both specimen side surfaces
LLTG mm Local temperature gradient zone length for brittle crack runway
aarrest mm Arrested crack length
Ttarget °C Target test temperature
Ttest °C Defined test temperature
Tarrest °C Target test temperature at which valid brittle crack arrest behaviour is
observed
σ N/mm2 Applied test stress at cross section of W x t
SMYS N/mm2 Specified minimum yield strength of the tested steel grade to be
approved
CAT °C Crack arrest temperature, the lowest temperature, Tarrest, at which
running brittle crack is arrested

6.3 Testing equipment 6.4 Test specimens

6.3.1 The test equipment to be used is to be of 6.4.1 Impact type crack initiation
the hydraulic type of sufficient capacity to provide
a tensile load equivalent to ⅔ of SMYS of the 6.4.1.1 Test specimens are to be in accordance
steel grade to be approved. with Section 5, Cl. 5.4 unless otherwise specified
in this Section.
6.3.2 The temperature control system is to be
equipped to maintain the temperature in the 6.4.1.2 Specimen dimensions are indicated in
specified region of the specimen within ±2oC from Fig. 6.4.1.2. The test specimen width is to be 500
Ttarget. [mm]. The test specimen length, L is to be equal
or greater than 500 [mm].
6.3.3 Methods for initiating the brittle crack may
be of drop weight type, air gun type or double 6.4.1.3 V-shape notch for brittle crack initiation is
tension tab plate type. machined on the specimen edge of the impact
side. The whole machined notch length is to be
6.3.4 The detailed requirements for testing equal to 29 [mm] with a tolerance range of ±1
equipment are specified in Section 5, Cl. 5.3. [mm].

6.4.1.4 The requirements for side grooves are

specified in 6.4.4.

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Fig. 6.4.1.2: Test specimen dimensions for an impact type specimen

Note: Saw cut notch radius may be machined in the range 0.1mmR and 1mmR in order to control a brittle
crack initiation at test.

6.4.2 Double tension type crack initiation 6.4.3.4 The EBW embrittlement is recommended
to be prepared before specimen contour
6.4.2.1 Section 5, Appendix B may be referred machining.
for the shape and sizes in secondary loading tab
and secondary loading method for brittle crack 6.4.3.5 In EBW embrittlement, zone is to be of an
initiation. appropriate quality.

6.4.2.2 In a double tension type test, the Note: EBW occasionally behaves in an unstable
secondary loading tab plate may be subject to manner at start and end points. EBW line is
further cooling to enhance an easy brittle crack recommended to start from the embrittled zone
initiation. tip side to the specimen edge with an increasing
power control or go/ return manner at start point
6.4.3 Embrittled zone setting to keep the stable EBW.

6.4.3.1 An embrittled zone is to be applied to 6.4.3.6 In LTG system, the specified local
ensure the initiation of a running brittle crack. temperature gradient between machined notch
Either Electron Beam Welding (EBW) or Local tip and isothermal test region is regulated after
Temperature Gradient (LTG) may be adopted to isothermal temperature control. LTG temperature
facilitate the embrittled zone. control is to be achieved just before brittle crack
initiation, nevertheless the steady temperature
6.4.3.2 In EBW embrittlement, electron beam gradient through the thickness shall be ensured.
welding is applied along the expected initial crack
propagation path, which is the centre line of the 6.4.4 Side grooves
specimen in front of the machined V- notch.
6.4.4.1 Side grooves on side surface can be
6.4.3.3 The complete penetration through the machined along the embrittled zone to keep
specimen thickness is required along the brittle crack propagation straight. Side grooves
embrittled zone. One side EBW penetration is are to be machined in the specified cases as
preferable, but dual sides EB penetration may specified in this sub-section.
also be adopted when the EBW power is not
enough to achieve the complete penetration by 6.4.4.2 In EBW embrittlement, side grooves are
one side EBW. not necessarily mandatory. Use of EBW avoids
the shear lips. However, when shear lips are

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evident on the fractured specimen, e.g. shear lips 6.4.4.5 When side grooves would be introduced,
over 1 [mm] in thickness in either side then side the side groove depth, the tip radius and the open
grooves are to be machined to suppress the angle are not regulated, but are adequately
shear lips. selected in order to avoid any shear lips over
1mm thickness in either side. An example of side
6.4.4.3 In LTG embrittlement, side grooves are groove dimensions is shown in Fig. 6.4.4.5.
mandatory. Side grooves with the same shape
and size are to be machined on both side 6.4.4.6 Side groove end is to be machined to
surfaces. make a groove depth gradually shallow with a
curvature larger than or equal to groove depth,
6.4.4.4 The length of side groove, LSG is to be no dSG. Side groove length, LSG is defined as a
shorter than the sum of the required embrittled groove length with constant depth except a
zone length of 150 [mm]. curved section in depth at side groove end.

Figure 6.4.4.5: Side groove configuration and dimensions

6.4.5 Nominal length of embrittled zone 6.4.5.2 EBW zone length is regulated by three
measurements on the fracture surface after test
6.4.5.1 The length of embrittled zone is to be as shown in Figure 6.4.5.2, LEB-min between
nominally equal to 150 [mm] in both systems of specimen edge and EBW front line, and LEB-s1
EBW and LTG. and LEB-s2.

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Fig. 6.4.5.2: Definition of EBW length

6.4.5.3 The minimum length between specimen 6.5 Test Method

edge and EBW front line, LEB-min should be no
smaller than 150 [mm]. However, it can be 6.5.1 Preloading
acceptable even if LEB-min is no smaller than
150mm-0.2t, where t is specimen thickness. 6.5.1.1 Preloading at room temperature can be
When LEB-min is smaller than 150 [mm], a applied to avoid unexpected brittle crack initiation
temperature safety margin is to be considered at test. The applied load value is to be no greater
into Ttest (See Cl. 6.8.1.2). than the test stress. Preloading can be applied at
higher temperature than ambient temperature
6.4.5.4 Another two are the lengths between when brittle crack initiation is expected at
specimen edge and EBW front appeared on both preloading process. However, the specimen is
side surfaces, as denoted with LEB-s1 and LEB-s2. not to be subjected to temperature higher than
Both of LEB-s1 and LEB-s2 are to be no smaller than 100 [oC].
150 [mm].
6.5.2 Temperature measurement and control
6.4.5.5 In LTG system, LLTG is set as 150 [mm].
6.5.2.1 Temperature control plan showing the
6.4.6 Tab plate / pin chuck details and welding number and position of thermocouples is to be in
of test specimen to tab plates accordance with this sub-section.

6.4.6.1 The configuration and size of tab plates 6.5.2.2 Thermocouples are to be attached to both
and pin chucks may be referred in Section5, sides of the test specimen at a maximum interval
Cl.5.4.2. The welding distortion in the integrated of 50 [mm] in the whole width and in the
specimen, which is welded with specimen, tab longitudinal direction at the test specimen centre
plates and pin chucks, is to be also within the position (0.5 W) within the range of ±100 [mm]
requirements stipulated in Section 5, Cl. 5.4.3. from the centreline in the longitudinal direction,
refer to Fig. 6.5.2.2.

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Fig. 6.5.2.2: Locations of temperature measurement

6.5.2.3 For EBW embrittlement .3 The machined notch tip can be locally cooled
to easily initiate brittle crack. Nevertheless, the
.1 The temperatures of the thermocouples across local cooling is not to disturb the steady
the range of 0.3W~0.7W in both width and temperature control across the range of
longitudinal directions are to be controlled within 0.3W~0.7W.
± 2°C of the target test temperature, Ttarget.
6.5.2.4 For LTG embrittlement
.2 When all measured temperatures across the
range of 0.3W~0.7W have reached Ttarget, steady .1 In LTG system, in addition to the temperature
temperature control is to be kept at least for 10 + measurements shown in Fig. 6.5.2.2, the
0.1 x t [mm] minutes to ensure a uniform additional temperature measurement at the
temperature distribution into mid-thickness prior machine notch tip, A0 and B0 is required.
to applying test load. Thermocouples positions within LTG zone are
indicated in Fig. 6.5.2.4.1.

Figure 6.5.2.4.1: Detail of LTG zone and additional thermocouple A0

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.2 The temperatures of the thermocouples across Zone III. The acceptable range for each
the range of 0.3W~0.7W in both width and temperature gradient is listed in Table 6.5.2.4.5.
longitudinal directions are to be controlled within
± 2oC of the target test temperature, Ttarget. .6 Two temperature measurements at A2, B2 and
However, the temperature measurement at 0.3W A3, B3 are to satisfy the following requirements:
(location of A3 and B3) is to be in accordance with
6.5.2.4.6 below. T at A3, T at B3 < Ttarget – 2oC
T at A2 < T at A3 – 5oC
.3 Once the all measured temperatures across T at B2 < T at B3 – 5oC
the range of 0.3W~0.7W have reached Ttarget,
steady temperature control is to be kept at least .7 There are no requirements for T at A0 and T at
for 10 + 0.1 x t [mm] minutes to ensure a uniform A1 temperatures when T at A3 and T at A2 satisfy
temperature distribution into mid-thickness, then the requirements above. Similar requirements
the test load is to be applied. are applicable for Face B.

.4 LTG is controlled by local cooling around the .8 The temperatures from A0, B0 to A3, B3 are to
machined notch tip. LTG profile is to be recorded be decided at test planning stage. Table 6.5.2.4.5
by the temperature measurements from A0 to A3 may be referred for the recommended
shown in Fig. 6.5.2.4.4 below. temperature gradients in three zones, Zone I,
Zone II and Zone III in LTG zone.
.5 LTG zone is established by temperature
gradients in three zones, Zone I, Zone II and

Fig. 6.5.2.4.4: Schematic temperature gradient profile in LTG zone

Table 6.5.2.4.5: Acceptable LTG range

Zone Location from edge Acceptable range of temperature gradient

Zone I 29mm – 50mm 2.00 °C/mm – 2.30 °C/mm
Zone II 50mm – 100mm 0.25 °C/mm – 0.60 °C/mm
Zone III1) 100mm – 150mm 0.10 °C/mm – 0.20 °C/mm

Note: The zone III arrangement is mandatory

.9 The temperature profile in LTG zone

mentioned above is to be ensured after holding .10 The acceptance of LTG in the test is to be
time at least for 10 + 0.1 x t [mm] minutes to decided from Table 6.5.2.4.5 based on the
ensure a uniform temperature distribution into measured temperatures from A0 to A3.
mid-thickness before brittle crack initiation.

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6.5.2.5 For double tension type crack initiation 6.6 Measurements after test and test
specimen: validation judgement

.1 Temperature control and holding time at 6.6.1 Brittle crack initiation and validation
steady state is to be the same as the case of
EBW embrittlement specified in 6.5.2.3 or the 6.6.1.1 If brittle crack spontaneously initiates
case of LTG embrittlement specified in Section before the test force is achieved or the specified
6.5.2.4. hold time at the test force is not achieved, the test
would be considered as invalid.
6.5.3 Loading and brittle crack initiation
6.6.1.2 If brittle crack spontaneously initiates
6.5.3.1 Prior to testing, a target test temperature without impact or secondary tab tension but after
(Ttarget) is to be selected. the specified time at the test force is achieved,
the test would be considered as a valid initiation.
6.5.3.2 Test procedures are to be in accordance The following validation judgments of crack path
with Section 5, Cl. 5.6 except that the applied and fracture appearance are to be examined.
stress is to be ⅔ of SMYS of the steel grade
tested. 6.6.2 Crack path examination and validation

6.5.3.3 The test load is to be held at the test target 6.6.2.1 When brittle crack path in embrittled zone
load or higher for a minimum of 30 seconds prior deviates from EBW line or side groove in LTG
to crack initiation. system due to crack deflection and/ or crack
branching, the test would be considered as
6.5.3.4 Brittle crack can be initiated by impact or invalid.
secondary tab plate tension after all of the
temperature measurements and the applied 6.6.2.2 All of the crack path from embrittled zone
force are recorded. end is to be within the range shown in Fig.
6.6.2.2. If not, the test would be considered as
invalid.

Fig, 6.6.2.2: Allowable range of main crack propagation path

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6.6.3 Fracture surface examination, crack length

measurement and their validation 6.6.3.5 In EBW embrittlement setting, the
penetration of brittle crack beyond the EBW front
6.6.3.1 Fracture surface is to be observed and line is to be visually examined. When any brittle
examined. The crack “initiation” and fracture appearance area continued from the EB
“propagation” are to be checked for validity and front line is not detected, the test would be invalid.
judgements recorded. The crack “arrest”
positions are to be measured and recorded. 6.6.3.6 The weld defects in EBW embrittled zone
are to be visually examined. If detected, they are
6.6.3.2 When crack initiation trigger point is to be quantified. A projecting length of defect on
clearly detected at side groove root, other than the thickness line through EB weld region along
the V-notch tip, the test would be invalid. brittle crack path is to be measured, and the total
occupation ratio of the projected defect part to the
6.6.3.3 In EBW embrittlement setting, EBW zone total thickness is defined as defect line fraction
length is quantified by three measurements of (See Fig. 6.6.3.6). When the defects line fraction
LEB-s1, LEB-s2 and LEB-min, which are defined in is larger than 10 %, the test would be invalid.
6.4.5. When either or both of LEB-s1 and LEB-s2
are smaller than 150 [mm], the test would be 6.6.3.7 In EBW embrittlement by dual sides’
invalid. When LEB-min is smaller than 150mm- penetration, if a gap on embrittled zone fracture
0.2t, the test would be invalid. surface which is induced by miss meeting of dual
fusion lines, is visibly detected at an overlapped
6.6.3.4 When the shear lip with thickness over 1 line of dual side penetration, the test would be
[mm] in either side near side surfaces of invalid.
embrittled zone are visibly observed independent
of the specimens with or without side grooves,
the test would be invalid.

Fig. 6.6.3.6: Counting procedure of defect line fraction

6.7 Judgement of ‘arrest’ or ‘propagate’ 6.7.3 When the specimen is not broken into two
pieces during testing, the arrested crack length,
6.7.1 The judgment of “arrest”, “propagate” or aarrest is to be measured on the fractured surfaces.
“invalid” would be decided based on the The length from the specimen edge of impact
requirements indicated in 6.7.2 through 6.7.6. side to the arrested crack tip (the longest
position) is defined as aarrest.
6.7.2 If initiated brittle crack is arrested and the
tested specimen is not broken into two pieces, 6.7.4 For LTG and EBW, aarrest is to be greater
the fracture surfaces should be exposed with the than LLTG and LEB-s1, LEB-s2 or LEB-min. If not, the test
procedures specified in Section 5, Cl. 5.6.3 and would be considered as invalid.
5.6.4.

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6.7.5 Even when the specimen is broken into two
pieces during testing, it can be considered as 6.8.3.2 With only the “arrest” tests, without
“arrest” when brittle crack re-initiation is clearly “propagation” test, it is decided only that CAT is
evident. Even in the fracture surface all occupied lower than Ttest in the two “arrest” tests, i.e. not
by brittle fracture, when a part of brittle crack deterministic CAT.
surface from embrittled zone is continuously
surrounded by thin ductile tear line, the test can 6.9 Reporting
be judged as re-initiation behaviour. If so, the
maximum crack length of the part surrounded 6.9.1 The following items are to be reported:
tear line can be measured as aarrest. If re-initiation
is not visibly evident, the test is judged as (i) Test material: grade and thickness
“propagate”.
(ii) Test machine capacity
6.7.6 The test would be judged as “arrest” when
the value of aarrest is no greater than 0.7W. If not, (iii) Test specimen dimensions:
the test would be judged as “propagate”. thickness t; width W and length L;
notch details and length aMN, side
6.8 Ttest, Tarrest and CAT determination groove details if machined;

6.8.1 Ttest determination (iv) Embrittled zone type: EBW or LTG

embrittlement
6.8.1.1It shall be ensured on the thermocouple
measured record that all temperature (v) Integrated specimen dimensions:
measurements across the range of 0.3W ~ 0.7W Tab plate thickness, tab plate width,
in both width and longitudinal direction are in the integrated specimen unit length
range of Ttarget ±2°C at brittle crack initiation. If including the tab plates, and distance
not, the test shall be invalid. However, the between the loading pins, angular
temperature measurement at 0.3W (location of distortion and linear misalignment
A3 and B3) in LTG system shall be exempted from
this requirement. (vi) Brittle crack trigger information:
impact type or double tension. If
6.8.1.2 If LEB-min in EBW embrittlement is no impact type, drop weight type or air
smaller than 150 [mm], Ttest can be defined to gun type, and applied impact energy.
equal with Ttarget. If not, Ttest shall be equaled with
Ttarget + 5˚C. (vii) Test conditions; Applied load;
preload stress, test stress
6.8.1.3 In LTG embrittlement, Ttest can be - Judgements for preload stress limit,
equaled with Ttarget. hold time requirement under steady
test stress.
6.8.1.4 The final arrest judgment at Ttest is
concluded by at least two tests at the same test (viii) Test temperature: complete
condition which are judged as “arrest”. temperature records with
thermocouple positions for
6.8.2 Tarrest determination measured temperatures (figure
and/or table) and target test
6.8.2.1 When at least repeated two “arrest” tests temperature.
appear at the same Ttarget, brittle crack arrest
behaviour at Ttarget will be decided (Tarrest = - Judgements for temperature
Ttarget).When a “propagate” test result is included scatter limit in isothermal region.
in the multiple test results at the same Ttarget, the
Ttarget cannot to be decided as Tarrest. - Judgement for local temperature
gradient requirements and holding
6.8.3 CAT determination time requirement after steady local
temperature gradient before brittle
6.8.3.1 When CAT is determined, one crack trigger, if LTG system is used.
“propagate” test is needed in addition to two
“arrest” tests. The target test temperature, Ttarget (ix) Crack path and fracture surface:
for “propagate” test is recommended to select tested specimen photos showing
5oC lower than Tarrest. The minimum temperature fracture surfaces on both sides and
of Tarrest is determined as CAT. crack path side view; Mark at

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“embrittled zone tip” and “arrest” Test results:

positions.
When the specimen did not break into two pieces
- Judgment for crack path after brittle crack trigger, arrested crack length
requirement. aarrest

- Judgment for cleavage trigger When the specimen broke into two pieces after
location (whether side groove edge brittle crack trigger,
or V-notch edge).
- judgement whether brittle crack re-
(x) Embrittled zone information: initiation or not.

When EBW is used: LEB-s1, LEB-s2 and LEB-min If so, arrested crack length aarrest:

- Judgement for shear lip thickness - Judgement for aarrest in the valid
requirement range (0.3W < aarrest ≤ 0.7W)

- Judgment whether brittle fracture - Final judgement either “arrest”,

appearance area continues from the “propagate” or “invalid”
EBW front line
(xi) Dynamic measurement results:
- Judgement for EBW defects History of crack propagation velocity,
requirement and strain change at pin chucks, if
needed
- Judgement for EBW lengths, LEB-s1,
LEB-s2 andLEB-min requirements 6.10 Use of test for material qualification
testing
When LTG is used: LLTG
Where required, the method can also be used for
- Judgment for shear lip thickness determining the lowest temperature at which a
requirement steel can arrest a running brittle crack (the
determined CAT) as the material property
characteristic in accordance with 6.8.3.

End of Chapter

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Chapter 3

Rolled Steel Plates, Strips, Sections and Bars

Contents
Section

1 General Requirements
2 Normal Strength Steels for Ship Structures
3 Higher Strength Steels for Ship Structures
4 High Strength Steels for Welded Structures
5 Steel for Low Temperature Service
6 Steels for Boilers and Pressure Vessels
7 Steels for Machinery Structures
8 Plates with Specified minimum through Thickness Properties (‘Z’ quality)
9 Austenitic and Duplex Stainless Steels
10 Brittle Crack Arrest Steels

Section 1

General Requirements

1.1 Scope 1.2.2 The suitability of each grade of steel for

forming and welding is to be demonstrated
1.1.1 This Chapter gives general requirements during the initial approval tests at the steel
for hot rolled plates, wide flats, strips and works. The type and the extent of testing
sections intended for use in the construction of required is at the discretion of IRS.
ships, boilers, pressure vessels and machinery
structures. These requirements are also 1.2.3 It is the manufacturer's responsibility to
applicable to hot rolled bars, except where such assure that effective process and production
materials are intended for the manufacture of controls in operation are adhered to in
bolts, shafts, etc. by machining operations only. accordance with the manufacturing
When used for this purpose hot rolled bars are specifications. Where control imperfection that
to comply with the requirements of Ch. 5. may lead to inferior quality of product occurs,
the manufacturer is to identify the cause and
1.2 Manufacture establish counter measure to prevent its
occurrence. Also the complete investigation
1.2.1 The steel is to be manufactured at the report is to be submitted to the Surveyor. Each
approved works by the open hearth, electric affected piece considered for further usage is to
furnace or one of the basic oxygen processes or be tested to the Surveyor's satisfaction.
by other processes specially approved by IRS.
The frequency of testing may be increased to
The approval of the steel works is to be carried gain confidence for subsequent products as
out in accordance with IRS Classification Notes: considered necessary.
‘Approval scheme for the manufacturing process
of normal and higher strength hull structural 1.3 Quality of materials
steels’. Also refer Chapter 1, Section 1, Cl.
1.3.2. 1.3.1 Defects not prejudicial to the proper
application of steel are not, except by special

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agreement, to be grounds for rejection. Where However, the minus tolerance is not to exceed
necessary, suitable methods of non-destructive 0.3 [mm].
examination may be used for the detection of
harmful surface and internal defects. The extent
of this examination, together with appropriate Table 1.4.4
acceptance standards, is to be agreed between
the purchaser, manufacturer and Surveyors. Minus tolerance on
Nominal thickness
nominal thickness
1.4 Thickness tolerance of plates and wide [mm]
[mm]
flats with width  600 [mm] ≥ 3 to < 5 -0.3

1.4.1 Following requirements are applicable to  5 to < 8 -0.4

the tolerance on thickness of steel plates and  8 to < 15 -0.5
wide flats with widths of 600 [mm] or greater  15 to < 25 -0.6
(herein after referred to as: product or products)
with thickness of 5 [mm] and over, covering the  25 to < 40 -0.7
following :  40 to < 80 -0.9
≥ 80 to < 150 -1.1
(i) Normal and higher strength hull
structural steels (Refer Sec 2, and Sec ≥ 150 to < 250 -1.2
3) ≥ 250 -1.3
(ii) High strength steels for welded structure
( Refer Sec 4) 1.4.6 The plus tolerance on nominal thickness is
(iii) Steel for machinery structures (Refer to be in accordance with a recognized national
Sec 7) or international standard or as specified.

These requirements do not apply to products 1.4.7 The tolerance on sections (except for wide
intended for the construction of boilers, pressure flats) are to be in accordance with the
vessels and independent tanks, e.g. for the requirements of recognized international or
transportation of liquefied gases or chemicals. national standard.

These requirements do not apply to products 1.4.8 The tolerances on nominal thickness are
intended for the construction of lifting not applicable to areas repaired by grinding. For
appliances. areas repaired by grinding, the requirements of
Sec.2, 2.7.4.1 are to be applied, unless stricter
1.4.2 The tolerance on thickness of a given requirements as per a recognized standard are
product are defined as follows: specified by the purchaser.

a) Minus tolerance is the lower limit of the 1.4.9 For materials intended for applications as
acceptable range below the nominal detailed in Sec. 5 and 6, no minus tolerance is
thickness. permitted in the thickness of plates and strip.
b) Plus tolerance is the upper limit of the
acceptable range above the nominal 1.4.10 The responsibility for verification and
thickness. maintenance of the production within the
required tolerance rests with the manufacturer.
Note : Nominal thickness is stated by the The Surveyor may require to witness some
purchaser at the time of enquiry and order. measurements.

1.4.3 The minus tolerance for products for 1.4.11 The responsibility for storage and
normal strength, higher strength and high maintenance of the delivered products with
strength quenched and tempered steels is 0.3 acceptable level of surface conditions rests with
[mm] irrespective of nominal thickness. the shipyard before the products are used in
fabrication.
1.4.4 The minus tolerance for products intended
for machinery structures are to be in accordance 1.4.12 Where zero minus tolerance is applied in
with Table 1.4.4. accordance with Class C of ISO 7452-2013 or
equivalent national or international standards,
1.4.5 The tolerance for thickness below 5 [mm] the requirements of 1.4.13 to 1.4.15 need not be
is to be in accordance with a national or applied.
international standard, e.g. Class B of ISO 7452.

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Additionally, if Class C of ISO 7452-2013 is 1.4.15.1 The requirements of 1.4.15.2 are to be
applied, it is required that the steel mill applied to the thickness measuring locations for
demonstrates to the satisfaction of IRS that the the thickness tolerance and the average
number of measurements and measurement thickness of the product.
distribution is appropriate to establish that the
mother plates produced are at or above the 1.4.15.2 At least two lines among Line 1, Line 2
specified nominal thickness. or Line 3 as shown in Fig.1.4.15.2 are to be
selected for the thickness measurements and at
1.4.13 Average thickness least three points on each selected line are to be
selected for thickness measurement. If more
1.4.13.1 The average thickness of products is than three points are taken on each line the
defined as the arithmetic mean of the number of points are to be equal on each line.
measurements made in accordance with the
requirements of 1.4.14. Note : The measurement locations apply to a
product rolled directly from one slab or steel
1.4.13.2 The average thickness of products for ingot even if the product is to be later cut by the
hull structural steels is not to be less than the manufacturer. Examples of the original
nominal thickness. measurements relative to later cut products are
shown in Fig.1.4.15.2b), It is to be noted that the
1.4.14 Thickness measurements examples shown are not representative of all
possible cutting scenarios.
1.4.14.1 The thickness is to be measured at
locations of products as defined in 1.4.15. For automated methods, the measuring points
at sides are to be located not less than 10 [mm]
1.4.14.2 Automated method or manual method but not greater than 300 [mm] from the
may be applied to the thickness measurements. transverse or longitudinal edges of the product.

1.4.14.3 The procedure and the records of For manual methods, the measuring points at
measurements are to be made available to the sides are to be located not less than 10 [mm]
Surveyor and copies provided on request. but not greater than 100 [mm] from the
transverse or longitudinal edges of the product.
1.4.15 Thickness measuring locations

Line 1
A1 A2 A3

Line 2
B1 B2 B3

C1 C2 C3
Line 3

: Measurement points
Rolling direction

Fig. 1.4.15.2a) : Locations of Thickness Measuring Points for the Original Steel Plates

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Fig. 1.4.15.2b) : Locations of Thickness Measuring Points for the Cut Steel Products

Line 1
A1 A2 A3

(i) Line 2 B1 B2 B3

C1 C2 C3
Line 3

: Measurement points

Rolling direction

Line 1
A1 A2 A3

B1 B2 B3
(ii) Line 2

C1 C2 C3
Line 3

: Measurement points

Rolling direction

Line 1

Line 2

Line 3

: Measurement points

Rolling direction

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1.5 Heat treatment, condition of supply c) Controlled rolling, CR (Normalizing Rolling,

NR) - A rolling procedure in which the final
1.5.1 All materials are to be supplied in the heat deformation is carried out in the normalising
treated conditions described in the subsequent temperature range, allowed to cool in air,
sections of this chapter unless supply in the as- resulting in a material condition generally
rolled condition is allowed. equivalent to that obtained by normalising.

1.5.2 Where the material is supplied in the as d) Quenching and Tempering, QT –

rolled condition and intended for subsequent hot Quenching involves a heat treatment
forming, the manufacturer is to carry out any process in which steel is heated to an
heat treatment which may be necessary to appropriate temperature above the Ac3,
prevent hydrogen cracking or make the material held for specific period of time and then
in a safe condition for transit and Surveyors are cooled with an appropriate coolant for the
to be advised of any such heat treatment carried purpose of hardening the microstructure.
out. This requirement is applicable mainly to Tempering subsequent to quenching is a
carbon and carbon-manganese steel products process in which the steel is reheated to an
over 50 [mm] thick and to alloy steel products. appropriate temperature not higher than the
Ac1, maintained at that temperature for a
1.5.3 Where controlled rolling or thermo- specific period of time to restore toughness
mechanical processing is permitted as an properties by improving the microstructure
alternative to normalising, these procedures and reduce the residual stress caused by
may be used subject to full details being the quenching process.
submitted and a test program being carried out
under the supervision of the Surveyors and the e) Thermo-mechanical Rolling, TM – Thermo-
test results being found satisfactory by IRS. mechanical controlled processing - this is a
These rolling processes are defined as follows: procedure which involves the strict control of
both the steel temperature and the rolling
(See Fig.1.5.3). reduction. Generally, a high proportion of
the rolling reduction is carried out close to or
a) As Rolled, AR - this procedure involves below the AR3 transition temperature and
steel being cooled as it is rolled with no may involve rolling towards the lower end of
further heat treatment. The rolling and the temperature range of the inter critical
finishing temperatures are typically in the duplex phase region thus permitting little if
austenite recrystalisation region and above any recrystallisation of the austenite. Unlike
the normalising temperature. The strength controlled rolled (normalised rolling) the
and toughness properties of steel produced properties conferred by TM (TMCP) cannot
by this process are generally less than steel be reproduced by subsequent normalising
heat treated after rolling or than steel or other heat treatment.
produced by advanced processes.
The use of accelerated cooling on
b) Normalising, N - normalising involves completion of TM-rolling may also be
heating rolled steel above the critical accepted subject to the special approval of
temperature, Ac3 and in the lower end of IRS. The same applies for use of tempering
the austenite recrystalisation region for a after completion of the TM-rolling.
specific period of time, followed by air-
cooling. The process improves the f) Accelerated cooling AcC - accelerated
mechanical properties of as rolled steel by cooling is a process, which aims to improve
refining the grain size and homogenizing the mechanical properties by controlled cooling
microstructure. with rates higher than air cooling
immediately after the final TM-rolling
operation. Direct quenching is excluded
from the accelerated cooling.

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The material properties conferred by TM rolling operation. (Refer 1.2.3). To this effect, all
and AcC cannot be reproduced by the records of actual rolling are to be reviewed
subsequent normalising or other heat by the manufacturer and occasionally by the
treatment. Surveyor.

1.5.3.1 Where NR (CR) and TM with/without When deviation from the programmed rolling
AcC are applied, the programmed rolling schedules or normalizing or quenching and
schedules are to be verified by IRS at the steel tempering procedures occurs, the manufacturer
works and are to be made available when shall take further measures required in 1.2.3 to
required by the attending Surveyor. On the the Surveyor's satisfaction.
manufacturer's responsibility, the programmed
rolling schedules are to be adhered to during the

Notes:
AR: As Rolled
N: Normalizing
CR(NR): Controlled Rolling (Normalizing Rolling)
QT: Quenching and Tempering
TM: Thermo-Mechanical Rolling (Thermo-Mechanical Controlled Process)
R: Reduction
(*): Sometimes rolling in the dual-phase temperature region of austenite and ferrite
AcC: Accelerated Cooling

Fig.1.5.3 : Schematic Diagrams of Thermo-Mechanical and Conventional Processes

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1.5.3.2 The conditions of supply and the impact one end at a position approximately one third
test requirements are detailed in subsequent from the outer edge (See Figs.1.6.1 b,c,d), or in
sections of the Chapter. the case of small sections as near as possible to
this position. In the case of channels, beams or
1.6 Test material bulb angles the test samples may alternatively
be taken from a position approximately one
1.6.1 All material in a batch presented for quarter of the width from the web centreline or
acceptance tests are to be of the same product axis (See Fig.1.6.1 c). The tensile test
form e.g. plates, flats, sections. etc., from the specimens may be prepared with their
same cast and in the same condition of supply. longitudinal axis either parallel or transverse to
the final direction of rolling.
1.6.2 Test samples
1.6.3.3 Bars and other similar products: The
a) The test samples are to be fully test specimens are to be taken so that the axis
representative of the material and, where of the test specimen is parallel to the direction of
appropriate, are not to be cut from the rolling. For small sizes, the test specimen may
material until heat treatment has been consist of a suitable length of the full cross
completed. section of the product (the impact test specimen
receiving nevertheless the necessary
b) The test specimens are not to be machining). For larger sizes, the test samples
separately heat treated in any way. are to be taken so that the axis of the test
specimen lies as near as possible to the
1.6.3 Unless otherwise agreed, the test samples following :
are to be taken from the following position :
a) for non-cylindrical sections, at one third of
1.6.3.1 Plates and flats with a width  600 the half diagonal from the outside.
[mm] : The test samples are to be taken from
one end at a position approximately midway b) for cylindrical sections, at one third of the
between the axis in the direction of the rolling radius from outside (See Fig.1.6.1 e).
and the edge of the rolled product (See Fig.1.6.1
a). Unless otherwise agreed the tensile test 1.6.3.4 For plates and flats with thicknesses in
specimens are to be prepared with their excess of 40 [mm], full thickness specimens
longitudinal axis transverse to the final direction may be prepared, but when instead a machined
of rolling. round specimen is used then the axis is to be
located at a position lying one-quarter of the
1.6.3.2 Flats with a width < 600 [mm], bulb product thickness from the surface as shown in
flats and other sections : For flats having a Fig.1.6.1.f.
width of 600 [mm] or less, bulb flats and other
sections the test specimens are to be taken from

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Fig.1.6.1 : Samples for testing

1.7 Mechanical test specimens axis of the test specimens are to be as specified
in 1.6.3.3. The notch is to be cut in a face of the
1.7.1 The tensile test specimens are to be test specimen which was originally perpen-
machined to the dimensions detailed in Ch. 2. dicular to the rolled surface. The position of the
notch is to be not nearer than 25 [mm] to a
1.7.2 Impact test specimens: The impact test flame-cut or sheared edge.
specimens are to be of the charpy V-notch type
machined to the dimensions detailed in Ch. 2 1.8 Surface inspection and dimensions
and cut with their longitudinal axis either parallel
or transverse to the final direction of rolling of 1.8.1 Surface inspection and verification of
the material. They are to be taken from a dimensions are the responsibility of the steel-
position close to one of the rolled surfaces, maker, and acceptance by the Surveyors of
except that for plates and sections over 40 [mm] material later found to be defective shall not
thick the axis of test specimens are to be one absolve the steel maker from this responsibility.
quarter of the thickness from one of the rolled The manufacturer is also responsible for
surfaces. For bars and other similar products the compliance with the general requirements

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concerning freedom from harmful internal a) The manufacturer's name or trade mark;
defects.
b) Identification mark for the grade of steel,
1.9 Freedom from defects (material supplied in the thermo-
mechanically controlled process condition is
1.9.1 All products must have a workmanlike to have the letter TM added after the
finish and must be free from defects and identification mark) ;
imperfections which may impair their proper
workability and use. This may however, include c) Cast or identification number and/or initials
some discontinuties of a harmless nature, minor which enable the full history of the item to
imperfections e.g. pittings, rolling in scale, be traced;
indentations, roll marks, scratches and grooves
which cannot be avoided completely despite d) If required by the purchaser, his order
proper manufacturing and which will not be number or other identification marks.
objected to provided they do not exceed the
acceptable limits contained herein. e) Steels, which have been specially approved
and which differ from the requirements
1.9.2 Imperfections : Notwithstanding this, the given in this Chapter are to have the letter
products may have imperfections exceeding the "S" marked after the agreed identification
discontinuities inherent to the manufacturing mark.
process, as defined under 1.9.1. In such cases,
limits for their acceptability are to be agreed with f) Steel plates that have complied with the
IRS, taking the end use of the product into requirements for corrosion resistant steel
consideration. will be identified by adding a corrosion
designation to the unified identification mark
1.9.3 Defects : Cracks, shells, sand patches for the grade of steel. The corrosion
and sharp edged seams are always considered resistant steel is to be designated according
defects which would impair the end use of the to its area of application as follows:
product and which require rejection or repair,
irrespective of their size and number. The same - Lower surface of strength deck and
applies to other imperfection exceeding the surrounding structures; RCU
acceptable limits.
- Upper surface of inner bottom plating
1.10 Special quality plate material (‘z’ quality) and surrounding structures; RCB

1.10.1 When plate material, intended for welded - For both strength deck and inner bottom
construction, will be subject to significant strains plating; RCW
in a direction perpendicular to the rolled
surfaces, it is recommended that consideration 1.11.2 Products complying with the
be given to the use of special plate material with requirements of Sec. 8 are to be marked "Z 25"
specified through thickness properties. These or ‘Z 35’ as appropriate, in addition to the
strains are usually associated with thermal material grade designation e.g. ‘EH36Z25’ or
contraction and restraint during welding, ‘EH36Z35’.
particularly for full penetration "T"- butt welds,
but may also be associated with loads applied in 1.11.3 The above particulars, but excluding the
service or during construction. Requirements for manufacturer's name or trade mark where this is
these materials are detailed in Sec. 8 and it is embossed on finished products, are to be
the responsibility of shipbuilder or fabricator to encircled with paint or otherwise marked so as
make provision for the use of this material. to be easily recognizable.

1.11 Branding of materials 1.11.4 In the event of any material bearing IRS
brand failing to comply with the test
1.11.1 Every finished item is to be clearly requirements, the brand name is to be
marked by the manufacturer in at least one unmistakably defaced.
place with IRS brand IR and the following
particulars:

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1.12 Test certificates or other documentation In the case of ‘Z’ quality steel, notation ‘Z25’ or
‘Z35’ as appropriate, is to be indicated with the
1.12.1 The Surveyor is to be supplied, in steel grade and test results are to include
duplicate, copies of the test certificates or other through thickness reduction in area (%).
documentation for all accepted materials, IRS
may require separate documents for each grade 1.12.2 Before the test certificates or shipping
of steel. These documents are to contain, in statements are signed by the Surveyor, the
addition to the description, dimensions, etc. of manufacturer is required to furnish him with a
the material at least the following particulars: written declaration stating that the material has
been made by an approved process and that it
a) Purchaser's order number and if known the has been subjected to and has withstood
ship number for which the material is satisfactorily the required tests in the presence
intended; of the Surveyor or his authorized deputy. The
following form of declaration will be accepted if
b) Identification number and/or initials; stamped or printed on each test certificate or
shipping statement with the name of steelworks
c) Identification of steel works; and initialed by the makers or an authorized
deputy:
d) Identification of the grade of steel; "We hereby certify that the material has been
made by an approved process in accordance
e) Cast number and ladle analysis; with the Rules of Indian Register of Shipping
and has been tested satisfactorily in the
f) For steel with a corrosion resistant steel presence of the surveyors of Indian Register of
designation the weight percentage of each Shipping".
element added or intentionally controlled for
improving corrosion resistance. 1.12.3 When steel is not produced at the works
at which it is rolled a certificate is to be supplied
g) Condition of supply when other than as to the Surveyor at the rolling mill stating the
rolled e.g. normalized or controlled rolled; process by which it was manufactured and the
name of the manufacturer, the number of cast
h) If the material is of rimming quality, this from which it was made and the ladle analysis.
should be stated; The Surveyors are to have access to the works
at which the steel was produced and the works
i) Test results. must be approved by IRS. Also refer Chapter 1,
Section1, Cl. 1.3.2.

Section 2

Normal Strength Steels for Ship Structures

2.1 General particular cases after consideration of the

technical circumstances involved.
2.1.1 Requirements of this section are
applicable to weldable normal strength hot-rolled 2.1.3 Requirements of this section also apply to
steel plates, wide flats, sections and bars normal strength Corrosion Resistant steels
intended for use in hull construction. Steel when such steel is used as the alternative
differing in chemical composition, deoxidation means of corrosion protection for cargo oil tanks
practice, heat treatment or mechanical as specified in the performance standard
properties may be accepted, subject to special MSC.289 (87) of Regulation 3-11, Part A-1,
agreement by IRS. Chapter II-1 of the SOLAS Convention
(Corrosion protection of cargo oil tanks of crude
2.1.2 These requirements are primarily intended oil tankers). Corrosion Resistant steels as
to apply to steel plates and wide flats not defined within this section, are steels whose
exceeding 100 [mm] in thickness and sections corrosion resistance performance in the bottom
and bars not exceeding 50 [mm] in thickness. or top of the internal cargo oil tank is tested and
For greater thickness, certain variations in the approved to satisfy the requirements in
requirements may be allowed or required in MSC.289 (87) in addition to other relevant

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requirements for hull structural steels, structural 2.5 Condition of supply
strength and construction. It is not intended that
such steels be used for corrosion resistant 2.5.1 All materials are to be supplied in a
applications in other areas of a vessel that are condition complying with Table 2.5.1 and Table
outside of those specified in the performance 2.5.2. Where alternative arrangements are
standard MSC.289 (87) of Regulation 3-11, Part permitted these are at the option of the
A-1, Chapter II-1 of the SOLAS Convention. steelmaker, unless otherwise expressly stated in
These requirements apply to plates, wide flats, the order for the material.
sections and bars in all grades up to a maximum
thickness of 50 [mm]. 2.6 Mechanical Properties

2.2 Approval 2.6.1 For tensile test either the upper yield
stress (ReH) or where ReH cannot be
2.2.1 Normal strength steel for ship hull determined, the 0.2 percent proof stress (Rp
structure is to be approved in accordance with 0.2) is to be determined and the material is
requirements given in Section 1. considered to comply with the requirements if
either value meets or exceeds the specified
2.3 Method of Manufacture minimum value for yield strength (Re).

2.3.1 Steel is to be manufactured by the basic 2.6.2 Results obtained from tensile tests are to
oxygen, electric furnace or open hearth comply with the appropriate requirements of
processes or by other processes specially Table 2.6.1.
approved by IRS.
2.6.3 Minimum average energy values are
2.3.2 The definitions of applicable rolling specified for Charpy V-notch impact test
procedures and the schematic diagrams are specimens taken in either the longitudinal or
given in Sec 1. transverse directions. Generally, only
longitudinal test specimens need be prepared
2.3.3 The de-oxidation practice used for each and tested except for special applications where
grade is to comply with the appropriate transverse test specimens may be required.
requirements of Table 2.4.1. Transverse test results are to be guaranteed by
the manufacturer. The tabulated values are for
2.3.4 The rolling practice applied for each grade standard specimens 10 [mm] x 10 [mm]. For
is to comply with the appropriate condition of plate thicknesses lower than 10 [mm], sub-size
supply of Table 2.5.1 specimens may be used with reduced
requirements as follows:
2.4 Chemical composition
Specimen 10 x 7.5 [mm] : 5/6 of tabulated
2.4.1 The chemical composition of samples energy
taken from each ladle of each cast is to be Specimen 10 x 5 [mm] : 2/3 of tabulated
determined by the manufacturer in an energy.
adequately equipped and competently staffed
laboratory and is to comply with appropriate 2.6.4 For impact tests, the average value
requirements of Table 2.4.1. For steel plates obtained from one set of three impact tests is to
and wide flats over 50 [mm] thick, slight comply with the requirements given in Table
deviations in the chemical composition may be 2.6.1. One individual value may be less than the
allowed as approved by IRS. required average value provided that it is not
less than 70 per cent of this average value. See
2.4.2 The manufacturer’s declared analysis will also Chapter 1.
be accepted subject to occasional checks if
required by the surveyor. 2.6.5 Generally, impact tests are not required
when the nominal plate thickness is less than 6
[mm].

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Table 2.4.1 : Deoxidation and chemical composition

Grade A B D E
Deoxidation practice For t ≤ 50 mm For t ≤ 50 mm For t  25 [mm] killed, Killed and fine
Any method Any method grain treated
except rimmed except rimmed
steel1 steel
For t > 50 mm For t > 50 mm For t > 25 mm
Killed Killed Killed and fine grain
treated
Chemical composition per cent 4,7,8 (ladle samples)
Carbon max. 0.212 0.21 0.21 0.18
Manganese min 2.5 x Carbon % 0.803 0.60 0.70
Silicon max 0.50 0.35 0.35 0.10 - 0.35
Phosphorus max 0.035 0.035 0.035 0.035
Sulphur max 0.035 0.035 0.035 0.035
Aluminium - - 0.0155,6 0.0156
(acid soluble min)
Carbon + 1/6 of the manganese content is not to exceed 0.40 per cent
Notes :

1 Grade A sections up to thickness of 12.5 mm may be accepted in rimmed steel subject to the
special approval of IRS.
2 Max. 0.23% for sections.
3 When Grade B steel is impact tested the minimum manganese content may be reduced to 0.60%
4 When any grade of steel is supplied in the thermo-mechanically rolled condition variations in the
specified chemical composition may be allowed or required by IRS.
5 Aluminium is required for thickness above 25 [mm].
6 The total aluminium content may be determined instead of the acid soluble content. In such cases
the total aluminium content is to be not less than 0.020 per cent.
7 IRS may limit the amount of residual/trace elements which may have an adverse effect on the
working and use of the steel, e.g. copper and tin.
8 Where additions of any other element have been made as part of the steelmaking practice, the
content is to be specified.

Table 2.5.1 : Condition of supply for normal strength steel (1)

Grades Thickness Condition of supply

 50 mm Any
A
> 50 mm  100 mm Normalized, controlled rolled or thermo-
mechanically rolled (2)
 50 mm Any
B
> 50 mm  100 mm Normalized, controlled rolled or thermo-
mechanically rolled (2)
 35 mm Any
D
> 35 mm  100 mm Normalized, controlled rolled or thermo-
mechanically rolled (3)
E  100 mm Normalized or thermo-mechanically rolled (3)

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Notes:

1) These conditions of supply and the impact test requirements are summarised in Table 2.5.2

2) Subject to the special approval of IRS, Grades A and B steel plates may be supplied in the as
rolled condition. See 2.14.2.2.

3) Subject to the special approval of IRS, sections in Grade D steel may be supplied in the as rolled
condition provided satisfactory results are consistently obtained from Charpy V-notch impact tests.
Similarly sections in Grade E steel may be supplied in the as rolled or controlled rolled condition.
For the frequency of impact tests see 2.14.3.2 and 2.14.3.3.

Table 2.5.2 : Required condition of supply and number of impact tests for normal strength steels

Condition of supply (batch for impact tests) (1)(2)

Pro- Thickness [mm]
Grade Deoxidation Practice
ducts
10 12.5 20 25 30 35 40 50 100
Rimmed Sections A(-) Not applicable
For t  50 mm Plates A(-) N(-)
A Any method except rimmed TM(-)3
For t > 50 mm CR(50), AR*(50)
Killed Sections A(-) Not applicable
For t  50 mm Plates A(-) A(50) N(50)
Any method except rimmed TM(50)
B CR(25), AR*(25)
For t > 50 mm
Killed Sections A(-) A(50) Not applicable
Killed Plates A(50) Not applicable
D
Sections
D Plates Plates A(50) N(50) N(50)
Killed and fine grain treated CR(50) TM(50)
TM(50) CR(25)
D Sections A(50) N(50) Not applicable
CR(50)
TM(50)
AR*(25)
Killed and fine grain treated Plates N(Each piece)
TM(Each piece)
E Sections N(25) Not applicable
TM(25)
AR*(15), CR*(15)
Remarks:

1. Condition of Supply

A - Any (Not Specified)

N - Normalised Condition
CR - Controlled Rolled Condition
TM - Thermo-Mechanical Rolling
AR* - As Rolled Condition subject to special approval of IRS
CR* - Controlled Rolled Condition subject to special approval of IRS.

2. Number of Impact Tests

One set of impact tests is to be taken from each batch of the specified weight in ( ) in tones or fraction thereof.

3. See Note 5 of Table 2.6.1

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Table 2.6.1 : Mechanical properties for normal strength steels

Impact Test
Yield Elon-
Tensile Average impact energy (J) min.
strengt gation
Gra- strength Test 50 < t  70 70 < t  100
h ReH t  50 mm
de Rm 5.65 S o Temp. mm mm
[N/mm2]
[N/mm2] A5 (%) C Long Trans Long Trans Long Trans
min.
(3) (3) (3) (3) (3) (3)
A +20 - - 34(5) 24(5) 41(5) 27(5)
B 400/520 0 27(4) 20(4) 34 24 41 27
235 22(2)
D (1) -20 27 20 34 24 41 27
E -40 27 20 34 24 41 27
Notes:

1) For all thicknesses of Grade A sections the upper limit for the specified tensile strength range may
be exceeded at the discretion of IRS.

2) For full thickness flat tensile test specimens with a width of 25 mm and a gauge length of 200 mm
the elongation is to comply with the following minimum values:

>5 > 10 > 15 > 20 > 25 > 30 > 40

Thickness [mm]
5  10  15  20  25  30  40  50
Elongation 14 16 17 18 19 20 21 22
3) See 2.6.3.

4) Charpy V-notch impact tests are generally not required for Grade B steel with thickness of 25 mm or
less.

5) Impact tests for Grade A over 50 mm thick are not required when the material is produced using fine
grain practice and furnished normalised. TM rolling may be accepted without impact testing at the
discretion of IRS.

2.7 Surface Quality 2.7.2.1 The surface quality inspection method is

to be in accordance with recognized national or
2.7.1 The steel is to be free from surface defects international standards agreed between
prejudicial to the use of the material for the purchaser and manufacturer, accepted by IRS.
intended application. The finished material is to
have a surface quality in accordance with a 2.7.2.2 If agreed between the manufacturer and
recognized standard such as EN 10163 parts 1, purchaser, steel may be ordered with improved
2 and 3, or an equivalent standard accepted by surface finish over and above these
IRS, unless otherwise specified in this section. requirements.

2.7.2 The responsibility for meeting the surface 2.7.3 Acceptance Criteria
finish requirements rests with the manufacturer
of the material, who is to take the necessary 2.7.3.1 Imperfections
manufacturing precautions and is to inspect the
products prior to delivery. At that stage, 2.7.3.1.1 Imperfections of a harmless nature, for
however, rolling or heat treatment scale may example pitting, rolled-in scale, indentations, roll
conceal surface discontinuities and defects. If, marks, scratches and grooves, regarded as
during the subsequent descaling or working being inherent of the manufacturing process, are
operations, the material is found to be defective, permissible irrespective of their number,
IRS may require materials to be repaired or provided the maximum permissible limits of
rejected. Class A of EN 10163-2 or limits specified in a
recognized equivalent standard accepted by

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IRS, are not exceeded and the remaining plate
or wide flat thickness remains within the average 2.7.4.2 Welding repair
allowable minus thickness tolerance specified in
Sec 1, 1.4. Total affected area with imperfection 2.7.4.2.1 Weld repair procedures and the
not exceeding the specified limits are not to method are to be reported and be approved by
exceed 15 % of the total surface in question. the IRS. Repair of defects such as unacceptable
imperfections, cracks, shells or seams are to be
2.7.3.2 Defects followed by magnetic particle or liquid penetrant
testing. Local defects which cannot be repaired
2.7.3.2.1 Affected areas with imperfections with by grinding as stated in 2.7.4.1 may be repaired
a depth exceeding the limits of Class A of EN by welding with the agreement of IRS subject to
10163-2 or the maximum permissible limits the following conditions:
specified in a recognized equivalent standard
accepted by IRS, are to be repaired irrespective (a) Any single welded area is not to
of their number. Cracks, injurious surface flaws, exceed 0.125 [m2] and the sum of all
shells (over lapping material with non-metallic areas is not to exceed 2% of the surface
inclusion), sand patches, laminations and sharp side in question.
edged seams (elongated defects) visually
evident on surface and/or edge of plate are (b) The distance between two welded
considered defects, which would impair the end areas is not to be less than their
use of the product and which require rejection or average width.
repair, irrespective of their size and number.
(c) The weld preparation is not to
2.7.4 Repair reduce the thickness of the product
below 80% of the nominal thickness.
2.7.4.1 Grinding repair For occasional defects with depths
exceeding the 80% limit, special
2.7.4.1.1 Grinding may be applied provided all consideration at the Surveyor’s
the conditions below are adhered to: discretion will be necessary.

(a) The nominal product thickness will (d) If weld repair depth exceeds 3 [mm],
not be reduced by more than 7% or 3 UT may be requested by IRS. If
mm, whichever is the less. required, UT is to be carried out in
accordance with an approved
(b) Each single ground area does not procedure.
exceed 0.25 [m2].
(e) The repair is to be carried out by
(c) All ground areas do not exceed 2% qualified welders using an approved
of the total surface in question. procedure for the appropriate steel
grade. The electrodes are to be of low
(d) Ground areas lying in a distance less hydrogen type and are to be dried in
than their average breadth to each other accordance with the manufacturer’s
are to be regarded as one single area. requirements and protected against re-
humidification before and during
(e) Ground areas lying opposite each welding.
other on both surfaces are not to
decrease the product thickness by 2.7.5 The surface quality and condition
values exceeding the limits as indicated requirement herein are not applied to products
in (a). in forms of bars and tubulars, which will be
subject to manufacturers’ conformance
Defects or unacceptable imperfections are to be standards.
completely removed by grinding and the
remaining plate or wide flat thickness is to 2.8 Internal soundness
remain within the average allowable minus
thickness tolerance specified in Sec.1, 1.4. The 2.8.1 If plates and wide flats are ordered with
ground areas are to be a smooth transition to ultrasonic inspection, this is to be made in
the surrounding surface of the product. accordance with an accepted standard at the
Complete elimination of the defect is to be discretion of IRS.
verified by magnetic particle or by liquid
penetrant testing.

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2.8.2 Verification of internal soundness is the 2.12 Test Material

responsibility of the manufacturer. The
acceptance of internal soundness by surveyor 2.12.1 Definitions
does not absolve the manufacturer from this
responsibility. 2.12.1.1 Refer to Ch1 for the definitions of piece
and batch.
2.9 Tolerances
2.12.2 Test Samples
2.9.1 Unless otherwise agreed or specially
required the thickness tolerances as per Sec.1, 2.12.2.1 Refer to Sec 1, for the requirements
1.4 are applicable. related to test samples.

2.10 Identification of Materials 2.13 Mechanical Test specimens

2.10.1 The steelmaker is to adopt a system for 2.13.1 Tensile Test Specimens. The dimensions
the identification of ingots, slabs and finished of the tensile test specimens are to be in
pieces which will enable the material to be accordance with Ch.2. Generally, for plates,
traced to its original cast. wide flats and sections flat test specimens of full
product thickness are to be used. Round test
2.10.2 The Surveyor is to be given full facilities specimens may be used when the product
for so tracing the material when required. thickness exceeds 40 [mm] or for bars and other
similar products. Alternatively, for small sizes of
2.11 Testing and Inspection bars, etc. test specimens may consist of a
suitable length of the full cross section of the
2.11.1 Facilities for Inspection product.

2.11.1.1 The manufacturer is to afford the 2.13.2 Impact Test Specimens. The impact test
Surveyor all necessary facilities and access to specimens are to be of the Charpy V-notch type
all relevant parts of the works to enable him to cut with their edge within 2 [mm] from the “as
verify that the approved process is adhered to, rolled” surface with their longitudinal axes either
for the selection of test materials, and the parallel (indicated “Long” in Table 2.6.1) or
witnessing of tests, as required by the Rules, transverse (indicated "Trans" in Tables 2.6.1) to
and for verifying the accuracy of the testing the final direction of rolling of the material. The
equipment. notch is to be cut in a face of the test specimen
which was originally perpendicular to the rolled
2.11.2 Testing Procedures surface. The position of the notch is not to be
nearer than 25 [mm] to a flame cut or sheared
2.11.2.1 The prescribed tests and inspections edge (see also 2.6.3). Where the product
are to be carried out at the place of manufacture thickness exceeds 40 [mm], the impact test
before dispatch. The test specimens and specimens are to be taken with their longitudinal
procedures are to be in accordance with Ch.2. axis at a quarter thickness position.
All the test specimens are to be selected and
stamped by the Surveyor and tested in his 2.14 Number of Test Specimens
presence, unless otherwise agreed.
2.14.1 Number of Tensile Tests
2.11.3 Through Thickness Tensile Tests
2.14.1.1 For each batch presented. except
2.11.3.1 If plates and wide flats with thickness of where specially agreed by IRS. one tensile test
15 [mm] and over are ordered with through is to be made from one piece unless the weight
thickness properties, the through thickness of finished material is greater than 50 tonnes in
tensile test in accordance with Sec.8 is to be which case one extra test piece is to be made
carried out. from a different piece from each 50 tonnes or
fraction thereof. Additional tests are to be made
2.11.4 Dimensions for every variation of 10 [mm] in thickness of
plate or diameter of products from the same
2.11.4.1 Verification of dimensions are the cast. For sections the thickness to be
responsibility of the steel maker. The considered is the thickness of the product at the
acceptance by Surveyor does not absolve the point at which samples are taken for mechanical
steel maker from this responsibility. tests.

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2.14.2 Number of Impact Tests (except for 2.14.2.3 The piece selected for the preparation
Grade E) of the test specimens is to be the thickest in
each batch.
2.14.2.1 For each batch presented, except
where specially agreed by IRS at least one set 2.14.3 Number of Impact Tests (for Grade E)
of three Charpy V-notch test specimens is to be
made from one piece unless the weight of 2.14.3.1 For steel plates supplied in the
finished material is greater than 50 tonnes in normalized or TM condition, one set of impact
which case one extra set of three test test specimens is to be taken from each piece.
specimens is to be made from a different piece
from each 50 tonnes or fraction thereof. The 2.14.3.2 For sections, one set of impact tests is
piece selected for the preparation of test to be taken from each batch of 25 tonnes or
specimen is to be the thickest of each batch. fraction thereof.
Where steel plates except for Grade 'A' steel
over 50 [mm] in thickness is supplied in the 2.14.3.3 When, subject to the special approval
controlled rolled condition, the frequency of of IRS, sections are supplied in the as-rolled or
impact test is to be made from a different piece controlled rolled condition.one set of impact
from each 25 tonnes or fraction thereof. tests is to be taken from each batch of 15
tonnes or fraction thereof.
2.14.2.2 When subject to the special approval of
IRS, material is supplied in the as rolled 2.14.3.4 For 2.14.3.2 and 2.14.3.3 above the
condition the frequency of impact tests is to be piece selected for the preparation of the test
increased to one set from each batch of 25 specimens is to be the thickest in each batch.
tonnes or fraction thereof. However, for Grade
'A' steel over 50 [mm] thickness when supplied 2.15 Retest Procedures
in the "as rolled" condition, one set of three
charpy V-notch test specimens may be taken 2.15.1 Retest procedures are to be as per the
from each batch of 50 tonnes or fraction thereof. requirements provided in Chapter 1.

Section 3

Higher Strength Steels for Ship Structures

3.1 General 3.1.4 Provision is made for three strength levels

(315, 355 and 390 N/mm2) each subdivided into
3.1.1 Requirements of this section is applicable four grades, AH, DH, EH and FH based on
to weldable higher strength hot-rolled steel impact test temperature .
plates, wide flats, sections and bars intended for
use in hull construction. The additional requirements for high strength
plates having specified minimum yield point of
3.1.2 The requirements of this section are 460 [N/mm2] with thickness over 50 [mm] and
primarily intended to apply to plates and wide not greater than 100 [mm] for use in longitudinal
flats not exceeding 100 [mm] in thickness in structural members in the upper deck region of
general, and sections and bars not exceeding container ships (such as hatch side coaming,
50 [mm] in thickness. For greater thickness, hatch coaming, hatch coaming top and attached
these requirements may be applied with certain longitudinals) and denoted by Grade EH47 are
variations, as may be agreed by IRS. also given in this section.

3.1.3 Steel differing in chemical composition, Brittle Crack Arrest Steels: Brittle crack arrest
deoxidation practice, heat treatment or steels are defined as steel plate with the
mechanical properties may be accepted, subject specified brittle crack arrest properties
to special approval by IRS. Such steel is to be measured by either the brittle crack arrest
given special designation. toughness Kca or Crack Arrest Temperature
(CAT). Additional requirements for brittle crack
arrest steels are specified in Section 10. Brittle

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crack arrest steels are to be used for container 3.3 Method of Manufacture
ships, as indicated in Pt. 5, Ch. 5 of the Rules.
3.3.1 Steel is to be manufactured by the basic
3.1.5 Requirements of this section also apply to oxygen, electric furnace or open hearth
high strength Corrosion Resistant steels when processes or by other processes specially
such steel is used as the alternative means of approved by IRS.
corrosion protection for cargo oil tanks as
specified in the performance standard MSC.289 3.3.2 The definitions of applicable rolling
(87) of Regulation 3-11, Part A-1, Chapter II-1 of procedures and the schematic diagrams are
the SOLAS Convention (Corrosion protection of given in Sec 1.
cargo oil tanks of crude oil tankers). Corrosion
Resistant steels as defined within this section, 3.3.3 The deoxidation practice used for each
are steels whose corrosion resistance grade is to comply with the appropriate
performance in the bottom or top of the internal requirements of Table 3.4.1.
cargo oil tank is tested and approved to satisfy
the requirements in MSC.289 (87) in addition to 3.3.4 The rolling practice applied for each grade
other relevant requirements for hull structural is to comply with the appropriate condition of
steels, structural strength and construction. It is supply of Table 3.5.1
not intended that such steels be used for
corrosion resistant applications in other areas of 3.4 Chemical composition
a vessel that are outside of those specified in
the performance standard MSC.289 (87) of 3.4.1 The chemical composition of samples
Regulation 3-11, Part A-1, Chapter II-1 of the taken from each ladle of each cast is to be
SOLAS Convention. These requirements apply determined by the manufacturer in an
to plates, wide flats, sections and bars in all adequately equipped and competently staffed
grades up to a maximum thickness of 50 [mm]. laboratory and is to comply with appropriate
requirements of Table 3.4.1. For steel plates
3.2 Approval and wide flats over 50 [mm] thick, slight
deviations in the chemical composition may be
3.2.1 Higher strength steel for ship hull structure allowed as approved by IRS.
is to be approved in accordance with
requirements given in Section 1. The chemical composition of EH 47 steel plates
would be specially considered.
3.2.2 It should be noted that when fatigue
loading is present, the effective fatigue strength 3.4.2 The manufacturer’s declared analysis will
of a welded construction of higher strength be accepted subject to occasional checks if
steels may not be greater than that of a required by the surveyor.
construction fabricated from the normal strength
steels. Precautions against corrosion fatigue 3.4.3 When required, the carbon equivalent
may also be necessary. value is to be calculated from the ladle analysis
using the following formula.
Note: Before subjecting steels produced by
thermo-mechanical rolling to further heating for Mn Cr  Mo  V Ni  Cu
Carbon eq.  C    %
forming or stress relieving or using high heat- 6 5 15
input welding, special consideration must be
given to the possibility of a consequent Note: This formula is applicable only to steels
reduction in mechanical properties. which are basically of the carbon manganese
type and gives a general indication of the
weldability of the steel.

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Table 3.4.1 : Chemical composition and deoxidation practice for higher strength steels

AH32/DH32/EH32 FH32
Grade1) AH36/DH36/EH36 FH36 EH47
AH40/DH40/EH40 FH40
Deoxidation
Fully killed and fine grain refined
practice
Chemical Composition per cent (Ladle sample)5),6)

C max. 0.18 0.16 0.18

Mn 0.90 - 1.602) 0.90 - 1.60 0.9 – 2.00
Si max. 0.50 0.50 0.55
P max. 0.035 0.025 0.020
S max. 0.035 0.025 0.020

Grain refining elements5)

Al (acid
0.0153),4)
soluble)
min.
Nb
0.02 - 0.054)
V
0.05 - 0.104)
Ti max.
0.02
Total (Nb +
0.12 max.
V + Ti)
Residual elements
0.35
Cu max. 0.35 0.35
0.20
Cr max. 0.20 0.25
0.80
Ni max. 0.40 1.0
0.08
Mo max. 0.08 0.08
0.009 (0.012 if Al is
N max. - -
present)
Notes:

1) The number following the grade designation indicates the yield point to which the steel is ordered or produced in
[Kg/mm2].

2) For thickness upto and including 12.5 [mm] the minimum manganese content may be reduced to 0.70 percent.

3) The total aluminium content may be determined instead of the acid soluble content. In such cases the total
aluminium content is to be not less than 0.020 percent

4) The steel is to contain aluminium, niobium, vanadium or other suitable grain refining elements, either single or in
combination. When used singly the steel is to contain the specified minimum content of the grain refining
element. When used in combination, the specified minimum content of a fine graining element is not applicable.

5) When any grade of higher strength steel is supplied in the thermo-mechanically rolled condition variations in the
specified chemical composition may be allowed or required by IRS

6) Where additions of any other element have been made as part of the steel making practice, the content is to be
indicated.

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3.4.4 For TM (TMCP) steels the following Mn Cr  Mo  V Ni  Cu

special requirements apply: Carbon eq.  C    %
6 5 15
ii) Other means such as cold cracking
i) The carbon equivalent value is to be susceptibility Pcm (in %), may be considered
calculated from the ladle analysis using the instead of the carbon equivalent for evaluating
following formula and to comply with the the weldability.
requirements of the following table:
Si Mn Cu Ni Cr Mo V
Carbon equivalent for higher strength steels Pcm  C         5B
upto 100 mm in thickness produced by TM 30 20 20 60 20 15 10
Carbon equivalent
Grade Max. (%)1) 3.4.5 The carbon equivalent of EH47 grade steel
t  50 50 < t  100 calculated as per 3.4.3 is not to exceed 0.49%.
AH32, DH32, The cold cracking susceptibility Pcm calculated
0.36 0.38 using the formula mentioned in 3.4.4.(ii) is not to
EH32, FH32
AH36, DH36, exceed 0.22%.
0.38 0.40
EH36, FH36
AH40, DH40, 3.5 Condition of supply
0.40 0.42
EH40, FH40
EH47 NA 0.49 3.5.1 All materials are to be supplied in a
t = thickness [mm] condition complying with the requirements given
in Table 3.5.1.
Note:

1) It is a matter for the manufacturer and

shipbuilder to mutually agree in individual cases
as to whether they wish to specify a more
stringent carbon equivalent.

Table 3.5.1 : Condition of supply for Higher strength steel 1)

Grades Grain Refining Thickness Condition of supply

Elements Used
≤ 12.5 mm Any
Nb and/or V Normalized, controlled rolled or thermo-
> 12.5 mm ≤ 100 mm
mechanically rolled (3)
A32 ≤ 20 mm Any
A36 Any, as rolled subject to special approval
Al alone > 20 mm ≤ 35 mm
of IRS (2)
or with Ti
Normalized, controlled rolled or thermo-
> 35 mm ≤ 100 mm
mechanically rolled (3)
≤ 12.5 mm Any
Normalized, controlled rolled or thermo-
> 12.5 mm ≤ 50 mm
A40 Any mechanically rolled
Normalized, thermo-mechanically rolled or
> 50 mm ≤ 100 mm
quenched and tempered
≤ 12.5 mm Any
Nb and/or V Normalized, controlled rolled or thermo-
> 12.5 mm ≤ 100 mm
mechanically rolled (3)
D32 ≤ 20 mm Any
D36 Any, as rolled subject to special approval
Al alone > 20 mm ≤ 25 mm
of IRS (2)
or with Ti
Normalized, controlled rolled or thermo-
> 25 mm ≤ 100 mm
mechanically rolled (3)

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Table 3.5.1 : (Contd.)

Grades Grain Refining Thickness Condition of supply

Elements Used
Normalized, controlled rolled or thermo-
≤ 50 mm
mechanically rolled
D40 Any
Normalized, thermo-mechanically rolled or
> 50 mm ≤ 100 mm
quenched and tempered
Normalized or thermo-mechanically rolled
E32 ≤ 50 mm (3)
Any
E36
> 50 mm ≤ 100 mm Normalized, thermo-mechanically rolled
Normalized, thermo-mechanically rolled or
≤ 50 mm
quenched and tempered
E40 Any
Normalized, thermo-mechanically rolled or
> 50 mm ≤ 100 mm
quenched and tempered
Normalized, thermo-mechanically rolled or
F32 ≤ 50 mm
quenched and tempered (4)
F36 Any
Normalized, thermo-mechanically rolled or
F40 > 50 mm ≤ 100 mm
quenched and tempered
Notes:

(1) These conditions of supply and the requirements for impact tests are summarised in Table
3.5.2.
(2) The frequency of impact tests is to be in accordance with 3.14.2 (ii).
(3) Subject to the special approval of IRS, sections in Grades AH32, AH36, DH32 and DH36 steels
may be supplied in the as rolled condition provided satisfactory results are consistently
obtained from Charpy V-notch impact tests. Similarly sections in Grades EH32 and EH36
steels maybe supplied in the as rolled or controlled rolled condition. The frequency of impact
tests is to be in accordance with 3.14.2 (ii) and 3.14.2 (iii) respectively.
(4) Subject to the special approval of IRS, sections in Grades FH32 and FH36 steels may be
supplied in the controlled rolled condition. The frequency of impact tests is to be in accordance
with 3.14.3 (iii).

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Table 3.5.2 : Required condition of supply and number of impact tests for higher strength steels

Condition of supply (batch for impact tests) (1)(2)

Deoxi- Grain
Pro- Thickness [mm]
Grade dation Refining
ducts
Practice Elements 10 12.5 20 25 30 35 40 50 100
Plates A(50) N(50) N(50), CR(25),
CR(50),TM(50) TM(50)
Nb and/or
V Sections A(50) N(50) Not applicable
CR(50),TM(50)
AH32 AR*(25)
Killed and Plates A(50) AR*(25) Not applicable
AH36
fine grain
treated N(50), CR(50) N(50), CR(25)
Al alone or TM(50) TM(50)
with Ti Sections A(50) N(50) Not applicable
CR(50)
TM(50)
AR*(25)
Any Plates A(50) N(50) N(50)
CR(50) TM(50)
TM(50) QT(Each
Killed and
length as
AH40 fine grain heat treated)
treated Sections A(50) N(50) Not applicable
CR(50)
TM(50)
Plates A(50) N(50) N(50), CR(25),
CR(50),TM(50) TM(50)
Nb and/or
V Sections A(50) N(50) Not applicable
CR(50),TM(50)
AR*(25)
Killed and Plates A(50) AR*(25) Not applicable
DH32
fine grain
DH36 N(50), CR(50) N(50), CR(25)
treated
Al alone or TM(50) TM(50)
with Ti Sections A(50) N(50) Not applicable
CR(50)
TM(50)
AR*(25)
Plates N(50) N(50)
CR(50) TM(50)
TM(50) QT(Each
Killed and length as
DH40 fine grain Any heat
treated treated)
Sections N(50) Not applicable
CR(50)
TM(50)
Plates N(Each piece)
TM(Each piece)
EH32 Killed and
EH36 fine grain Any Sections N(25) Not applicable
TM(25)
treated AR*(15)
CR*(15)
Killed and Plates N(Each piece)
fine grain TM(Each piece)
treated QT(Each length as heat treated)
EH40 Any
Sections N(25) Not applicable
TM(25)
QT(25)

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Table 3.5.2 : (Contd.)

Grade Deoxi- Grain Products Condition of supply (Batch for impact tests (1)(2)
dation refining Thickness [mm]
practice elements
10 12.5 20 25 30 35 40 50 100
N(Each piece)
Plates TM(Each piece) Not applicable
Killed and QT(Each length as heat treated)
FH32
fine grain Any N(25)
FH36 treated TM(25)
Section Not applicable
QT(25)
CR*(15)
N(Each piece)
Plates TM(Each piece) Not applicable
Killed and QT(Each length as heat treated)
FH40 fine grain Any
treated N(25)
Sections TM(25) Not applicable
QT(25)
Remarks
1. Condition of Supply
A - Any (Not Specified)
N - Normalised Condition
CR - Controlled Rolled Condition
TM - Thermo-Mechanical Rolling
QT - Quenched and Tempered Condition
AR* - As Rolled Condition subject to special approval of IRS
CR* - Controlled Rolled Condition subject to special approval of IRS.
2. Number of Impact Tests
One set of impact tests is to be taken from each batch of the "specified weight" in ( ) in tones or fraction
thereof.
For Grades A32 and A36 steels charpy impact tests are not generally required provided that satisfactory
results are obtained from occasional check tests selected by the Surveyor.

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3.6 Mechanical Properties either value meets or exceeds the specified

minimum value for yield strength (Re).
3.6.1 For tensile test either the upper yield
stress (ReH) or where ReH cannot be 3.6.2 Results obtained from tensile tests are to
determined, the 0.2 percent proof stress (Rp comply with the appropriate requirements of
0.2) is to be determined and the material is Table 3.6.1.
considered to comply with the requirements if

Table 3.6.1 : Mechanical properties for higher strength steels

Impact Test
Yield
Tensile Elon- Average impact energy (J) min.
stren-
strengt gation Test 50 < t  70 70 < t  100
Grade gth ReH t  50 mm
h Rm 5.65 So Temp. mm mm
[N/mm2]
[N/mm2] A5 (%) C Long Trans Long Trans Long Trans
min.
(2) (2) (2) (2) (2) (2)
AH32 315 440/570 22(1) 0 31(3) 23(3) 38 26 46 31
DH32 -20 31 22 38 26 46 31
EH32 -40 31 22 38 26 46 31
FH32 -60 31 22 38 26 46 31
AH36 355 490/630 21(1) 0 34(3) 24(3) 41 27 50 34
DH36 -20 34 24 41 27 50 34
EH36 -40 34 24 41 27 50 34
FH36 -60 34 24 41 27 50 34
AH40 390 510/660 20(1) 0 39 27 46 31 55 37
DH40 -20 39 27 46 31 55 37
EH40 -40 39 27 46 31 55 37
FH40 -60 39 27 46 31 55 37
t = thickness [mm]

NOTES:

1) For full thickness flat tensile test specimens with a width of 25 [mm] and a gauge length of 200
[mm] the elongation [%] is to comply with the following minimum values:

Thickness [mm]
>5 > 10 > 15 > 20 > 25 > 30 > 40
Grade
5  10  15  20  25  30  40  50
AH32, DH32, EH32 & FH32 14 16 17 18 19 20 21 22

AH36, DH36, EH36 & FH36 13 15 16 17 18 19 20 21

AH40, DH40, EH40 & FH40 12 14 15 16 17 18 19 20

2) See 3.6.3.

3) For Grades AH32 and AH36 steels a relaxation in the number of impact tests for acceptance
purposes may be permitted by special agreement with IRS provided that satisfactory results are
obtained from occasional check tests.

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Table 3.6.2 : Conditions of supply, grade and mechanical properties for EH47 steel plates

Supply Grade Mechanical Properties Impact Test

Condition
Yield Tensile Elongation Test Average Impact Energy [J]
Strength Strength (%) min. Temp. min.
[N/mm2]min [N/mm2] (oC) 50<t≤ 70<t≤8 85<t≤
70 5 100
TMCP EH 47 460 570/720 17 -40oC 53 64 75

Note : t: Thickness [mm]

1). The additional requirements for EH47 steel with brittle crack arrest properties are specified in
Section 10.

3.6.3 Minimum average energy values are 3.9 Tolerances

specified for Charpy V-notch impact test
specimens taken in either the longitudinal or 3.9.1 Requirements of 2.9 are applicable.
transverse directions. Generally, only
longitudinal test specimens need be prepared 3.10 Identification of Materials
and tested except for special applications where
transverse test specimens may be required. 3.10.1 Requirements of 2.10 are applicable
Transverse test results are to be guaranteed by
the manufacturer. The tabulated values are for 3.11 Testing and Inspection
standard specimens 10 [mm] x 10 [mm]. For
plate thicknesses lower than 10 [mm], sub-size 3.10.1 Requirements of 2.11 are applicable
specimens may be used with reduced
requirements as follows : 3.12 Test Material

Specimen 10 x 7.5 [mm] : 5/6 of tabulated 3.12.1 Requirements of 2.12 are applicable
energy
Specimen 10 x 5 [mm] : 2/3 of tabulated 3.13 Mechanical tests specimens
energy.
3.13.1 Tensile Test Specimens. The dimensions
3.6.4 For impact tests, the average value of the tensile test specimens are to be in
obtained from one set of three impact tests is to accordance Ch.2. Generally for plates, wide flats
comply with the requirements given in Table and sections flat test specimens of full product
3.6.1. One individual value may be less than the thickness are to be used. Round test specimens
required average value provided that it is not may be used when the product thickness
less than 70 per cent of this average value. See exceeds 40 [mm] or for bards and other similar
also Chapter 1. products. Alternatively for small sizes of bars,
etc. test specimens may consist of a suitable
3.6.5 Generally, impact tests are not required length of the full cross section of the product.
when the nominal plate thickness is less than 6
[mm]. 3.13.2 Impact Test Specimens. The impact test
specimens are to be of the Charpy V-notch type
3.7 Surface Quality cut with their edge within 2 [mm] from the “as
rolled” surface with their longitudinal axes either
3.7.1 Requirements of 2.7 are applicable. parallel (indicated “Long” in Table 3.6.1) or
transverse (indicated "Trans" in Table 3.6.1) to
3.8 Internal Soundness the final direction of rolling of the material. The
notch is to be cut in a face of the test specimen
3.8.1 Requirements of 2.8 are applicable. which was originally perpendicular to the rolled
surface. The position of the notch is not to be
nearer than 25 [mm] to a flame cut or sheared

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edge (see also 3.6.3). Where the product 3.14.3 Number of Impact Tests (Grades EH32,
thickness exceeds 40 [mm], the impact test EH36, EH40, FH32, FH36 and FH40):
specimens are to be taken with their longitudinal
axis at a quarter thickness position. i) For plates supplied in the normalized or TM
condition one set of three Charpy V-notch
3.14 Number of Test Specimens impact test specimens is to be taken from each
piece. For quenched and tempered steel plates
3.14.1 Number of Tensile Tests. For each batch one set of impact test specimens is to be taken
presented, except where specially agreed by from each length as heat treated.
IRS, one tensile test is to be made from one
piece unless the weight of finished material is ii) For sections one set of impact tests is to be
greater than 50 tonnes in which case one extra taken from each batch of 25 tonnes or fraction
test piece is to be made from a different piece thereof.
from each 50 tonnes or fraction thereof.
Additional tests are to be made for every iii) When, subject to special approval of IRS,
variation of 10 [mm] in thickness of plate or sections other than Grades EH40 and FH40 are
diameter of products from the same cast. For supplied in the as-rolled or controlled rolled
sections, the thickness to be considered is the condition, one set of impact tests is to be taken
thickness of the product at the point at which from each batch of 15 tonnes or fraction thereof.
samples are taken for mechanical tests.
iv) For (ii) and (iii) above the piece selected for
3.14.2 Number of Impact Tests (except for the preparation of test specimens is to be the
Grades EH32, EH36, EH40, EH47, FH32, FH36 thickest in each batch.
and FH40):
3.15 Manufacturing approval scheme for
i) Except where otherwise specified or specially EH47 steels
agreed by IRS, for each batch presented, at
least one set of three Charpy V-notch impact 3.15.1 Approval scheme
test specimen is to be made from one piece
unless the weight of finished material is greater .1 Manufacturing approval scheme for EH47
than 50 tonnes, in which case one extra set of steels is to be in accordance with Part 2 of the
three test specimens is to be made from a IRS Classification Note: ‘Approval Scheme for
different piece from each 50 tonnes or fraction the Manufacturing Process of Normal and
thereof. When steel plates over 50 [mm] in Higher Strength Hull Structural Steels’, unless
thickness is supplied in the controlled rolled otherwise specified in this sub-section.
condition, the frequency of impact test is to be
made from a different piece from each 25 3.15.2 Approval tests
tonnes or fraction therof.
.1 Extent of Approval tests : Cl. 2.1 (c) and (d) of
ii) For steel plates of Grades AH40 and DH40 Part 2 of subject Classification Note are not to
with thickness over 50 [mm] in normalized or TM be applied to manufacturing approval of EH47
condition, one set of impact test specimens is to steels.
be taken from each batch of 50 tonnes or
fraction thereof. For those in QT condition, one .2 Type of tests
set of impact test specimens is to be taken from
each length as heat treated. (a) Brittle fracture initiation test: Deep notch test
or Crack Tip Opening Displacement (CTOD) test
iii) When, subject to special approval of IRS, is to be carried out. The test method is to be
material is supplied in the as rolled condition, acceptable to IRS.
the frequency of impact tests is to be increased
to one set from each batch of 25 tonnes or (b) Y-groove weld cracking test (Hydrogen crack
fraction thereof. test): The test method is to be in accordance
with recognized national standards such as JIS
iv) The piece selected for the preparation of test Z 3158-2016 or CB/T 4364-2013.
specimens is to be the thickest in each batch.

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In addition to the requirements specified in (a)
and (b) above, the approval tests specified in 3.16 Retest Procedures
Part 2 of the IRS Classification Note: ‘Approval
Scheme for the Manufacturing Process of 3.16.1 Retest procedures are to be as per the
Normal and Higher Strength Hull Structural requirements provided in Chapter 1.
Steels’, are also to be carried out. Additional
tests may be required when deemed necessary
by IRS.

Section 4

High Strength Steels for Welded Structures

4.1 General
4.1.6 Steels differing in chemical composition,
4.1.1 These requirements apply to hot-rolled, deoxidation practice, delivery condition and
fine-grain, weldable high strength structural mechanical properties may be accepted, subject
steels, intended for use in marine and offshore to the special approval of the IRS. Such steels
structural applications. These requirements do are to be given a special designation.
not apply to steels intended for hull structure of
commercial ships whose requirements are 4.2 Approval
specified in previous sections.
4.2.1 For applications subjected to
4.1.2 The steel covered by the scope of these Classification, all steels are to be manufactured
requirements are specified in yield strength at steel works which have been approved by
levels of 420, 460, 500, 550, 620, 690,890 and IRS for the type and grade of steel which is
960 [N/mm2]. For each yield strength level being supplied. The procedure for approval is
grades AH, DH, EH and FH are specified, based available in Classification Note “Manufacturing
on the impact test temperature, except for yield Approval Scheme of High Strength Steels for
strength level of 890 and 960 [N/mm2] for which Welded Structures”. Also refer Chapter 1,
grade F is not applicable. The full list of grades Section 1, Cl. 1.3.2.
are:
4.2.2 It is the steelmaker’s responsibility to
AH420 DH420 EH420 FH420 assure that effective quality, process and
AH460 DH460 EH460 FH460 production controls during manufacturing are
AH500 DH500 EH500 FH500 adhered to within the manufacturing
AH550 DH550 EH550 FH550 specification. The manufacturing specification is
AH620 DH620 EH620 FH620 to be submitted to IRS at the time of initial
AH690 DH690 EH690 FH690 approval.
AH890 DH890 EH890
AH960 DH960 EH960 4.2.3 Where non-conformities arise, the
manufacturer is to identify the root cause and
4.1.3 Steels covered by the scope may be establish countermeasures to prevent its
delivered in Normalized (N)/Normalized rolled recurrence. The non-conformities and the
(NR); Thermo-mechanical controlled rolled (TM) countermeasures are to be documented and
or Quenched and Tempered (QT) condition. reported to IRS.

Note: TM is a generic delivery condition that 4.2.4 When the semi-finished products were not
may not include accelerated cooling, and may or manufactured by the approved manufacturer of
may not include direct quenching followed by the finish rolled and heat treated products, the
tempering after TM-rolling. manufacturer of the semi-finished product is
also to be subject to approval by IRS.
4.1.4 Product forms include plates, wide flats,
sections bars and seamless tubulars. Note 1: The attention of the users must be
drawn to the fact that when fatigue loading is
4.1.5 Steels with a thickness beyond the present, the effective fatigue strength of a
maximum thicknesses as given in Table 4.5.3 welded joint of high strength steel may not be
may be approved at the discretion of the IRS.

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greater than that of a welded joint in normal for the initial approval tests, either from the
strength steels. ladle, the tundish or the mould in the case of
continuous casting. The aim analysis is to be in
Note 2: Before subjecting steels produced by accordance with the manufacturing
thermos-mechanical rolling or quenched and specification. All the elements listed in the Table
tempered after rolling to further heating for 4.4.1 are to be reported.
forming or stress relieving, or using high heat-
input welding, special consideration must be 4.4.2 Elements used for alloying, nitrogen
given to the possibility of a consequent binding, and fine grain treatment, and as well as
reduction in mechanical properties the residual elements are to be as detailed in
the manufacturing specification, e.g. When
4.3 Method of manufacture boron is deliberately added for enhancement of
hardenability of the steels, the maximum content
4.3.1 Steel making process of the boron content is not to be higher than
0.005%; and the analysis result is to be
4.3.1.1 The steel is to be manufactured by the reported.
basic oxygen, basic electric arc furnace or by
processes specially approved by IRS. 4.4.3 The carbon equivalent value is to be
calculated from the ladle analysis. Maximum
4.3.1.2 Vacuum degassing is to be used for any values are specified in Table 4.4.2.
of the following:
a) For all steel grades the following
a) all steels with enhanced through-thickness formula of IIW may be used:
properties, and

b) all steels of grade H690, H890 and H960.

4.3.2 Deoxidation
b) For steel grades H460 and higher, CET
4.3.2.1 The steel shall be fully killed . may be used instead of Ceq at the
discretion of the manufacturer, and is to
4.3.3 Grain size be calculated according to the following
formula:
4.3.3.1 The steel is to be fine grain treated, and
is to have a fine grain structure. The fine grain
practice is to be as detailed in the manufacturing
specification.
Note: The CET is included in the
Note: A fine grain structure has an equivalent standard EN 10011-2:2001 used as one
index ≥ 6 determined by micrographic of the parameters for pre-heating
examination in accordance with ISO 643 or temperature determination which is
alternative test method. necessary for avoiding cold cracking.

4.3.4 Nitrogen control c) For TM and QT steels with carbon

content not more than 0.12%, the cold
4.3.4.1 The steels are to contain nitrogen cracking susceptibility Pcm for
binding elements as detailed in the evaluating weldability may be used
manufacturing specification. Also see note 4 in instead of carbon equivalent of Ceq or
Table 4.4.1. CET at manufacturer’s discretion and is
to be calculated using the following
4.4 Chemical composition formula:

4.4.1 The chemical composition is to be Si Mn Cu Ni Cr Mo V

Pcm  C         5B
determined by the steel maker, in an adequately 30 20 20 60 20 15 10
equipped competently staffed laboratory.The
method of sampling is to follow that carried out

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Table 4.4.1 : Chemical composition

Delivery condition1) N/NR TM QT
AH420 EH420 AH420 EH420 AH420 EH420
DH420 EH460 DH420 FH420 DH420 FH420
AH460 AH460 EH460 AH460 EH460
DH460 DH460 FH460 DH460 FH460
Steel grade AH500 EH500 AH500 EH500
DH500 FH500 DH500 FH500
AH550 EH550 AH550 EH550
DH550 FH550 DH550 FH550
AH620 EH620 AH620 EH620
DH620 FH620 DH620 FH620
Chemical AH690 EH690 AH690 EH690
Composition2) DH690 FH690 DH690 FH690
AH890 DH890 AH890 DH890
EH890 AH960 EH890
DH960
EH960
Carbon % max 0.20 0.18 0.16 0.14 0.18
Manganese % 1.0~1.70 1.0~1.70 1.70
Silicon % max 0.60 0.60 0.80
Phosphorus % max3) 0.030 0.025 0.025 0.020 0.025 0.020
Sulphur % max3) 0.025 0.020 0.015 0.010 0.015 0.010
Aluminiumtotal % min4) 0.02 0.02 0.018
Niobium % max5) 0.05 0.05 0.06
Vanadium % max5) 0.20 0.12 0.12
Titanium % max5) 0.05 0.05 0.05
Nickel % max6) 0.80 2.006) 2.006)
Copper % max 0.55 0.55 0.50
Chromium % max5) 0.30 0.50 1.50
Molybdenum % max5) 0.10 0.50 0.70
Nitrogen % max 0.025 0.025 0.015
Oxygen ppm max7) Not 50 Not 30
Not applicable applicable applicabl
e
Note 1 See section 4.5 for definition of delivery conditions

Note 2 The chemical composition is to be determined by ladle analysis and is to meet the approved
manufacturing specification at the time of approval.

Note 3 For sections the P and S content can be 0.005 % higher than the value specified in the table.

Note 4 The total aluminium to nitrogen ratio shall be a minimum of 2:1. When other nitrogen binding
elements are used, the minimum Al value and Al/N ratio do not apply.

Note 5 Total Nb+V+Ti ≤ 0.26 % and Mo+Cr ≤0.65%, not applicable for QT steels.

Note 6 Higher Ni content may be approved at the discretion of IRS.

Note 7 The requirement on maximum Oxygen content is only applicable to DH890; EH890; DH960
and EH960.

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Table 4.4.2 : Maximum Ceq, CET and Pcm values

Carbon Equivalent (%)

Ceq CET Pcm

Plates Sections Bars Tubulars all all

Steel grade &
delivery
condition t≤250
t≤50 50<t≤100 100<t≤250 t≤50 t≤65
or d≤250 all all
(mm) (mm) (mm) (mm) (mm)
(mm)

H420N/NR 0.46 0.48 0.52 0.47 0.53 0.47 N.A N.A

H420TM 0.43 0.45 0.47 0.44 N.A N.A N.A N.A
H420QT 0.45 0.47 0.49 N.A N.A 0.46 N.A N.A
H460N/NR 0.50 0.52 0.54 0.51 0.55 0.51 0.25 N.A
H460TM 0.45 0.47 0.48 0.46 N.A N.A 0.30 0.23
H460QT 0.47 0.48 0.50 N.A N.A 0.48 0.32 0.24
H500TM 0.46 0.48 0.50 N.A N.A N.A 0.32 0.24
H500QT 0.48 0.50 0.54 N.A N.A 0.50 0.34 0.25
H550TM 0.48 0.50 0.54 N.A N.A N.A 0.34 0.25
H550QT 0.56 0.60 0.64 N.A N.A 0.56 0.36 0.28
H620TM 0.50 0.52 N.A N.A N.A N.A 0.34 0.26
H620QT 0.56 0.60 0.64 N.A N.A 0.58 0.38 0.30
H690TM 0.56 N.A N.A N.A N.A N.A 0.36 0.30
H690QT 0.64 0.66 0.70 N.A N.A 0.68 0.40 0.33
H890TM 0.60 N.A N.A N.A N.A N.A 0.38 0.28
H890QT 0.68 0.75 N.A N.A N.A N.A 0.40 N.A
H960QT 0.75 N.A N.A N.A N.A N.A 0.40 N.A
Note:
N.A = Not applicable

4.5 Delivery Condition - Rolling Process and Note: Direct quenching after hot-rolling followed
Heat Treatment by tempering is considered equivalent to
conventional quenching and tempering.
4.5.1 Steel is to be delivered in accordance with
the processes approved by IRS. These 4.5.2 Rolling reduction ratio
processes include:
4.5.2.1 The rolling reduction ratio of slab, billet,
 Normalized (N)/Normalized rolled (NR) bloom or ingot is not to be less than 3:1 unless
agreed at the time of approval.
 Thermo-mechanical controlled rolled
(TM)/with Accelerated cooling 4.5.3 Thickness limits for approval
(TM+AcC)/with direct quenching
followed by tempering (TM+DQ), or 4.5.3.1 The maximum thickness of slab, billet or
bloom from the continuous casting process is to
 Quenched and Tempered condition be at the manufacturer’s discretion.
(QT)
4.5.3.2 Maximum thickness of plates, sections,
The definition of these delivery conditions are bars and tubulars over which a specific delivery
defined in previous sections. condition is applicable are shown in Table 4.5.3.

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Table 4.5.3 : Maximum thickness limits

Maximum thickness (mm)
Delivery condition
Plates Sections Bars Tubulars
N 2502) 50 250 65
NR 150 1)

TM 150 50 Not applicable Not applicable

QT 1502) 50 Not applicable 50

Note 1 The maximum thickness limits of sections, bars and tubulars produced by NR process
route are less than those manufactured by N route, and are to be at the discretion of IRS.

Note 2 Approval for N steels with thickness larger than 250 [mm] and QT steels with thickness
larger than 150 [mm] is subject to the special consideration of IRS.

4.6 Mechanical Properties use of a full thickness specimen, sub-sized flat

tensile specimens representing either the full
4.6.1 Test specimens and test procedures for thickness or half of the product thickness
mechanical properties are in accordance with retaining one rolled surface are to be used.
Chapter 2 and Section 3 of this chapter. Alternatively, machined round test specimens
may be used. The specimens are to be located
4.6.2 Tensile test at a position lying at a distance of t/4 from the
surface and additionally at t/2 for thickness
4.6.2.1 Test specimens are to be cut with their above 100 [mm] or as near as possible to these
longitudinal axes transverse to the final direction positions.
of rolling, except in the case of sections, bars,
tubulars and rolled flats with a finished width of 4.6.2.3 The results of the tests are to comply
600 [mm] or less, where the tensile specimens with the appropriate requirements of Table
may be taken in the longitudinal direction. 4.6.2.3. In the case of product forms other than
plates and wide flats where longitudinal tests are
4.6.2.2 Full thickness flat tensile specimens are agreed, the elongation values are to be 2
to be prepared. The specimens are to be percentage units above those transverse
prepared in such a manner as to maintain the requirements as listed in Table 4.6.2.3.
rolling scale at least at one side. When the
capacity of the test machine is exceeded by the

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Table 4.6.2.3 : Tensile properties at ambient temperature for all steel grades

Minimum yield Ultimate tensile Minimum Charpy V-notch

strength ReH1) strength Rm Percentage impact test
Mechanical (N/mm2) (N/mm2) elongation
properties After fracture
Nominal thickness Nominal thickness (%) Test Minimum
(mm)4) (mm)4) L0=5.65√S0 2) temp (Joules)
Steel grade
(°C)
& delivery
≥3 >50 >100 ≥3 >100
condition T L3) T L
≤50 ≤ 100 ≤250 ≤100 ≤250
H420N/NR A 0
H420TM D -20
420 390 365 520~680 470~650 19 21 28 42
H420QT E -40
F -60
H460N/NR A 0
H460TM D -20
H460QT E 460 430 390 540~720 500~710 17 19 -40 31 46
F -60
H500TM A 0
H500QT D -20
E 500 480 440 590~770 540~720 17 19 -40 33 50
F -60
H550TM A 0
H550QT D -20
E 550 530 490 640~820 590~770 16 18 -40 37 55
F -60
H620TM A 0
H620QT D -20
620 580 560 700~890 650~830 15 17 41 62
E -40
F -60
H690TM A 0
H690QT D -20
690 650 630 770~940 710~900 14 16 46 69
E -40
F -60
H890TM A Not Not 0
H890QT D 890 830 applic 940~1100 applicabl 11 13 -20 46 69
E able e -40
H960QT A Not Not Not 0
D 960 applic applic 980~1150 applicabl 10 12 -20 46 69
E able able e -40
Note 1 For tensile test either the upper yield stress (ReH) or where ReH cannot be determined, the 0.2
percent proof stress (Rp0.2) is to be determined and the material is considered to comply with the
requirement if either value meets or exceeds the specified minimum value of yield strength.

Note 2 For full thickness flat test specimens with a width of 25 [mm] and a gauge length of 200 [mm]
the elongation is to comply with the minimum values shown in Table 4.6.2.4.

Note 3 In the case that the tensile specimen is parallel to the final rolling direction, the test result shall
comply with the requirement of elongation for longitudinal (L) direction.

Note 4 For plates and sections for applications, such as racks in offshore platforms etc, where the
design requires that tensile properties are maintained through the thickness, a decrease in the
minimum specified tensile properties is not permitted with an increase in the thickness.

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Table 4.6.2.4 : Elongation minimum values for a width of 25 [mm] and a 200 [mm]
gauge length1)

Strength Thickness [mm]

Grade  10 > 10  15 > 15  20 > 20  25 > 25  40 > 40  50 > 50  70
H420 11 13 14 15 16 17 18
H460 11 12 13 14 15 16 17
H500 10 11 12 13 14 15 16
H550 10 11 12 13 14 15 16
H620 9 11 12 12 13 14 15
H690 92) 102) 112) 11 12 13 14

Note 1 The tabulated elongation minimum values are the requirements for testing specimen in
transverse direction. H890 and 960 specimens and specimens which are not included in this table is
to be proportional specimens with a gauge length of L0=5.65√S0.

Note 2 For H690 plates with thickness ≤ 20 [mm], round specimen in accordance with Chapter 2 may
be used instead of the flat tensile specimen. The minimum elongation for testing specimen in
transverse direction is 14%.

4.6.3 Impact test 4.6.4.2 Impact test

4.6.3.1 The Charpy V-notch impact test a) For steels plates in N/NR or TM
specimens for plates and wide flats over 600 condition test sample is to be taken from
[mm] in width are to be taken with their axes each piece.
transverse to the final rolling direction and the
results should comply with the appropriate b) For steels in QT condition test sample is
requirements for transverse direction of Table to be taken from each individually heat
4.6.2.3. For other product forms, the impact treated part thereof.
tests are to be in the longitudinal direction, the
results of the tests are to comply with the c) For sections, bars and tubulars, test
appropriate requirements for longitudinal sample is to be taken from each batch
direction of Table 4.6.2.3. of 25 tonnes or fraction thereof.

4.6.3.2 Sub-surface test specimens will be taken Note 1: If the mass of the finished material is
in such a way that one side is not further away greater than 25 tonnes, one set of tests from
than 2 [mm] from a rolled surface, however, for each 25 tonnes and/or fraction thereof is
material with a thickness in excess of 50 [mm], required. (e.g. for consignment of 60 tonnes
impact tests are to be taken at the quarter would require 3 plates to be tested).
thickness (t/4) location and mid-thickness (t/2).
Note 2: For continuous heat treated product
4.6.3.3 Impact test for a nominal thickness less special consideration may be given to the
than 6 [mm] are normally not required. number and location of test specimens required
by the manufacturer to be agreed by IRS.
4.6.4 Test frequency
4.6.5 Traceability
4.6.4.1 Tensile test sample is to be randomly
selected from each batch, as defined in section 4.6.5.1 Traceability of test material, specimen
3, that is to be less than or equal to 25 tonnes, sampling and test procedures including test
and to be from the same cast, in the same equipment with respect to mechanical properties
delivery condition and of the same thickness. testing, is to be in accordance with section 3.

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4.6.6 Re-test procedures 4.9 Internal Soundness

4.6.6.1 Re-test procedures for tensile tests and 4.9.1 Verification of internal soundness is the
Charpy impact tests are to be in accordance responsibility of the manufacturer. The
with Chapter 2. acceptance by the IRS’s Surveyor shall not
absolve the manufacturer of this responsibility.
4.6.7 Through thickness tensile test
4.9.2 Ultrasonic examination
4.6.7.1 For steels designated with improved
through thickness properties, through thickness 4.9.2.1 If required by the IRS, ultrasonic
tensile tests are to be performed in accordance examination should be carried out in accordance
with Section 8. with Section 2 for the requirement of internal
soundness, and is to be performed in
4.6.7.2 Subject to the discretion of IRS, through accordance with an approved standard.
thickness tensile strength may be required to be
not less than 80% of the specified minimum 4.10 Stress relieving heat treatment and
tensile strength. other heat treatments

4.7 Tolerances 4.10.1 Steels approved by the procedures given

in Classification Note “Manufacturing Approval
4.7.1 Unless otherwise agreed or specially Scheme of High Strength Steels for Welded
required, the thickness tolerances in Sec 1, 1.4 Structures” with respect to Heat Treatment are
are applicable. suitable for stress relieving heat treatment such
as post-weld heat treatment and stress relieving
4.8 Surface Quality heat treatment after cold forming for the purpose
of reducing the risk of brittle fracture, increasing
4.8.1 All materials are to be free from cracks, the fatigue lifetime and dimensional stability for
injurious surface flaws, injurious laminations and machining.
similar defects.
Note: Products can be susceptible to
4.8.2 The surface quality inspection method is to deterioration in mechanical strength and
be in accordance with recognised national or toughness if they are subjected to incorrect
international standards agreed between post-weld heat treatment procedures or other
purchaser and manufacturer. processes involving heating such as flame
straightening, rerolling, etc. where the heating
a) Welding repair procedures and the temperature and the holding time exceed the
method for reporting repairs are to be limits given by the manufacturer.
approved by the IRS.
4.11 Facilities for Inspection
b) Where repair by grinding is carried
out then the remaining plate thickness 4.11.1 Testing is to be carried out under the
below the ground area must be within witness of the Surveyor, or an authorised
the allowable under thickness tolerance. deputy, in order to verify whether the test results
meet the specified requirements.
4.8.3 Surface finish requirement are to be in
accordance with the relevant requirements in 4.11.2 The manufacturer is to afford the
Section 3. Surveyor all necessary facilities and access to
all relevant parts of the steel works to enable
4.8.4 Surface inspection is the responsibility of him to verify the approved process is adhered
the manufacturer. The acceptance by IRS’s to, for the selection of test materials, and the
Surveyor of material later found to be defective witnessing of tests, as required by this Section.
shall not absolve the manufacturer of this Also for verifying the accuracy of the testing,
responsibility. calibration of inspection equipment and
traceability of materials.

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4.12 Identification of Materials material, the following particulars are to be
included:
4.12.1 The manufacturer is to adopt a system
for the identification of ingots, slabs, billet or a) Purchaser's order number
bloom and finished products, which will enable
the material to be traced to its original cast. The b) Identification of the cast and piece
Surveyor is to be given full facilities for so
tracing the material when required. c) Manufacturer’s identification

4.13 Branding d) Identification of the grade of steel

4.13.1 Each finished piece is to be clearly e) Chemical analysis, Ceq, CET or Pcm value
marked by the manufacturer with the following
particulars: f) Delivery condition with heat treatment
temperatures
a) IRS’s brand mark
g) Mechanical properties test results, including
b) Unified identification mark for the grade of traceable test identification
steel (e.g. EH620)
h) Surface quality and inspection results
c) Name or initials to identify the steelworks
i) UT result, where applicable
d) Cast number/Heat number, plate number or
equivalent identification mark 4.14.2 Before the test certificates are signed by
the Surveyor, the steelmaker is required to
e) Delivery condition (N/NR, provide a written declaration stating that the
TM/TM+AcC/TM+DQ or Q&T) material has been made by an approved
process, and that it has been subjected to and
The entire markings are to be encircled with has withstood satisfactorily the required tests in
paint or otherwise marked so as to be easily the presence of the Surveyor, or an authorised
recognised. Steels which have been specially deputy. The following form of declaration will be
approved by IRS and which differ from these accepted if stamped or printed on each test
requirements (see 4.1.6) are to have the letter certificate with the name of the steelworks and
“S” after the identification mark (e.g. EH620S) signed by an authorised representative of the
manufacturer:
4.14 Documentation of Inspection Tests “We hereby certify that the material has been
made by an approved process and has been
4.14.1 The Surveyor is to be supplied with two satisfactorily tested in accordance with the
copies, of the test certificates or shipping Rules of IRS”.
statements for all accepted materials. In addition
to the description, dimensions, etc., of the

Section 5

Steel for Low Temperature Service

5.1 General where the use of steels with guaranteed impact

properties at low temperature is required.
5.1.1 This section gives specific requirements
for carbon-manganese and nickel alloy steels 5.1.3 Provision is made for plates and sections
with toughness properties at low temperatures up to 40 [mm] thick.
and intended for use in the construction of cargo
tanks and process pressure vessels for liquefied 5.1.4 Steel differing in chemical composition,
gases. condition of supply or mechanical properties
may be accepted, subject to special agreement
5.1.2 The requirements of this section are also by IRS.
applicable for other types of pressure vessels

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5.2 Deoxidation and chemical composition Table 3.2.1). However, these grades are to be
designated as L T -AH, L T -DH, L T -EH and L
5.2.1 All steels are to be in the fully killed and T -FH respectively for the uses defined in 5.1.1.
fine grain refined condition.
5.2.3 The chemical compositions of nickel alloy
5.2.2 The chemical composition of carbon- steels are to comply with the appropriate
manganese steels are to comply with the requirements of Table 5.2.1.
appropriate requirements of grades AH, DH, EH
and FH strength levels 32, 36 and 40 (See

Table 5.2.1 : Chemical composition of nickel alloy steels

Elements 1.5 Ni 3.5 Ni 5 Ni 9 Ni

C max. 0.18 0.15 0.12 0.10
Si 0.10 - 0.35 0.10 - 0.35 0.10 - 0.35 0.10 - 0.35
Mn 0.30 - 1.50 0.30 - 0.90 0.30 - 0.90 0.30 - 0.90
Ni 1.30 - 1.70 3.20 - 3.80 4.70 - 5.30 8.50 - 10.0
P max. 0.025 0.025 0.025 0.025
S max. 0.020 0.020 0.020 0.020
Al min. (acid soluble)1) 0.015 0.015 0.015 0.015
Residual elements
Cr max. 0.25 0.25 0.25 0.25
Cu max. 0.35 0.35 0.35 0.35
Mo max. 0.08 0.08 0.08 0.08
Total of residual
0.60 0.60 0.60 0.60
elements max.
1) The total aluminium content may be determined by other methods instead of the acid soluble
method. In such cases the total aluminium content is to be not less than 0.020 percent.

5.3 Heat treatment

5.3.1 All materials are to be supplied in a

condition complying with Table 5.3.1.

Table 5.3.1 : Conditions of supply

Grade Plates Sections and Bars

LT-AH N, TMCP Any
LT-DH N, TMCP Any
LT-EH N2, TMCP, QT N, TMCP
LT-EH N2, TMCP, QT N, TMCP
1.5 Ni N2, QT, normalized and tempered
3.5 Ni N2, QT, normalized and tempered
5 Ni N2, QT, normalized and tempered
9 Ni QT, Double normalized and tempered
1 N = Normalized
TMCP = Thermo-mechanically controlled process
QT = Quenched and tempered
2 The term "Normalized" does not include normalized rolling.

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5.4 Mechanical tests test specimen required. For plates, these are to
be cut with their principal axis perpendicular to
5.4.1 Test pieces for tensile testing of plates are the final direction of rolling and for sections.
to be cut with their principal axes transverse to these are to be taken longitudinally.
the final direction of rolling.
5.4.5 The results of all tensile tests are to
5.4.2 For each batch of plate presented, one comply with appropriate requirements given in
tensile test is to be made from one end of each Table 5.4.1. The ratio between the yield stress
piece unless the mass and length of the piece and the tensile strength is not to exceed 0.9 for
exceeds 5 tonnes and 15 m in which case test normalized and TMCP steels and 0.94 for Q & T
pieces are to be taken from both ends of each steels.
piece.
5.4.6 The average energy value from each set
5.4.3 Sections and bars are to be presented for of three impact tests are to comply with
acceptance test in batches containing not more appropriate requirements given in Table 5.4.1.
than 50 lengths, as supplied. The material in
each batch is to be of the same section size, 5.4.7 When standard subsidiary impact
from the same cast and in the same condition of specimens are necessary (See Sec. 2).
supply. One tensile test specimen is to be taken
from material representative of each batch, 5.4.8 When steel with improved through
except that additional tests are to be taken when thickness properties is required or specified in
the mass of a batch exceeds 10 tonnes. the order, the materials are to be tested as
detailed in Sec. 8.
5.4.4 One set of three Charpy V-notch impact
test specimens are to be taken for each tensile

Table 5.4.1 : Mechanical properties for acceptance purposes

Charpy V-notch impact

Yield test
Tensile Elongation
stress
Grade of Steel strength on 5.65So Impact
[N/mm2] Test
[N/mm2] % min. Energy
min. temp.C
min.
LT-AH 32 315 440 - 590 22 0
36 355 490 - 620 21
40 390 510 - 650 20
LT-DH 32 315 440 - 590 22 -20
36 355 490 - 620 21 Plates
transverse
40 390 510 - 650 20
tests
LT-EH 32 315 440 - 590 22 -40 Average
36 355 490 - 620 21 energy 27 J
Sections
40 390 510 - 650 20 and bars
LT-FH 32 315 440 - 590 22 -60 longitudinal
36 355 490 - 620 21 tests
Average
40 390 510 - 650 20 energy 41 J
1.5 Ni 275 490 - 640 22 -80
3.5 Ni 285 450 - 610 21 -95
5 Ni 390 540 - 740 21 -110
9 Ni 490 640 - 790 18 -196

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Notes:

1 These requirements are applicable to products not exceeding 40 [mm] in thickness. The
requirements for thicker products are subject to agreement.
2 The minimum design temperatures at which plates of different thicknesses in the above grades
may be used are given in Pt.3, Ch.2, Table 2.4.1 and Pt.5, Ch.4, Table 6.1.2 and Table 6.1.3.
Consideration will be given to the use of thicknesses greater than those in the table or to the use
of temperatures below - 165C

Section 6

Steels for Boilers and Pressure Vessels

6.1 General [N/mm2] may be accepted provided that details

of proposed specifications are submitted for
6.1.1 The following requirements are for carbon, approval.
carbon-manganese and alloy steels intended for
use in the construction of boilers and pressure 6.1.4 Where it is proposed to use alloy steels
vessels. In addition to specifying mechanical other than those specified herein, details of the
properties at ambient temperature for the specifications are to be submitted for approval.
purpose of acceptance testing, these In such cases the specified minimum tensile
requirements also give details of appropriate strength is not to exceed 600 [N/mm2].
mechanical properties at elevated temperatures
which may be used for design purposes. 6.1.5 Materials intended for use in the
construction of the cargo tanks and process
6.1.2 Where it is proposed to use a carbon or pressure vessels, storage tanks for liquefied
carbon-manganese steel with a specified gases and for other low temperature
minimum tensile strength intermediate to the applications are to comply with the requirements
following specified properties, corresponding of Sec. 5.
minimum values for yield and elongation and
mechanical properties at elevated temperatures 6.2 Deoxidation and chemical composition
may be obtained by interpolation.
6.2.1 The method of deoxidation and the
6.1.3 Carbon and carbon-manganese steels chemical analysis of ladle samples is to comply
with a specified minimum tensile strength of with the requirements of Table 6.2.1.
greater than 490 [N/mm2] but not exceeding 520

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Table 6.2.1 : Deoxidation and chemical composition

Grade of
Chemical composition per cent
steel
Deoxidation
C and C-Mn P Residual
C max. Si Mn S max. Al
steel max. elements
360 AR 0.18 0.50 max. 0.40-1.30 0.040 0.04 -
Any method
410 AR except 0.21 0.50 max. 0.40-1.30 0.040 0.040 -
460 AR rimmed steel 0.23 0.50 max. 0.80-1.50 0.040 0.040 - Cr 0.25
360 0.17 0.35 max. 0.40-1.20 0.035 0.035 max.
Any method - Cu 0.30
410 except 0.20 0.35 max. 0.50-1.30 0.035 0.035 max.
rimmed steel -
460 0.201 0.40 max. 0.80-1.40 0.035 0.035 Mo 0.10
- max.
490 Killed 0.201 0.10-0.50 0.90-1.60 0.035 0.035 Ni 0.30
360 FG 0.17 0.35 max. 0.40-1.20 0.035 0.035 See note 2 max.
Total 0.70
410 FG 0.20 0.35 max. 0.50-1.30 0.035 0.035 See note 2 max.
Killed fine
460 FG grained 0.201 0.40 max. 0.80-1.50 0.035 0.035 See note 2
490 FG 0.201 0.10-0.50 0.90-1.60 0.035 0.035 See note 2
Deoxi- P S Residual
Alloy steels C Si Mn Al Cr Mo
dation max. max. elements
1 Cr 1/2 Mo 0.10- 0.15- See 0.70- 0.40-
0.4-0.8 0.035 0.035 Cu 0.30
470 0.18 0.35 note 3 1.30 0.60
Killed max. Ni
2 1/4 Cr 1 0.08- 0.15- See 2.00- 0.90-
0.4-0.8 0.035 0.035 0.30 max.
Mo 480 0.18 0.50 note 3 2.50 1.10
Notes:
1 For thickness greater than 30 [mm], carbon 0.22 percent max.
2 Aluminium (acid soluble) 0.015 per cent min, or Aluminium (total) 0.018 percent min. Niobium, Vanadium or
other suitable grain refining elements may be used either in place of or in addition to aluminium.
3 Aluminium (acid soluble or total) 0.020 percent max.

6.3 Heat treatment, condition of supply

However, when agreed, material intended for
6.3.1 All materials are to be supplied in a hot forming may be supplied in the as rolled
condition complying with the requirements of condition.
Table 6.3.1.

Table 6.3.1 : Heat treatment

Grade of steel Condition of supply
Carbon and carbon- manganese 360 AR to 460 As rolled, maximum thickness or diameter is 40 [mm]
AR
Carbon and carbon- manganese 360 to 490 Normalized or controlled rolled
Carbon and carbon- manganese 360 FG to 490 Normalized or controlled rolled
FG
1Cr 1/2 Mo 470 Normalized and tempered
2 1/4 Cr 1 Mo 480 Normalized and tempered

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6.4 Mechanical tests 6.4.4 Where plates are required for hot forming
and it has been agreed that the heat treatment
6.4.1 For plates a tensile test specimen is to be will be carried out by the fabricator, the tests at
taken from one end of each piece when the the steel works are to be made on material
weight does not exceed 5 tonnes and the length which has been cut from the plates and given a
does not exceed 15 [m]. When either of these normalizing or normalizing and tempering heat
limits is exceeded, tensile test specimens are to treatment in a manner simulating the treatment
be taken from both ends of each piece. A piece which will be applied to the plates.
is to be regarded as the rolled product from a
single slab or a single ingot, if this is rolled 6.4.5 If required by the Surveyors or by the
directly into plates. fabricator test material may be given a simulated
stress relieving heat treatment prior to the
6.4.2 For strips, tensile test specimens are to be preparation of the test specimens. This has to
taken from both ends of each coil. be stated on the order together with agreed
details of the simulated heat treatment and the
6.4.3 Sections and bars are to be presented for mechanical properties which can be accepted.
acceptance tests in batches containing not more
than 50 lengths, as supplied. The material in 6.4.6 The results of the tensile tests are to
each batch is to be of the same section size, comply with the appropriate requirements given
from the same cast and in the same condition of in Table 6.4.1, Table 6.4.2 and Table 6.4.3.
supply. One tensile test specimen is to be taken
from material representative of each batch,
except that additional tests are to be taken when
the weight of a batch exceeds 10 tonnes.

Table 6.4.1 : Mechanical properties for acceptance purposes :

carbon and carbon-manganese steels - as rolled

Grade of steel Thick-ness [mm] Yield stress Tensile strength Elonga-tion on

[N/mm2] min. [N/mm2] 5.65So % min.
360 AR  40 190 360-480 24
410 AR  40 215 410-530 22
460 AR  40 240 460-580 21

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Table 6.4.2 : Mechanical properties for acceptance purposes : carbon and carbon-manganese
steels-normalized or controlled rolled

Thickness [mm] Yield stress Tensile strength Elongation on

Grade of steel
(see Note) [N/mm2] min. [N/mm2] 5.65So % min.
> 3  16 205 26
360 > 16  40 195 360 - 480 26
> 40  63 185 25
> 3  16 235 24
410 > 16  40 225 410 - 530 24
> 40  63 215 23
> 3  16 285 22
460 > 16  40 255 460 - 580 22
> 40  63 245 21
> 3  16 305 21
490 > 16  40 275 490 - 610 21
> 40  63 265 20
> 3  16 235 26
360 FG > 16  40 215 360 - 480 26
> 40  63 195 25
> 3  16 265 24
410 FG > 16  40 245 410 - 530 24
> 40  63 235 23
> 3  16 295 22
460 FG > 16  40 285 460 - 580 22
> 40  63 275 21
> 3  16 315 21
490 FG > 16  40 315 490 - 610 21
> 40  63 305 21

Note:

For thicknesses greater than 63 [mm], the minimum values for yield stress may be reduced by 1 per
cent for each 5 [mm] increment in thickness over 63 [mm]. The minimum elongation values may also
be reduced one unit, e.g. 20 percent reduced to 19 percent for all thicknesses over 63 [mm]. For
thicknesses over 100 [mm], the above values are to be agreed.

Table 6.4.3 : Mechanical properties for acceptance purposes :

alloy steels-normalized and tempered

Thickness [mm] Yield stress Tensile strength Elongation on

Grade of steel
(see Note) [N/mm2] min. [N/mm2] 5.65So % min.
> 3  16 305 20
1 CR 1/2 Mo 470 > 16  40 305 470 - 620 20
> 40  63 305 19
> 3  16 275 18
2 1/4 Cr 1 Mo 480 > 16  40 265 480 - 630 18
> 40  63 265 17

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Table 6.4.3 (Contd.)

Note:

For thicknesses greater than 63 [mm], the minimum values for yield stress may be reduced by 1 per
cent for each 5 [mm] increment in thickness over 63 [mm]. The minimum elongation values may also
be reduced one unit, e.g. 20 percent reduced to 19 percent for all thicknesses over 63 [mm]. For
thicknesses over 100 [mm], the above values are to be agreed.

6.5 Mechanical properties for design Table 6.5.3 Alloy steels. Normalized and
purposes at elevated temperatures tempered.

6.5.1 Nominal values for the minimum lower 6.5.2 These values are intended for design
yield or 0.2 per cent proof stress at purposes only and verification is not required
temperatures of 50°C and higher are given in except for materials complying with National or
the following tables : proprietary specifications where the elevated
temperature properties used for design
Table 6.5.1 Carbon and carbon manganese purposes are higher than those given in Table
steels - As rolled (applicable 6.5.1 to Table 6.5.3. The extent of testing in
only when the design such cases would have to be specially agreed
temperature does not exceed by IRS.
350°C).
6.5.3 Values for the estimated average stress to
Table 6.5.2 Carbon and carbon-manganese
rupture in 100,000 hours are given in Table
steels normalized or controlled
6.5.4 and may be used for design purposes.
rolled.

Table 6.5.1 : Mechanical properties for design purposes - Carbon and carbon -
manganese steels - as rolled

Grade Thickness Design temperatureC (See Note)

of steel [mm] 50 10 150 200 250 300 350
Nominal minimum lower yield or 0.2 percent proof stress [N/mm2]
360 AR 154 153 152 145 128 108 102
410 AR  40 186 183 181 174 155 134 127
460 AR 218 213 210 203 182 161 153
Note : Maximum permissible design temperature is 350C

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Table 6.5.2 : Mechanical properties for design purposes - carbon and carbon - manganese
steels - normalized or controlled rolled

Grade Thickness Design temperature C

of steel [mm] (see 50 100 150 200 250 300 350 400 450
Note)
Nominal minimum lower yield or 0.2 percent proof stress [N/mm2]
183 175 172 168 150 128 117 115 113
> 3  16
360 > 16  40 173 171 169 162 144 124 117 115 113
> 40  63 166 162 158 152 141 124 117 115 113
> 3  16 220 211 208 201 180 150 142 138 136
410 > 16  40 204 201 198 191 171 150 142 138 136
> 40  63 196 192 188 181 168 150 142 138 136
> 3  16 260 248 243 235 210 176 168 162 158
460 > 16  40 235 230 227 220 198 176 168 162 158
> 40  63 227 222 218 210 194 176 168 162 158
> 3  16 280 270 264 255 228 192 183 177 172
490 > 16  40 255 248 245 237 214 192 183 177 172
> 40  63 245 240 236 227 210 192 183 177 172
> 3  16 214 204 185 165 145 127 116 110 106
360 FG > 16  40 200 196 183 164 145 127 116 110 106
> 40  63 183 179 172 159 145 127 116 110 106
> 3  16 248 235 216 194 171 152 141 134 130
410 FG > 16  40 235 228 213 192 171 152 141 134 130
> 40  63 222 215 204 188 171 152 141 134 130
> 3  16 276 262 247 223 198 177 167 158 153
460 FG > 16  40 217 260 242 220 198 177 167 158 153
> 40  63 262 251 236 217 198 177 167 158 153
> 3  16 297 284 265 240 213 192 182 173 168
490 FG > 16  40 293 279 260 237 213 192 182 173 168
> 40  63 286 272 256 234 213 192 182 173 168

Note : For thicknesses greater than 63 [mm], the values for lower yield or 0.2 percent stress are to be reduced
by 1 percent for each 5 [mm] increment in thickness upto 100 [mm]. For thicknesses over 100 [mm], the
values are to be agreed and verified by test.

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Table 6.5.3 : Mechanical properties for design purposes : alloy steels-normalized tempered

Grade of steel Thickness Design temperature C

[mm] (see 50 100 200 300 350 400 450 500 550 600
Note) Nominal minimum lower yield or 0.2 percent proof stress [N/mm2]
1 Cr 1/2 Mo 470 3  63 284 270 248 216 203 199 194 188 181 174
2 1/4 Cr 1 Mo 480 3  63 255 249 233 219 212 207 194 180 160 137
Note : For thicknesses greater than 63 [mm], the values for lower yield or 0.2 percent stress are to be reduced
by 1 percent for each 5 [mm] increment in thickness upto 100 [mm]. For thicknesses over 100 [mm], the values
are to be agreed and verified by test.

Table 6.5.4 : Mechanical properties for design purposes : estimated average values for stress
to rupture in 100,000 hours [N/mm2]

Grades of steel
Carbon and carbon-manganese Alloy Steels
Temp. C 360 FG 360 490
410 FG 410 490 FG 1 Cr 1/2 Mo 470 2 1/4 Cr 1 Mo 480
460 FG 460 510 FG
380 171 219 227 - -
390 155 196 203 - -
400 141 173 179 - -
410 127 151 157 - -
420 114 129 136 - -
430 102 109 117 - -
440 90 92 100 - -
450 78 78 85 - 221
460 67 67 73 - 204
470 57 57 63 - 186
480 47 48 55 210 170
490 36 - 47 177 153
500 - - - 146 137
510 - - - 121 122
520 - - - 99 107
530 - - - 81 93
540 - - - 67 79
550 - - - 54 69
560 - - - 43 59
570 - - - 35 51
580 - - - - 44

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Section 7

Steels for Machinery Structures

7.1 General
b) Any grade of carbon or carbon-manganese
7.1.1 Steel plates, strips, sections or bars steel as detailed in Sec. 6 except that for
intended for use in the construction of welded this application batch testing is acceptable
machinery structures are to comply with one of and the same is to be carried out in
the following alternatives: accordance with the requirements of Sec. 2.

a) Any grade of normal strength structural steel

or high strength structural steel as detailed
in Sec. 2 and 3.

Section 8

Plates with Specified minimum through Thickness Properties

(‘Z’ quality)

8.1 General 8.2 Manufacture

8.1.1 Following requirements are for special 8.2.1 All plates are to be manufactured at works
quality plate material with improved ductility in which have been approved by IRS for this
the through thickness or "Z direction. quality of material. Also refer Chapter 1, Section
1, Cl. 1.3.2.
8.1.2 The use of this material known as ‘Z’
quality steel, is recommended when plate 8.2.2 The sulphur content is not to exceed 0.008
material, intended for welded construction, will per cent, as determined by ladle analysis. It is
be subject to significant strain in a direction recommended that the steel should be efficiently
perpendicular to the rolled surfaces. These vacuum de-gassed.
strains are usually associated with thermal
contraction and restraint during welding, 8.3 Test material
particularly for full penetration "T"- butt welds but
may also be associated with loads applied in 8.3.1 Unless otherwise agreed, through
service or during construction. Where these thickness tensile tests are only required for plate
strains are of sufficient magnitude, lamellar materials where the thickness exceeds 15 [mm].
tearing may occur. Two ‘Z’ quality steels are A test sample large enough to provide six test
specified; Z25 for normal ship applications and specimens are to be cut from the centre of one
‘Z35’ for more severe applications. end of each rolled piece representing the batch.
(See Fig.8.3.1). Where appropriate the end
Through thickness properties are characterized selected should be representative of the top end
by specified values for reduction of area in a of an ingot or the start of a concast strand.
through thickness tensile test. Generally three through thickness tensile test
specimens are to be prepared while the rest of
8.1.3 This special quality material is to comply the sample remains for possible retests.
with the requirements of Sec. 2, 3, 4, 5, 6 and 7
as appropriate and the following additional 8.3.2 The batch size is to be determined
requirements. depending on the product and sulphur content
as given in Table 8.3.2.

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Fig.8.3.1 : Plate and wide flat sampling position

Table 8.3.2 : Batch size dependent on product and sulphur content

Product S > 0.005% S  0.005%

Plates Each piece (parent plate) Maximum 50t of products of the
same cast, thickness and heat
treatment
Wide flats of nominal thickness Maximum 10t of products of the Maximum 50t of products of the
 25 mm same cast, thickness and heat same cast, thickness and heat
treatment treatment
Wide flats of nominal thickness Maximum 20t of products of the Maximum 50t of products of the
> 25 mm same cast, thickness and heat same cast, thickness and heat
treatment treatment

8.4 Dimensions of through thickness tensile

test specimens Alternatively, round test specimens, including
those with welded extensions, may be prepared
8.4.1 At the option of the steel maker test in accordance with a recognized standard.
specimens (Fig.8.4.1a) or test specimens with
welded extensions (Fig.8.4.1b) may be used. 8.4.2 The tolerances on specimen dimensions
For both types of test specimens, the diameter are to be in accordance with ISO 6892-98 or
of the parallel portion is not to be less than 6 other recognised standards as appropriate.
[mm] when plate thickness is less than or equal
to 25 [mm] and 10 [mm] when the plate
thickness is greater than 25 [mm].

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8.5 Mechanical tests 8.5.2 A value less than minimum individual

value will require rejection of the piece.
8.5.1 The acceptable minimum average value However, in case of batch testing each
for the reduction of area of the three tensile test remaining piece in the batch may be individually
specimens taken in the through thickness tested.
direction are given in Table 8.5.1. Only one
individual value may be below the minimum 8.5.3 Depending on the test results, retest may
average, but not less than the minimum be permitted in the cases shown in Fig.8.5.3. In
individual value for the appropriate grade. these instances, three more tensile tests are to
be taken from the remaining test sample. The
Table 8.5.1 : Reduction of area acceptance average of all 6 tensile tests is to be greater
values than the required minimum average with not
Grade Z25 Z35 more than two results below the minimum
average.
Minimum average 25% 35%
Minimum individual 15% 25% In case of failure after retest, either the batch
represented by the piece is rejected or each
piece within batch may be retested.

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Fig.8.5.3 : Diagram showing acceptance / rejection and retest criteria

8.6 Non-destructive examination testing is to be carried out in accordance with

either EN 10160-1989 Level S2/E3 or ASTM
8.6.1 All special ‘Z’ quality plates are to be A578 Level C.
ultrasonically tested in the final supply condition,
with a probe of frequency 4 MHz. The ultrasonic

Section 9

Austenitic and Duplex Stainless Steels

9.1 Scope 9.1.4 Duplex stainless steels are suitable for

applications where the lowest design
9.1.1 This section gives the requirements for temperature is above 0C. Any requirement to
rolled products in austenitic and duplex use duplex stainless steels below 0C will be
(austenite plus ferrite) stainless steels intended subject to special consideration.
for use in the construction of cargo tanks,
storage tanks and process pressure vessels for 9.1.5 Duplex stainless steels are also suitable
chemicals and liquefied gases. for service at temperatures upto 300C and for
such applications the proposed specification
9.1.2 Austenitic stainless steels are suitable for should include, in addition to the requirements of
applications where the lowest design 9.1.6, a minimum value for 0.2 per cent proof
temperature is not lower than –165C. stress at the design temperature.

9.1.3 Austenitic stainless steels are also suitable 9.1.6 A specification giving details of the
for service at elevated temperatures and for chemical composition, heat treatment and
such applications the proposed specification mechanical properties, including for the
should contain, in addition to the requirements austenitic grades, both the 0.2 and 1.0 percent
of 9.1.6, minimum values for 0.2 and 1.0 per proof stresses, is to be submitted for
cent proof stresses at the design temperature. consideration and approval.

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9.2 Chemical composition 9.3 Heat treatment

9.2.1 The chemical composition of ladle 9.3.1 All materials are to be supplied in the
samples is to comply with the requirements solution treated condition.
given in Table 9.2.1.

Table 9.2.1 : Chemical composition

Type and Chemical composition % (see Note)

grade of steel C Si Mn P max S Cr Ni Mo N Other
max max max max

Austenitic
304L 0.03 } } } } 17.0-20.0 8.0-13.0 - 0.10 -
304LN “ } } } } 17.0-20.0 3.0-12.0 - 0.10-0.22 -
316L “ } } } } 16.0-18.5 10.0-15.0 2.0-3.0 0.10 -
316LN “ 1.0 2.0 0.045 0.03 16.0-18.5 10.0-14.5 2.0-3.0 0.10-0.22 -
317L “ } } } } 18.0-20.0 11.0-15.0 3.0-4.0 0.10 -
317LN “ } } } } 18.0-20.0 12.5-15.0 3.0-4.0 0.10-0.22 -
321 0.06 } } } } 17.0-19.0 9.0-12.0 - 0.10 5xCTi0.7
347 0.06 } } } } 17.0-19.0 9.0-13.0 - 0.10 10xCNb1.0

Duplex
UNS S31803 0.03 1.0 2.0 0.03 0.02 21.0-23.0 4.5-6.5 2.5-3.5 0.08-0.20 -
UNS S32750 0.03 0.80 1.2 0.035 0.02 24.0-26.0 6.0-8.0 3.0-5.0 0.24-0.32 Cu 0.50 max.

9.4 Mechanical tests 9.4.3 Where standard subsidiary Charpy V-

notch test specimens are necessary, see
9.4.1 Tensile test specimens are to be taken in Chapter 2, Sec.3.1.2.
accordance with the appropriate requirements of
5.4 and 6.4.1. 9.4.4 The results of all tensile tests are to
comply with the requirements of Table 9.4.1 or
9.4.2 For the duplex grades, one set of three the approved specification.
Charpy V-notch impact test specimens
machined in the longitudinal direction from each 9.5 Through thickness tests
tensile test piece is to be tested at –20C. The
average energy value of the three specimens is 9.5.1 Where material will be strained in a
to be not less than 41 Joules. through thickness direction during welding or in
service, through thickness tests are required on
For austenitic grades of steel, impact tests are plates over 10 [mm] thick in all the grades of
only required for design temp. below –105C. In steels listed in Table 9.2.1, apart from Grades
such cases, impact tests carried out at a 304L, 304LN, 321 and 347.
temperature of –196C on a set of three charpy
V-notch specimens are to comply with the 9.5.2 Testing is to conform with the
following: requirements of Section 8, with the exception
given in 9.5.3.
a) Plates : Transverse test pieces;
minimum average energy value 27 9.5.3 When the reduction in area is less than 35
Joules. per cent, metallographic or other evidence is
b) Strips, sections and bars : Longitudinal required to show that no significant amount of
test pieces, minimum average energy any detrimental phase, such as sigma, is
value 41 Joules. present.

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Table 9.4.1 : Mechanical properties for acceptance purposes

Type and grade 0.2% proof stress 1% proof stress Tensile strength Elongation on
of steel [N/mm2] [N/mm2] [N.mm2] 5.65 So
minimum minimum minimum % minimum
Austenitic
304L 170 210 485 40
304LN 205 245 515 40
316L 170 210 485 40
316LN 205 245 515 40
317L 205 245 515 40
317LN 240 280 550 40
321 205 245 515 40
347 205 245 515 40
Duplex
UNS S 31803 450 - 620 25
UNS S 32750 550 - 795 15

9.6 Intergranular corrosion tests 9.8.2 The carbon or carbon-manganese steel

base plates are to comply with the requirements
9.6.1 For certain specific applications such as of Section 6 and the austenitic or duplex
storage tanks for chemicals, it may be cladding material generally with the
necessary to demonstrate that the material used requirements of this section.
is not susceptible to intergranular corrosion
resulting from grain boundary precipitation of 9.8.3 The process of manufacture is to be
chromium-rich carbides. specially approved and may be either by roll
cladding or by explosive bonding.
9.6.2 When required, one test of this type is to
be carried out for each tensile test. The testing 9.8.4 Where the use of clad materials is
is to be carried out in accordance with ASTM proposed, the material specification is to be
A262, practice E, copper-copper sulphate- submitted for consideration, together with details
sulphuric acid or another recognized standard. of the extent and the acceptance standards for
The bent specimen is to be free from cracks non-destructive examination.
indicating the presence of intergranular attack.
The material for the test is to be taken adjacent 9.9 Identification of materials
to that for the tensile test.
9.9.1 The particulars detailed in 1.12 are to be
9.7 Dimensional tolerances marked on all materials which have been
accepted.
9.7.1 The minimum tolerance on thickness is to
be as given in Table 1.4.1. 9.10 Certification of materials

9.8 Clad plates 9.10.1 Each test certified or shipping statement

is to give the information detailed in 1.13,
9.8.1 Carbon or carbon-manganese steel plates, together with general details of heat treatment
clad on one or both surfaces with a suitable and where applicable, the results obtained from
grade of austenitic or duplex stainless steel, intercrystalline corrosion tests. The chemical
may be used for the construction of cargo or composition is to include the content of all the
storage tanks for chemicals. elements detailed in Table 9.2.1.

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Section 10

Brittle Crack Arrest Steels

10.1 General
10.1.3 The brittle crack arrest properties
10.1.1 Brittle crack arrest steels are defined as specified in Table 10.1.3 are to be evaluated
steel plate with the specified brittle crack arrest and approved by IRS. Test specimens are to be
properties measured by either the brittle crack taken from each piece (means “the rolled
arrest toughness Kca or Crack Arrest product from a single slab or ingot if this is rolled
Temperature (CAT). directly into plates” as defined in Chapter 1,
Section 1.9.1).
10.1.2 In addition to the required mechanical
properties indicated in Section 3 for EH36, EH40 10.1.4 The chemical composition and
and EH47 steels, brittle crack arrest steels are deoxidation practice for brittle crack arrest steels
to comply with the requirements specified in is indicated in Table 10.1.4.
Table 10.1.3 and Table 10.1.4 of this Section.

Table 10.1.3 : Requirement of brittle crack arrest properties for brittle crack arrest steels

Brittle crack arrest properties2), 6)

Suffix to the Thickness range
Brittle Crack Arrest Toughness Crack Arrest Temperature
steel grade1) [mm]
Kca at -10 °C [N/mm3/2] 3) CAT [°C] 4)
BCA1 50 < t ≤ 100 6,000 min. -10 or below

BCA2 80 < t ≤ 100(7) 8,000 min. See Note 5.

t : thickness [mm]

Notes:

1) Suffix “BCA1” or “BCA2” is to be affixed to the steel grade designation (for e.g. EH40-BCA1,
EH47-BCA1, EH47-BCA2, etc.).

2) Brittle crack arrest properties for brittle crack arrest steels are to be verified by either the brittle
crack arrest toughness Kca or Crack Arrest Temperature (CAT).

3) Kca value is to be obtained by the brittle crack arrest test specified in Chapter 2, Section 5.

4) CAT is to be obtained by the test method specified in Chapter 2, Section 6.

5) Criterion of CAT for brittle crack arrest steels corresponding to Kca=8,000 N/mm3/2 is to be
approved by IRS.

6) Where small-scale alternative tests are used for product testing (batch release testing), these test
methods are to be approved by IRS.

7) Approval for lower thicknesses would be specially considered.

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Table 10.1.4 : Chemical composition and deoxidation practice for brittle

crack arrest steels

Grade EH36-BCA EH40-BCA EH47-BCA

Deoxidation Practice Killed and fine grain treated

Chemical
Composition % 1), 7)
(ladle samples)
C max. 0.18 0.18
Mn 0.90 – 2.00 0.90 – 2.00
Si max. 0.50 0.55
P max. 0.020 0.020
S max. 0.020 0.020
Al (acid soluble min) 0.015 2), 3) 0.015 2), 3)
Nb 0.02 – 0.05 3), 4) 0.02 – 0.05 3), 4)
V 0.05 – 0.10 3), 4) 0.05 – 0.10 3), 4)
Ti max. 0.02(4) 0.02 4)
Cu max. 0.50 0.50
Cr max. 0.25 0.50
Ni max. 2.0 2.0
Mo max. 0.08 0.08
Ceq max.5) 0.47 0.49 0.55
Pcm max.6) - 0.24
Notes :

1. Chemical composition of brittle crack arrest steels is to comply with this

Table, regardless of chemical composition for EH36, EH40 and EH47 steels
specified in Section 3.

2. The total aluminium content may be determined instead of the acid soluble
content. In such cases the total aluminium content is to be not less than
0.020%.

3. The steel is to contain aluminium, niobium, vanadium or other suitable grain

refining elements, either singly or in any combination. When used singly the
steel is to contain the specified minimum content of the grain refining element.
When used in combination, the specified minimum content of a fine graining
element is not applicable.

4. The total niobium, vanadium and titanium content is not to exceed 0.12%.

5. The carbon equivalent Ceq value is to be calculated from the ladle analysis
using the following formula:
Mn Cr  Mo  V Ni  Cu
C eq  C    (%)
6 5 15

6. Cold cracking susceptibility Pcm value is to be calculated using the following

formula:
Si Mn Cu Ni Cr Mo V
Pcm  C         5 B (%)
30 20 20 60 20 15 10

7. Where additions of any other element have been made as part of the
steelmaking practice, the content is to be indicated.

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10.2 Manufacturing Approval Scheme 10.2.3.2 Type of tests

10.2.1 Scope .1 Brittle crack arrest tests are to be carried out

in accordance with 10.2.3.3, in addition to the
The Manufacturing approval scheme for brittle approval tests specified in Part 2 of the IRS
crack steels is to be in accordance with Part 2 of Classification Note: ‘Approval Scheme for the
the IRS Classification Note: ‘Approval Scheme Manufacturing Process of Normal and Higher
for the Manufacturing Process of Normal and Strength Hull Structural Steels’ and/ or Cl.
Higher Strength Hull Structural Steels’ and 3.15.2 of Section 3.
requirements of this sub-section.
.2 In the case of applying for addition of the
10.2.2 Approval application specified brittle crack arrest properties for EH36,
EH40 and EH47 steels of which, manufacturing
10.2.2.1 Documents to be submitted process has been approved by IRS (i.e. The aim
analyses, method of manufacture and condition
The manufacturer is to submit to IRS, the of supply are similar and the steelmaking
following documents together with those process, deoxidation and fine grain practice,
required in Cl. 1.1 of Part 2 of the IRS casting method and condition of supply are the
Classification Note: ‘Approval Scheme for the same), brittle crack arrest tests, chemical
Manufacturing Process of Normal and Higher analyses, tensile test and Charpy V-notch
Strength Hull Structural Steels’: impact test are to be carried out in accordance
with this sub-section and Part 2 of the IRS
a) In-house test reports of the brittle Classification Note: ‘Approval Scheme for the
crack arrest properties of the steels Manufacturing Process of Normal and Higher
intended for approval Strength Hull Structural Steels’:
b) Approval test program for the brittle
crack arrest properties (see 3.1 below) 10.2.3.3 Testing procedure and test specimens
c) Production test procedure for the for brittle crack arrest tests
brittle crack arrest properties.
.1 The test specimens of the brittle crack arrest
10.2.3 Approval tests tests are to be taken with their longitudinal axis
parallel to the final rolling direction of the test
10.2.3.1 Extent of Approval Tests plates.

.1 The extent of the test program is specified in .2 The loading direction of brittle crack tests is to
10.2.3.2 and 10.2.3.3. Cl. 2.1 of Part 2 of the be parallel to the final rolling direction of the test
IRS Classification Note: ‘Approval Scheme for plates.
the Manufacturing Process of Normal and
Higher Strength Hull Structural Steels’ is to be .3 The thickness of the test specimens of the
complied with for the extent of the approval brittle crack arrest tests is to be the full thickness
tests, if the manufacturing process and of the test plates.
mechanism to ensure the brittle crack arrest
properties for the steels intended for approval .4 The test specimens and repeat test
are the same. specimens are to be taken from the same steel
plate.
.2 The number of test samples and test
specimens may be increased when deemed .5 The thickness of the test specimen is to be
necessary by IRS, based on the in-house test the maximum thickness of the steel plate
reports of the brittle crack arrest properties of requested for approval.
the steels intended for approval specified in
10.2.2.1 a).

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.6 In the case where the brittle crack arrest 10.2.5 Approval and Certification
properties are evaluated by Kca, the brittle crack
arrest test method is to be in accordance with 10.2.5.1 Upon satisfactory completion of the
Chapter 2, Section 5. In the case where the survey and tests, approval would be granted by
brittle crack arrest properties are evaluated by IRS with the grade designation having the suffix
CAT, the test method is to be in accordance with “BCA1” or “BCA2” (e.g. EH40-BCA1, EH47-
Chapter 2, Section 6. BCA1, EH47-BCA2, etc.).

10.2.4 Results 10.2.5.2 General conditions for approval and

certification would be in accordance with IRS
10.2.4.1 Part 2, of the IRS Classification Note: Classification Note: ‘Approval Scheme for the
‘Approval Scheme for the Manufacturing Manufacturing Process of Normal and Higher
Process of Normal and Higher Strength Hull Strength Hull Structural Steels’.
Structural Steels’ is to be complied for the
results. 10.2.6 Renewal of approval

10.2.4.2 Additionally, results of test items and 10.2.6.1 The manufacturer is also to submit to
the procedures are to comply with the test IRS actual manufacturing records of the
program approved by IRS. In the case where approved brittle crack arrest steels within the
the brittle crack arrest properties are evaluated term of validity of the manufacturing approval
by Kca or CAT, the manufacturer is to submit to certificate.
IRS, the brittle crack arrest test reports in
accordance with Chapter 2, Section 5 for Kca Note: Chemical composition, mechanical
and Chapter 2 Section 6 for CAT respectively. properties, brittle crack arrest properties (e.g.
brittle crack arrest test results or small-scale
alternative test results) and nominal thickness
are to be described in the form of histogram or
statistics

End of Chapter

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Chapter 4

Steel Castings
Contents
Section
1 General Requirements
2 Hull and Machinery Steel Castings for General Applications
3 Ferritic Steel Castings for Low Temperature Services
4 Steel Castings for Propellers
5 Austenitic Stainless Steel Castings
6 Castings for other applications

Section 1

General Requirements

1.1 Scope 1.2.3 All flame cutting, scarfing or arc-air

gouging to remove surplus metal is to be
1.1.1 All important steel castings, as defined in undertaken in accordance with recognized good
the relevant construction rules are to be practice and is to be carried out before the final
manufactured and tested in accordance with the heat-treatment. Preheating is to be employed
requirements of this Chapter. when necessitated by the chemical composition
and/or thickness of the castings. If necessary,
1.1.2 Where required by the relevant Rules the affected areas are to be either machined or
dealing with design and construction, castings ground smooth.
are to be manufactured and tested in
accordance with Ch.1 and Ch.2, together with 1.2.4 For certain components including steel
the general requirements given in this Section castings subjected to surface hardening
and the appropriate specific requirements given process, the proposed method of manufacture
in Sec.2 to 5. may require special approval by IRS.

1.1.3 As an alternative to 1.1.3, castings which 1.2.5 When two or more castings are joined by
comply with national or proprietary specifications welding to form a composite the proposed
may be accepted provided that these welding procedure is to be submitted for
specifications give reasonable equivalence to approval. Welding procedure qualification tests
the requirements of this chapter or alternatively may be required.
are approved for a specific application.
Generally, survey and certification are to be 1.3 Quality of castings
carried out in accordance with the requirements
of Ch.1. 1.3.1 All castings are to be free from surface or
internal defects which would be prejudicial to
1.2 Manufacture their proper application in service. The surface
finish is to be in accordance with good practice
1.2.1 Castings are to be made by manufacturer and any specific requirements of the approved
approved by IRS. Also refer Chapter 1, Section plan.
1, Cl. 1.3.2.
1.3.2 The surfaces are not to be treated in any
1.2.2 The steel is to be manufactured by a way which may obscure defects.
process approved by IRS.

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1.4 Chemical composition 1.7 Rectification of defective castings

1.4.1 All castings are to be made from killed 1.7.1 General

steel and the chemical composition is to be
appropriate for the type of steel and the i) Steel casting defects are to be removed with
mechanical properties specified for the castings. or without weld repair before considering
The chemical composition of each heat is to be suitable for use subject to approval of IRS.
determined by the manufacturer on a sample
taken preferably during the pouring to the heat. ii) Procedure of removal of defect and weld
When multiple heats are tapped into a common repair is to be in accordance with IRS
ladle, the ladle analysis shall apply. “Classification Notes on Guidelines for Non-
Destructive Testing of Steel Castings for Marine
1.5 Inspection Application.

1.5.1 All castings are to be cleaned and iii) Where the defective area is to be repaired by
adequately prepared for examination; suitable welding, the excavations are to be suitably
methods include pickling, caustic cleaning, wire shaped to allow good access for welding. The
brushing, local grinding, shot or sand blasting. resulting grooves are to be subsequently ground
The surfaces are not to be hammered, peened smooth and complete elimination of the
or treated in any way which may obscure defective material is to be verified by MT or PT.
defects.
iv) Shallow grooves or depressions resulting
1.5.2 Before acceptance all castings are to be from the removal of defects may be accepted
presented to the Surveyors for visual provided that they will cause no appreciable
examination. Where applicable, this is to include reduction in the strength of the casting. The
the examination of internal surfaces. Unless resulting groves or depressions are to be
otherwise agreed, the verification of dimensions subsequently ground smooth and complete
is the responsibility of the manufacturer. elimination of the defective material is to be
verified by MT or PT. Small surface irregularities
1.5.3 When required by the relevant sealed by welding are to be treated as weld
construction Rules, or by the approved repairs.
procedure for welded composite components
appropriate non-destructive testing is also to be v) The manufacturer is to maintain full records
carried out before acceptance and the results detailing the extent and location of repairs made
are to be reported by the manufacturer. The to each casting and details of weld procedures
castings to be examined, extent of testing and and heat treatments applied for repairs. These
acceptance criteria are detailed in IRS records are to be available to the Surveyor and
Classification Notes on “Guidelines for Non- copies provided on request.
Destructive Testing of Steel Castings for Marine
Application. 1.7.2 Weld repairs

1.5.4 When required by the relevant When it has been agreed that a casting can be
construction Rules castings are to be pressure repaired by welding the following requirements
tested before final acceptance. These tests are apply:
to be carried out in the presence of the
Surveyors and are to be to their satisfaction. i) Before welding is started, full details of the
extent and location of the repair, the proposed
1.5.5 In the event of any casting proving welding procedure, heat treatment and
defective during subsequent machining or subsequent inspection procedures are to be
testing, it is to be rejected notwithstanding any submitted for approval:
previous certification.
ii) All castings in alloy steels and all castings for
1.6 Hydraulic pressure testing crankshafts are to be suitably pre-heated prior to
welding. Castings in carbon or carbon-
1.6.1 When required by the relevant manganese steel may also require to be pre-
construction Rules, castings are to be pressure heated depending on their chemical composition
tested before final acceptance. These tests are and the dimensions and position of the weld
to be carried out in the presence of the repairs.
Surveyors and are to be to their satisfaction.

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iii) Welding s to be done under cover in positions 1.8.2 Before acceptance, all castings which
free from draughts and adverse weather have been tested and inspected with
conditions by qualified welders with adequate satisfactory results are to be clearly marked by
supervision. As far as possible, all welding is to the manufacturer with the following particulars:
be carried out in the downhand (flat) position.
i) Steel quality.
iv) The welding consumables used are to be of
an appropriate composition, giving a weld ii) Identification number, cast number or other
deposit with mechanical properties similar and in marking which will enable the full history of the
no way inferior to those of the parent castings. casting to be traced.
Welding procedure tests are to be carried out by
the manufacturer to demonstrate that iii) Manufacturer’s name or trade mark.
satisfactory mechanical properties can be
obtained after heat treatment as detailed in iv) The IRS brand name ‘IR’.
Sec.2.
v) Abbreviated name of the IRS local office.
v) After welding has been completed the
castings are to be given either a suitable heat vi) Personal stamp of Surveyors responsible for
treatment in accordance with the requirements inspection.
of Sec.2 or a stress relieving heat treatment at a
temperature of not less than 550C. The type of vii) Where applicable, test pressure.
heat treatment employed will be dependent on
the chemical composition of the casting and he 1.8.3 When small castings are manufactured in
dimensions, positions and nature of the repairs. large numbers, modified arrangements for
identification may be specially agreed with IRS.
vi) Subject to the prior agreement of IRS special
consideration may be given to the omission of 1.9 Certification
postweld heat treatment or to the acceptance of
local stress relieving heat treatment where the 1.9.1 The manufacturer is to provide the
repaired area is small and machining of the Surveyor with a test certificate or shipping
casting has reached an advanced stage. statement giving the following particulars for
each casting or batch of castings which has
vii) On completion of heat treatment the weld been accepted:-
repairs and adjacent material are to be ground
smooth and examined by magnetic particle or a) Purchaser's name and order number;
liquid penetrant testing. Supplementary
examination by ultrasonics or radiography may b) Description of castings and steel quality;
also be repaired depending on the dimensions
and nature of the original defect. Satisfactory c) Identification number;
results are to be obtained from all forms of non-
destructive testing used. d) Steel making process, cast number and
chemical analysis of ladle samples;
1.8 Identification of castings
e) Results of mechanical testing;
1.8.1 The manufacturer is to adopt a system of
identification which will enable all finished f) General details of heat treatment;
castings to be traced to the original cast and
Surveyors are to be given full facilities for so g) Where applicable, test pressure.
tracing the castings when required.

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Section 2

Hull and Machinery Steel Castings for General Applications

2.1 Scope 2.1.3 Where the use of alloy steel castings is

proposed full details of the chemical
2.1.1 The requirements given in this section are composition, heat treatment, mechanical
applicable to steel castings intended for hull and properties, testing inspection and rectification
machinery applications such as stern frames, are to be submitted for approval of IRS.
rudder frames, crankshafts, turbine casings,
bedplates, etc. 2.2 Chemical composition

2.1.2 These requirements are applicable only to 2.2.1 For carbon and carbon-manganese steel
steel castings where the design and acceptance castings the chemical composition is to comply
tests are related to mechanical properties at with the overall limits given in Table 2.2.1 or
ambient temperature. For other applications, where applicable, the requirements of the
additional requirements may be necessary, approved specification.
especially when the castings are intended for
service at low or elevated temperatures. 2.2.2 Unless otherwise required, suitable grain
refining elements such as aluminium may be
used at the discretion of the manufacturer. The
content of such elements is to be reported.

Table 2.2.1 : Chemical composition limits for hull and machinery steel castings (%)

Steel Applications C Si Mn S P Residual elements (max.) Total

type (max.) (max.) (max.) (max.) Cu Cr Ni Mo residuals
(max.)
Castings for 0.40 0.60 0.50 – 0.040 0.040 0.30 0.30 0.40 0,15 0.80
non-welded 1.60
construction
C,
C-Mn
Castings for 0.23 0.60 1.60 0.040 0.040 0.30 0.30 0.40 0.15 0.80
welded max.
construction

2.3 Heat treatment 2.3.3 Heat treatment is to be carried out in

properly constructed furnaces which are
2.3.1 Castings are to be supplied in one of the efficiently maintained and have adequate means
following conditions: for control and recording of temperature. The
furnace dimensions are to be such as to allow
Fully annealed the whole casting to be uniformly heated to the
Normalised necessary temperature. In the case of very large
Normalised and tempered castings alternative methods for heat treatment
Quenched and tempered will be specially considered by IRS. Sufficient
thermocouples are to be connected to the
The tempering temperature is not less than furnace charge to measure and record that its
550C. temperature is adequately uniform unless the
temperature uniformity of the furnace is verified
2.3.2 Castings or component such as at regular intervals.
crankshafts and engine bedplates, where
dimensional stability and freedom from internal 2.3.4 If a casting is locally reheated or any
stresses are important are to be given a stress straightening operation is performed after the
relief heat treatment. This is to be carried out at final heat treatment, a subsequent stress
a temperature of not less than 550C followed relieving heat treatment may be required in
by furnace cooling to 300C or lower. order to avoid the possibility of harmful residual
stresses.

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2.3.5 The manufacturer’s works is to maintain 2.5 Mechanical properties
records of heat treatment identifying the furnace
used, furnace charge, date, temperature and 2.5.1 Table 2.5.1 gives the minimum
time at temperature. The records are to be requirements for yield stress, elongation and
presented to the Surveyor on request. reduction of area corresponding to different
strength levels. Where it is proposed to use a
2.4 Mechanical tests steel with a specified minimum tensile strength
intermediate to those given, corresponding
2.4.1 Test material, sufficient for the required minimum values for the other properties may be
tests and for possible retest purposes is to be obtained by interpolation.
provided for each casting or batch of castings.
2.5.2 Castings may be supplied to any specified
2.4.2 At least one test sample is to be provided minimum tensile strength selected within the
for each casting. Unless otherwise agreed these general limits detailed in Table 2.5.1 but subject
test samples are to be either integrally cast or to any additional requirements of the relevant
gated to the castings and are to have a construction rules.
thickness of not less than 30 [mm].
2.5.3 The mechanical properties are to comply
2.4.3 Where the casting is of complex design or with the requirements of Table 2.5.1,
where the finished mass exceeds 10 tonnes, appropriate to the specified minimum tensile
two test samples are to be provided. Where strength or, where applicable, the requirements
large castings are made from two or more casts, of the approved specification.
which are not mixed in a ladle prior to pouring,
two or more test samples are to be provided 2.5.4 Where the result of a tensile test does not
corresponding, the number of the casts comply with the requirements, two additional
involved. These are to be integrally cast at tests may be taken. If satisfactory results are
locations as widely separated as possible. obtained from both of these additional tests the
casting or batch of castings is acceptable. If one
2.4.4 For castings where the method of or both retests fail the castings or batch of
manufacture has been specially approved by castings is to be rejected.
IRS in accordance with 1.2.4, the number and
position of test samples is to be agreed with IRS 2.5.5 The additional tests detailed in 2.5.4 are to
having regard to the method of manufacture be taken, preferably from the same, but
employed. alternatively from another, test sample
representative of the casting or batch of
2.4.5 As an alternative to 2.4.2, where a number castings.
of small castings of about the same size, each
of which is under 1000 [kg] in mass are made 2.5.6 At the option of the manufacturer, when a
from one cast and heat treated in the same casting or batch of castings has failed to meet
furnace charge, a batch testing procedure may the test requirements, it may be reheat treated
be adopted using separately cast test samples and re-submitted for acceptance tests.
of suitable dimensions. At least one test sample
is to be provided for each batch of castings. Table 2.5.1 : Mechanical properties for hull and
machinery steel castings
2.4.6 The test samples are not to be detached
from the casting until the specified heat Specified Yield Elongation Reduction
minimum stress on 5.65 of area (%)
treatment has been completed and they have
tensile [N/mm2] So (%) min.
been properly identified. strength min. min.
(1)
2.4.7 One tensile test specimen is to be taken [N/mm2]
from each test sample. 400 200 25 40
440 220 22 30
2.4.8 The preparation of test specimens and the 480 240 20 27
procedures used for mechanical testing are to 520 260 18 25
comply with the relevant requirements of Ch.2. 560 300 15 20
Unless otherwise agreed all tests are to be 600 320 13 20
carried out in the presence of the Surveyors. Note:
(1) A tensile strength range of 150 [N/mm2] may
additionally be specified.

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Section 3

Ferritic Steel Castings for Low Temperature Services

3.1 General 3.1.2 Other steel types may also be accepted

upon consideration in each case.
3.1.1 This Section gives the requirements for
castings in carbon-manganese and nickel alloy 3.2 Chemical composition
steels intended for use in liquefied gas piping
systems where the design temperature is lower 3.2.1 The chemical composition of ladle
than 0C and for other applications where samples is to comply with the overall limits given
guaranteed impact properties at low in Table 3.2.1. The carbon-manganese steel is
temperatures is required. to be fine grain treated.

Table 3.2.1 : Chemical composition of ferritic steel castings for low temperature service

Chemical composition %
Type of Residual
steel C max. Si max. Mn S max. P max. Ni elements
max.
Carbon- 0.25 0.60 0.70-1.60 0.030 0.030 0.80 max.
manganese
2 14 Ni 0.25 0.60 0.50-0.80 0.025 0.030 2.00-3.00 Cr 0.25
Cu 0.30
3 12 Ni 0.15 0.60 0.50-0.80 0.020 0.025 3.00-4.00 Mo 0.15
V 0.03
Total 0.60

3.3 Heat treatment 3.4.3 The average energy value from a set of
three charpy V-notch impact test specimens is
3.3.1 Castings are to be supplied in one of the not to be lower than the required average value
following conditions : given in Table 3.4.1. One individual value may
be less than the required average value
a) normalized. provided that it is not less than 70 per cent of
b) normalized and tempered. this average value.
c) quenched and tempered.
3.5 Non-destructive testing
3.4 Mechanical tests
3.5.1 The non-destructive examination of
3.4.1 The mechanical properties of steel castings is to be carried out in accordance with
castings are to comply with requirements given the appropriate requirements of 1.7 and
in Table 3.4.1. additionally agreed between the manufacturer,
purchaser and Surveyor.

3.4.2 The tensile test is to be carried out at

ambient temperature and the impact tests are to
be carried out at the temperature specified in the
table.

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Table 3.4.1 : Mechanical properties for acceptance purposes : ferritic steel castings for low
temperature service

Charpy V-notch
Yield Elongation
Tensile Reduction impact test
Type of stress on
Grade strength of area % Average
steel [N/mm2] 5.65So% Test
[N/mm2] min. energy J
min. min. temp. Co
min.
Carbon- 400 200 400 - 550 25 40 -60
manganese 430 215 430 - 580 23 35 (see 27
450 230 460 - 610 22 30 Note)
2 14 Ni 490 275 490 - 640 20 35 -70 34
3 12 Ni 490 275 490 - 640 20 35 -95 34
Note : The temperature for carbon-maganese steels may be 5oC
below the design temperature if the
latter is above -55oC, with a maximum test temperature of -20oC.

Section 4

Steel Castings for Propellers

4.1 Scope
a) description of the foundry facilities,
4.1.1 These requirements are applicable to the
manufacture, inspection and repair procedures b) steel material specification,
of cast steel propellers, blades and bosses.
c) runner and feeder arrangements,
4.1.2 Where the use of alternative alloys is
proposed, particulars of chemical composition, d) manufacturing procedures,
mechanical properties and heat treatment are to
be submitted for approval. e)non-destructive testing and repair
procedures.
4.1.3 These requirements may also be used for
the repair of propellers damaged in service, 4.2.3 The scope of the approval test is to be
subject to prior approval of IRS. agreed with IRS. This is to include the
presentation of cast test coupons of the
4.2 Foundry Approval propeller materials in question for approval
testing in order to verify that the chemical
4.2.1 All propellers, blades and bosses are to be composition and the mechanical properties of
manufactured by foundries approved in these materials comply with this section.
accordance with Ch.1. Also refer Chapter 1,
Section 1, Cl. 1.3.2. The castings are to be 4.2.4 The foundry is to have an adequately
manufactured and tested in accordance with the equipped laboratory, manned by experienced
requirements of this Section. personnel, for the testing of moulding materials
chemical analyses, mechanical testing,
4.2.2 It is the manufacturer’s responsibility to microstructural testing of metallic materials and
assure that effective quality, process and non-destructive testing. Where testing activities
production controls during manufacturing are are assigned to other companies or other
adhered to within the manufacturing laboratory, additional information required by
specification. The manufacturing specification is IRS is to be included.
to be submitted to IRS at the time of initial
approval, and is to at least include the following
particulars:

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4.3 Quality of castings 4.3.2 Removal of defects

4.3.1 Freedom from defects 4.3.2.1 Casting defects which may impair the
service performance of the castings, e.g. major
4.3.1.1 All castings are to have a workmanlike non-metallic inclusions, shrinkage cavities, blow
finish and are to be free from imperfections and holes and cracks, are not permitted. They may
defects which would be prejudicial to their be removed by one of the methods described in
proper application in service. Minor casting 4.11 and repaired within the limits and
defects which may still be visible after machining restrictions for the severity zones. Full
such as small sand and slag inclusions, small description and documentation must be
cold shuts and scabs are to be trimmed off by available for the surveyor.
the manufacturer in accordance with 4.11.

Table 4.2.1 : Typical chemical composition for steel propeller castings

Alloy type C max. (%) Mn max. (%) Cr (%) Mo1) max. Ni (%)
(%)
Martensitic (12 Cr 1 Ni) 0.15 2.0 11.5 - 17.0 0.5 Max. 2.0
Martensitic (13 Cr 4 Ni) 0.06 2.0 11.5 - 17.0 1.0 3.5 - 5.0
Martensitic (16 Cr 5 Ni) 0.06 2.0 15.0 - 17.5 1.5 3.5 - 6.0
Austenitic (19 Cr 11 Ni) 0.12 1.6 16.0 - 21.0 4.0 8.0 - 13.0
Note 1) Minimum values are to be in accordance with recognised national or international standards

Table 4.2.2 : Mechanical properties for steel propeller castings

Alloy type Proof stress Tensile Elongation A5 Red. Of area Charpy

Rp0.2 min. strength Rm min. (%) Z min. (%) V-notch1)
[N/mm2] min. [N/mm2] Energy min. (J)
(12 Cr 1 Ni) 440 590 15 30 20
(13 Cr 4 Ni) 550 750 15 35 30
(16 Cr 5 Ni) 540 760 15 35 30
(19 Cr 11 Ni) 1802) 440 30 40 -
Notes:

1) Not required for general service and the lowest ice class notations. For other ice class notations,
tests are to be made -10oC.

2) Rp1.0 value is 205 [N/mm2].

drawing. Dynamic balancing may be necessary

4.4 Dimensions, dimensional and geometri- for propellers running above 500 rpm.
cal tolerances
4.5 Chemical Composition
4.4.1 The verification of dimensions, the
dimensional and geometrical tolerances is the 4.5.1 Typical cast steel propeller alloys are
responsibility of the manufacturer. The report on grouped into four types depending on their
the relevant examinations is to be submitted to chemical composition as given in Table 4.2.1.
the Surveyor, who may require checks to be Cast steel whose chemical composition deviate
made in his presence. from the typical values of Table 4.2.1 must be
specially approved by IRS.
4.4.2 Static balancing is to be carried out on all
propellers in accordance with the approved

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4.5.2 The manufacturer is to maintain records of A, B and C. Definition of skew, and, severity
the chemical analyses of the production casts, zones are given in Ch.8, 3.9.
which are to be made available to the Surveyor
so that he can satisfy himself that the chemical 4.9 Non-destructive examination
composition of each casting is within the
specified limits. 4.9.1 Qualification of personnel involved in NDT

4.6 Heat treatment 4.9.1.1 Refer to IRS Classification Note

“Requirements for NDT Suppliers”.
4.6.1 Martensitic castings are to be austenitized
and tempered. Austenitic castings should be 4.9.2 Visual Testing
solution treated.
4.9.2.1 All finished castings are to be 100%
4.7. Mechanical properties visually inspected by the manufacturer. Castings
are to be free from cracks, hot tears or other
4.7.1 The mechanical properties are to comply imperfections which, due to their nature, degree
with values given in Table 4.2.2. These values or extent, will interfere with the use of the
refer to the test specimens machined from castings. A general visual examination is to be
integrally cast test coupons attached to the hub carried out by the Surveyor.
or on the blade. The thickness of test coupon is
to be in accordance with a recognized standard. 4.9.3 Liquid penetrant testing

4.7.2 Where possible, the test coupons attached 4.9.3.1 Liquid penetrant testing procedure is to
on blades are to be located in an area between be submitted to IRS and is to be in accordance
0.5 to 0.6R, where R is the radius of the with ISO 3452-1:2013 or a recognized standard.
propeller. The acceptance criteria are specified in 4.10.

4.7.3 The test bars are not to be detached from 4.9.3.2 For all propellers, separately cast blades
the casting until the final heat treatment has and hubs, the surfaces covered by severity
been carried out. Removal is to be by non- zones A, B and C are to be liquid penetrant
thermal procedures. tested. Testing of zone A is to be undertaken in
the presence of the Surveyor, whilst testing of
4.7.4 Separately cast test bars may be used zone B and C may be witnessed by the
subject to prior approval of IRS. The test bars Surveyor upon his request.
are to be cast from the same heat as the
castings represented and heat treated with the 4.9.3.3 If repairs have been made either by
castings represented. grinding or by welding, the repaired areas are
additionally to be subjected to the liquid
4.7.5 At least one set of mechanical tests is to penetrant testing independent of their location
be made on material representing each casting and/or severity zone. Weld repairs are,
in accordance with Ch.2. independent of their location, always to be
assessed according to zone A.
4.7.6 As an alternative to 4.7.5, where a number
of small propellers of about the same size, and 4.9.4 Magnetic particle testing
less than 1[m] in diameter, are made from one
cast and heat treated in the same furnace 4.9.4.1 Magnetic particle testing may be used in
charge, a batch testing procedure may be lieu of liquid penetrant testing for examination of
adopted using separately cast test samples of martensitic stainless steels castings. Magnetic
suitable dimensions. At least one set of particle testing procedure is to be submitted to
mechanical tests is to be provided for each IRS and is to be in accordance with ISO 9934-
multiple of five castings in the batch. 1:2016 or a recognized standard.

4.8 Definition of skew, severity zones 4.9.5 Radiographic and ultrasonic testing

4.8.1 In order to relate the degree of inspection 4.9.5.1 When required by IRS or when deemed
to the criticality of imperfections in propeller necessary by the manufacturer, further non-
blades and to help reduce the risk of failure by destructive testing (e.g. radiographic and/or
fatigue cracking after repair, propeller blades are ultrasonic testing) are to be carried out. The
divided into three severity zones designated acceptance criteria or applied quality levels are

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then to be agreed between the manufacturer 4.10.1.5 Aligned indications:

and IRS in accordance with a recognized
standard. a) Non-linear indications form an alignment
Note: due to the attenuating effect of ultrasound when the distance between indications is less
within austenitic steel castings, ultrasonic testing than 2 [mm] and at least three indications are
may not be practical in some cases, depending aligned. An alignment of indications is
on the shape/type/thickness, and grain-growth considered to be a unique indication and its
direction of the casting. length is equal to the overall length of the
alignment.
4.10 Acceptance criteria for liquid penetrant
testing and magnetic particle testing b) Linear indications form an alignment when
the distance between two indications is
4.10.1 Definitions of liquid penetrant indications smaller than the length of the longest
indication.
4.10.1.1 Indication: In the liquid penetrant
testing an indication is the presence of Illustration of liquid penetrant indications is given
detectable bleed-out of the penetrant liquid from in Fig. 4.10.1.
the material discontinuities appearing at least 10
minutes after the developer has been applied. 4.10.2 Acceptance standard

4.10.1.2 Relevant indication: only indications 4.10.2.1 The surface to be inspected is to be

which have any dimension greater than 1.5mm divided into reference areas of 100 [cm2]. Each
shall be considered relevant for the reference area may be square or rectangular
categorization of indications. with the major dimension not exceeding 250
[mm]. The area is to be taken in the most
4.10.1.3 Non-linear indication: an indication unfavourable location relative to the indication
with a largest dimension less than three times its being evaluated.
smallest dimension (i.e. l < 3 w).
4.10.2.2 The relevant indications detected with
4.10.1.4 Linear indication: an indication with a respect to their size and number, are not to
largest dimension three or more times its exceed the values given in the Table 4.10.1.
smallest dimension (i.e. l ≥ 3 w). Areas which are prepared for welding are
independent of their location always to be
assessed according to zone A. The same
applies to the welded areas after being finished
machined and/or grinded.

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Fig.4.10.1 : Shape of indications

Table 4.10.1 : Allowable number and size of relevant indications in a reference area of 100 cm2,
depending on severity zones

Severity zone Max. total Type of Max. number for Max. dimension
number of Indication each type1),2) of indication
indications [mm]
Non-linear 5 4
A 7 Linear 2 3
Aligned 2 3
Non-linear 10 6
B 14 Linear 4 6
Aligned 4 6
Non-linear 14 8
C 20 Linear 6 6
Aligned 6 6

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Table 4.10.1 (Contd.)

Notes:

1) Single non-linear indications less than 2 [mm] in Zone A and less than 3 [mm] for the other zones
are not considered relevant.

2) The total number of non-linear indications may be increased to the maximum total number, or part
thereof, represented by the absence of linear or aligned indications.

4.11 Repair of defects treatment, traceable to each casting. Before

welding is started, full details of the extent and
4.11.1 Defective castings are to be repaired in location of the repair, the proposed welding
accordance with the requirements given in procedure, heat treatment and subsequent
4.11.2 to 4.11.7 and, where applicable, the inspection procedures are to be submitted to the
requirements of 4.12. IRS for approval.

4.11.2 In general the repairs are to be carried 4.12 Welding repair procedure
out by mechanical means, e.g. by grinding,
chipping or milling. The resulting grooves are to 4.12.1 Before welding is started, manufacturer is
be blended into the surrounding surface so as to to submit to IRS a detailed welding procedure
avoid any sharp contours. Complete elimination specification covering the weld preparation,
of the defective material is to be verified by welding positions, welding parameters, welding
liquid penetrant testing, or magnetic particle consumables, preheating, post weld heat
testing, if applicable. treatment and inspection procedures.

4.11.3 Weld repairs are to be undertaken only 4.12.2 All weld repairs are to be carried out in
when they are considered to be necessary and accordance with qualified procedures, and by
have prior approval of the Surveyor. welders who are qualified to a recognized
standard. Welding Procedure Qualification Tests
4.11.4 The excavations are to be suitably are to be carried out in accordance with 4.14
shaped to allow good access for welding. The and witnessed by the Surveyor. Defects to be
resulting grooves are to be subsequently ground repaired by welding are to be ground to sound
smooth and complete elimination of the material according to 4.10. The welding grooves
defective material is to be verified by liquid are to be prepared in such a manner which will
penetrant testing. Welds having an area less allow a good fusion of the groove bottom. The
than 5 [cm2] are to be avoided. resulting ground areas are to be examined in the
presence of the Surveyor by liquid penetrant
4.11.5 Grinding in severity Zone A may be testing in order to verify the complete elimination
carried out to an extent that maintains the blade of defective material.
thickness. Repair welding is generally not
permitted in severity Zone A and will only be 4.12.3 Welding is to be done under controlled
allowed after special consideration. conditions free from draughts and adverse
weather.
4.11.6 Defects in severity Zone B that are not
deeper than t/40 [mm] ("t" is the minimum local 4.12.4 Metal arc welding with electrodes or filler
thickness according to the Rules) or 2 [mm], wire used in the procedure tests is to be used.
whichever is greatest, are to be removed by The welding consumables are to be stored and
grinding. Those defects that are deeper may be handled in accordance with the manufacturer's
repaired by welding subject to prior approval recommendations.
from IRS.
4.12.5 Slag, undercuts and other imperfections
4.11.7 Repair welding is generally permitted in are to be removed before depositing the next
severity Zone C. run.

4.11.8 Repair documentation 4.12.6 The martenistic steels are to be furnace

re-tempered after weld repair. Subject to prior
4.11.8.1 The foundry is to maintain records of approval, however, local stress relieving may be
inspections, welding, and any subsequent heat considered for minor repairs.

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g) Alloy type, heat number and chemical
4.12.7 On completion of heat treatment the weld composition;
repairs and adjacent material are to be ground
smooth. All weld repairs are to be liquid h) Casting identification number;
penetrant tested.
i) Details of time and temperature of heat
4.13 Identification and marking treatment;

4.13.1 The manufacturer is to adopt a system j) Results of the mechanical tests.

for the identification of all castings, which enable
the material to be traced to its original cast. The k) Results of non-destructive tests and details
Surveyor is to be given full facilities for so of test procedure where applicable.
tracing the castings when required. Each
finished casting propeller is to be marked by the 4.14 Welding procedure qualification test for
manufacturer at least with the following repair of cast steel propeller
particulars:
4.14.1 General
a) Heat number or other marking which will
enable the full history of the casting to be 4.14.1.1 This sub-section provides requirements
traced; for qualification tests of welding procedures
intended for the repair of cast steel propellers.
b) Grade of cast material or corresponding
abbreviated designation 4.14.1.2 For the welding procedure approval the
welding procedure qualification tests are to be
c) The IRS certificate number and abbreviated carried out with satisfactory results. The
name of local IRS office; qualification tests are to be carried out with the
same welding process, filler metal, preheating
d) Ice class symbol, where applicable; and stress-relieving treatment as those intended
applied by the actual repair work. Welding
e) Skew angle for high skew propellers; procedure specification is to refer to the test
results achieved during welding procedure
f) Date of final inspection. qualification testing.

4.13.2 The IR stamp is to be put on when the 4.14.1.3 Welding procedures qualified at a
casting has been accepted. manufacturer are valid for welding in workshops
under the same technical and quality
4.14 Document and Certification management.

4.14.1 The manufacturer is to provide the 4.14.2 Test piece and welding of sample
Surveyor with an inspection certificate giving the
following particulars for each casting which has 4.14.2.1 The test assembly, consisting of cast
been accepted: samples, is to be of a size sufficient to ensure a
reasonable heat distribution and according to
a) Purchaser's name and order number; Fig. 4.14.2.1 with the minimum dimensions. The
dimensions and shape of the groove is to be
b) Vessel identification, where known; representative of the actual repair work.

c) Description of the casting with drawing 4.14.2.2 Preparation and welding of test pieces
number; are to be carried out in accordance with the
general condition of repair welding work which it
d) Diameter, number of blades, pitch, direction represents.
of turning;
4.14.2.3 Welding of the test assemblies and
e) Skew angle for high skew propellers; testing of test specimens are to be witnessed by
the Surveyor.
f) Final weight;

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1: Joint preparation and fit-up as detailed in the preliminary Welding

Procedure Specification
a: minimum value 150mm
b: minimum value 350mm
t: material thickness

Fig.4.14.2.1 : Test piece for welding repair procedure

4.14.3 Examinations and tests specimens according to recognized standards

acceptable to IRS may be used. The tensile
4.14.3.1 Test assembly is to be examined non- strength is to meet the specified minimum value
destructively and destructively in accordance of the base material. The location of fracture is
with Table 4.14.3.1 and Fig. 4.14.3.1. to be reported, i.e. weld metal, HAZ or base
material.
4.14.3.2 Non-destructive testing
4.14.3.4 Bend test
.1 Test assembly is to be examined by visual
and liquid penetrant testing, or magnetic particle .1Transverse bend tests for butt joints are to be
testing if applicable, prior to the cutting of test in accordance with Ch.2, or, according to a
specimen. In case, that any post-weld heat recognized standard. The mandrel diameter
treatment is required or specified, non- shall be 4 x thickness except for austenitic
destructive testing is to be performed after heat steels, in which case the mandrel diameter is to
treatment. No cracks are permitted. be 3 x thickness. The bending angle is to be
Imperfections detected by liquid penetrant 180°. After testing, the test specimens are not to
testing, or magnetic particle testing if applicable, reveal any open defects in any direction greater
are to be assessed in accordance with 4.10. than 3 [mm]. Defects appearing at the corners of
a test specimen during testing are to be
4.14.3.3 Tensile test investigated case by case. Two root and two
face bend specimens are to be tested. For
.1Two flat transverse tensile test specimens are thickness 12 [mm] and over, four side bend
be prepared. Testing procedures are to be in specimens may alternatively be tested.
accordance with Ch.2. Alternatively tensile test

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4.14.3.5 Macro-examination additional test piece does not comply with the
relevant requirements, the pWPS (preliminary
.1 Two macro-sections are to be prepared and welding procedure specification) is to be
etched on one side to clearly reveal the weld regarded as not capable of complying with the
metal, the fusion line, and the heat affected requirements without modification.
zone. Cracks and lack of fusion are not
permitted. Imperfections such as slag inclusions, .2 If any test specimens fail to comply with the
and pores greater than 3 [mm] are not relevant requirements for destructive testing due
permitted. to weld imperfections only, two further test
specimens are to be obtained for each one that
4.14.3.6 Impact test failed. These specimens can be taken from the
same test piece if there is sufficient material
.1 Impact test is required, where the base available or from a new test piece, and are to be
material is impact tested. Charpy V-notch test subjected to the same test. If either of these
specimens are to be in accordance with Ch.2. additional test specimens does not comply with
Two sets are to be taken, one set with the notch the relevant requirements, the pWPS is to be
positioned in the center of the weld and one set regarded as not capable of complying with the
with the notch positioned in the HAZ (i.e. the requirements without modification.
mid-point of the notch is to be at 1 [mm] to 2
[mm] from the fusion line), respectively. The test .3 If a tensile test specimen fails to meet the
temperature, and impact energy are to comply requirements, the re-testing is to be in
with the requirement specified for the base accordance with Ch.2.
material.
.4 If there is a single hardness value above the
4.14.3.7 Hardness test maximum values allowed, additional hardness
tests are to be carried out (on the reverse of the
.1 The macro-section representing the start of specimen or after sufficient grinding of the
welding is to be used for HV 10 hardness tested surface). None of the additional hardness
testing. Indentations are to traverse 2 [mm] values is to exceed the maximum hardness
below the surface. At least three individual values required.
indentations are to be made in the weld metal,
the HAZ (both sides) and in the base metal .5 The re-testing of Charpy impact specimens
(both sides). The values are to be reported for are to be carried out in accordance with Ch.2.
information.
.6 Where there is insufficient welded assembly
4.14.3.8 Re-testing remaining to provide additional test specimens,
a further assembly is to be welded using the
.1 If the test piece fails to comply with any of the same procedure to provide the additional
requirements for visual or non-destructive specimens.
testing one further test piece is to be welded and
subjected to the same examination. If this

Table 4.14.3.1 Type of tests and extent of testing

Type of test Extent of testing

Visual testing 100% as per 4.14.3.2
Liquid penetrant testing (1) 100% as per 4.14.3.2
Transverse tensile test Two specimens as per 4.14.3.3
Bend test (2) Two root and two face specimens
as per 4.14.3.4
Macro examination Three specimens as per 4.14.3.5
Impact test Two sets of three specimens as per
4.14.3.6
Hardness test As per 4.14.3.7

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(1) Magnetic particle testing may be used in lieu of liquid penetrant testing
for martensitic
stainless steels.
(2) For t≥12mm, the face and root bend may be substituted by 4 side bend
test specimens.

Fig.4.14.3.1 : Weld test assembly

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4.14.4 Test record
4.14.5.4 Welding position
4.14.4.1 Welding conditions for test assemblies
and test results are to be recorded in welding .1 Approval for a test made in any position is
procedure qualification. Forms of welding restricted to that position.
procedure qualification records may be in
accordance with recognised standards. 4.14.5.5 Welding process

4.14.4.2 A statement of the results of assessing .1 The approval is only valid for the welding
each test piece, including repeat tests, is to be process used in the welding procedure test.
made for each welding procedure qualification Single run is not qualified by multi-run butt weld
records. The relevant items listed for the WPS test used in this Section.
are to be included.
4.14.5.6 Filler metal
4.14.4.3 The welding procedure qualification
record is to be signed by the Surveyor .1 The approval is only valid for the filler metal
witnessing the test and is to include IR used in the welding procedure test.
identification.
4.14.5.7 Heat input
4.14.5 Range of approval
.1 The upper limit of heat input approved is 15%
4.14.5.1 General greater than that used in welding the test piece.
The lower limit of heat input approved is 15%
.1 All the conditions of validity stated below are lower than that used in welding the test piece.
to be met independently of each other. Changes
outside of the ranges specified are to require a 4.14.5.8 Preheating and interpass temperature
new welding procedure test. A qualification of a
WPS obtained by a manufacturer is valid for .1 The minimum preheating temperature is not
welding in workshops or sites under the same to be less than that used in the qualification test.
technical and quality control of that The maximum interpass temperature is not to be
manufacturer. higher than that used in the qualification test.

4.14.5.2 Base metal 4.14.5.9 Post-weld heat treatment

.1 Range of approval for steel cast propeller is .1 The heat treatment used in the qualification
limited to steel grade tested. test is to be specified in pWPS. Holding time
may be adjusted as a function of thickness.
4.14.5.3 Thickness

.1 The qualification of a WPS carried out on a

weld assembly of thickness t is valid for the
thickness range given in Table 4.14.5.3.

Table 4.14.5.3 Range of qualification for

thickness

Thickness of the Range of approval

test piece, t (mm)
15<t≤30 3mm to 2t
t>30 0.5t to 2t or 200mm,
whichever is the
greater

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Section 5

Austenitic Stainless Steel Castings

5.1 Scope composition, mechanical properties and heat

treatment are to be submitted for approval.
5.1.1 This section gives the requirements for
castings in austenitic stainless steels for piping 5.2 Chemical composition
systems in ships for liquefied gases where the
design temperature is not lower than –165C 5.2.1 The chemical composition of ladle
and in bulk chemical carriers. samples is to comply with the requirements
given in Table 5.2.1.
5.1.2 Where it is proposed to use alternative
steels, particulars of the specified chemical

Table 5.2.1 : Chemical composition of austenitic stainless steel castings

Type Chemical composition %

of C max. Si Mn S P Cr Mo Ni Others
steel
304L 0.03 - 8.0-12.0 -
304 0.08 - 8.0-12.0 -
316L 0.03 2.0-3.0 9.0-13.0 -
316 0.08 17.0- 2.0-3.0 9.0-13.0 -
0.20-1.5 0.50-2.0 0.40 max.
21.0
317 0.08 3.0-4.0 9.0-12.0 -
347 0.06 - 9.0-12.0 Nb
(see 8xC0.90
Note)
Note: When guaranteed impact values at low temperature are not required, the maximum carbon content may be
0.08% and the maximum niobium may be 1.00%.

5.3 Heat treatment 5.4.2 The tensile test is to be carried out at

ambient temperature and the results are to
5.3.1 All castings are to be solution treated at a comply with the requirements given in Table
temperature of not less than 1000C and cooled 5.4.2.
rapidly in air, oil or water.
5.4.3 The average value for impact test
5.4 Mechanical tests specimens is to comply with the appropriate
requirements given in Table 5.4.2. One
5.4.1 One tensile test specimen is to be individual value may be less than the required
prepared from material representing each average value provided that it is not less than 70
casting or batch of castings. In addition, where percent of this average value. See Ch.1, 1.10 for
the castings are intended for liquefied gas re-test procedures.
applications, where the design temperature is
lower than –55C, one set of three Charpy V-
notch impact test specimens is to be prepared.

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Table 5.4.2 : Mechanical properties for acceptance purposes : austenitic stainless steel castings

Type of Tensile 1.0% proof Elongation Reduction Charpy V-notch impact

steel strength stress on 5.65 So of area % tests
[N/mm2] [N/mm2] % minimum minimum Test temp. Average
minimum minimum
C energy J
minimum
304L 430 215
26 40 -196 41
304 480 220
316L 430 215
26 40 -196 41
317 480 240
347 480 215 22 35 -196 41

5.5 Intergranular corrosion tests 5.6 Non-destructive examination

5.5.1 Where corrosive conditions are anticipated 5.6.1 The non-destructive examination of
in service, intergranular corrosion tests are castings is to be carried out in accordance with
required on castings in grades 304, 316 and the appropriate requirements of Classification
317. Such tests may not be required for grades Notes “Guidelines for non-destructive testing of
304L, 316L and 347. steel castings for marine application” and
additionally agreed between the manufacturer,
5.5.2 Where an intergranular corrosion test is purchaser and Surveyor.
specified, it is to be carried out in accordance
with the standard referred in 9.6.2 of Chapter 3.

Section 6

Castings for other Applications

6.1 General castings for crankshafts and those intended for

elevated temperature service are to be
6.1.1 Details of chemical composition, heat submitted for approval of IRS.
treatment, mechanical properties of steel

End of Chapter

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Chapter 5

Steel Forgings

Contents
Section
1 General Requirements
2 Hull and Machinery Steel Forgings for General Applications
3 Ferritic Steel Forgings for Low Temperature Service
4 Austenitic Stainless Steel Forgings

Section 1

General Requirements

1.1 Scope 1.2 Manufacture

1.1.1 All important steel forgings, as defined in 1.2.1 Forgings are to be made at the works
the relevant construction Rules, are to be approved by IRS. Also refer Chapter 1, Section
manufactured and tested in accordance with the 1, Cl. 1.3.2.
requirements of this Chapter.
1.2.2 The steel used in the manufacture of
1.1.2 Where required by the relevant Rules forgings is to be made by a process approved
dealing with design and construction, forgings by IRS.
are to be manufactured and tested in
accordance with Ch.1 and 2, together with the 1.2.3 Adequate top and bottom discards are to
general requirements given in this Chapter. be made to ensure freedom from piping and
harmful segregations in the finished forgings.
1.1.3 Alternatively, forgings which comply with
National or proprietary specifications may be 1.2.4 The plastic deformation is to be such as to
accepted provided such specifications give ensure soundness, uniformity of structure and
reasonable equivalence to these requirements satisfactory mechanical properties after heat
or are otherwise specially approved for a treatment. The reduction ratio is to be in
specific application by IRS. accordance with the following Table:

Method of manufacture Total reduction ratio

(See Notes 1, 2 & 3)

Made directly from ingots or forged blooms or 3:1 where L > D

billets 1.5:1 where L  D
Made from rolled products 4:1 where L > D
2:1 where L  D
Notes

1 L and D are the length and diameter respectively of the part of the forging under consideration.
2 the reduction ratio is to be calculated with reference to the average cross-sectional area of the
ingot. Where an ingot is initially upset, this reference area may be taken as the average cross-
sectional area after this operation.
3 For rolled bars used as a substitute for forgings (see 1.1.1) the reduction ratio is not to be less
than 6 : 1
4 For forgings made by upsetting, the length after upsetting is to be not more than one-third of the
length before upsetting or, in the case of an initial forging reduction of at least 1.5:1, not more
than one half of the length before upsetting.

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uniformly heated to the necessary temperature.

1.2.5 For crankshafts, where grain flow is In the case of very large forgings alternative
required in the most favourable direction having methods of heat treatment will be specially
regard to the mode of stressing in service, the considered by IRS.
proposed method of manufacture may required
special approval by IRS. In such cases, tests 1.5.2 Except as provided in 1.5.7 and 1.5.8
may be required to demonstrate that a forgings are to be supplied in one of the
satisfactory structure and grain flow are following conditions:
obtained.
a) Carbon and carbon-manganese steels
1.2.6 The shaping of forgings or rolled slabs and Fully annealed
billets by flame cutting, scarfing or arc-air Normalized
gouging is to be undertaken in accordance with Normalized and tempered
recognized good practice and unless otherwise Quenched and tempered
approved, is to be carried out before the final
heat treatment. Preheating is to be employed b) Alloy steels
when necessitated by the composition and/or Quenched and tempered
thickness of the steel.
For all types of steel the tempering temperature
1.2.7 For certain components, subsequent is not less than 550C. Where forgings for
machining of all flame cut surfaces may be gearing are not intended for surface hardening
required. tempering at lower temperature may be allowed.

1.2.8 When two or more forgings are joined by 1.5.3 Alternatively, alloy steel forgings may be
welding to form a composite component the supplied in the normalized and tempered
proposed welding procedure specification is to condition, in which case the specified
be submitted for approval. Welding procedure mechanical properties are to be agreed with
qualification tests may be required. IRS.

1.3 Quality of forgings Sufficient thermocouples are to be connected to

the furnace charge to measure and record that
1.3.1 All forgings are to be free from surface or its temperature is adequately uniform unless the
internal defects which would be prejudicial to temperature uniformity of the furnace is verified
their proper application in service. at regular intervals.

1.4 Chemical composition 1.5.4 If for any reasons a forging is

subsequently heated for further hot working the
1.4.1 All forgings are to be made from killed forging is to be re-heat treated.
steel, and the chemical composition is to be
appropriate for the type of steel, dimensions and 1.5.5 If any straightening operation is performed
required mechanical properties of the forgings after the final heat treatment, a subsequent
being manufactured. stress relieving heat treatment to avoid harmful
residual stresses is to be carried out, unless
1.4.2 The chemical composition of each heat is otherwise agreed.
to be determined by the manufacturer on a
sample taken preferably during the pouring of 1.5.6 Where it is intended to surface harden
the heat. When multiple heats are tapped into a forgings, full details of the proposed procedure
common ladle, the ladle analysis is applicable. and specification are to be submitted for the
approval of IRS. For the purpose of this
1.5 Heat treatment (including surface approval, the manufacturer may be required to
hardening and straightening) demonstrate by test that the proposed
procedure gives a uniform surface layer of the
1.5.1 At an appropriate stage of manufacture, required hardness and depth and that it does
after completion of all hot working operations, not impair the soundness and properties of the
forgings are to be suitably heat treated to refine steel.
the grain structure and to obtain the required
mechanical properties. Heat treatment is to be 1.5.7 Where induction hardening or nitriding is to
carried out in properly constructed furnaces be carried out after machining, forgings are to
which are efficiently maintained and have be heat treated at an appropriate stage to a
adequate means for control and recording of condition suitable for this subsequent surface
temperature. The furnace dimensions are to be hardening.
such as to allow the whole furnace charge to be
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1.5.8 Where carburizing is to be carried out after
machining, forgings are to be heat treated at an 1.8 Rectification of defective forgings
appropriate stage (generally either by full
annealing or by normalising and tempering) to a 1.8.1 Defects may be removed by grinding or
condition suitable for subsequent machining and chipping and grinding provided the component
carburizing. dimensions are acceptable.
The resulting grooves are to have a bottom
1.5.9 If a forging is locally reheated or any radius of approximately three times the groove
straightening operation is performed after the depth and are to be blended into the
final heat treatment, consideration is to be given surrounding surface so as to avoid any sharp
to a subsequent stress relieving heat treatment. contours. Complete elimination of the defective
material is to be verified by magnetic particle
1.5.10 The manufacturer is to maintain records testing or liquid penetrant testing.
of heat treatment identifying the furnace used,
furnace charge, date, temperature and time at 1.8.2 Repair welding of crankshaft forgings is
the beginning and end of heat treatment cycle. not permitted. In the case of other forgings
The records are to be presented to the Surveyor repair welding may be allowed subject to prior
on request. approval of IRS. In such cases, full details of the
extent and location of the repair, the proposed
1.6 Mechanical tests welding procedure, heat treatment and
subsequent inspection procedures are to be
1.6.1 The requirements of Mechanical tests and submitted for the approval.
mechanical properties are given in Section 2
and 3. 1.8.3 The forging manufacturer is to maintain
records of repairs and subsequent inspections
1.7 Inspection traceable to each forging repaired. The records
are to be presented to the Surveyor on request.
1.7.1 Before acceptance, all forgings are to be
presented to the Surveyors for visual a) Purchaser's name and order number;
examination. Where applicable, this is to include
the examination of internal surfaces and bores. b) Description of forgings and steel quality
Unless otherwise agreed, the verification of the identification number;
dimensions is the responsibility of the
manufacturer. c) Steel making process, cast number and
chemical analysis of ladle sample;
1.7.2 When required by the relevant
construction Rules, or by the approved d) Results of mechanical tests;
procedure for welded composite components
appropriate non-destructive testing is also to be e) General details of heat treatment;
carried out before acceptance and the results
are to be reported by the manufacturer. f) Identification number.

The forgings to be examined, the extent of 1.9 Identification of forgings

testing and acceptance criteria are detailed in
IRS Classification Notes on “Guidelines for Non- 1.9.1 Before acceptance, all forgings, which
Destructive Examination of Hull and Machinery have been tested and inspected with
Steel Forgings”. satisfactory results, are to be clearly marked in
at least one place with the IRS brand IR and the
1.7.3 When required by the conditions of following particulars:
approval for surface hardened forgings, (1.5.6)
additional test samples are to be processed at a) The manufacturer's name or trade mark;
the same time as the forgings which they
represent. These test samples are subsequently b) Identification mark for the grade of steel;
to be sectioned in order to determine the
hardness, shape and depth of the locally c) Identification number and/or initials which
hardened zone and which are to comply with the enable the full history of the forging to be traced;
requirements of the approved specification.
d) Personal stamp of Surveyor responsible for
1.7.4 In the event of any forging proving inspection;
defective during subsequent machining or
testing, it is to be rejected notwithstanding any e) Test pressure, where applicable;
previous certification.
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f) Date of final inspection;

a) Purchaser's name and order number;
g) The 'IRS' name;
b) Description of forgings and steel quality
h) Abbreviated name of IRS local office. identification number;

1.9.2 Where small forgings are manufactured in c) Steel making process, cast number and
large numbers, modified arrangements for chemical analysis of ladle sample;
identification may be specially agreed with IRS.
d) Results of mechanical tests;
1.10 Certification
e) General details of heat treatment;
1.10.1 The manufacturer is to provide the
Surveyor, in duplicate, with a test certificate or f) Identification number.
shipping statement giving the following
particulars for each forging or batch of forgings
which has been accepted:

Section 2

Hull and Machinery Steel Forgings for General Applications

2.1 Scope
2.2 Chemical Composition
2.1.1 The requirements given in this section are
applicable to steel forgings intended for hull and 2.2.1 The chemical composition is to comply
machinery applications such as rudder stocks, with the overall limits given in Tables 2.2.1 and
pintles, propeller shafts, crankshafts, connecting Table 2.2.2 or, where applicable, the
rods, piston rods, gearing etc. Where relevant, requirements of the approved specification.
these requirements are also applicable to
material for forging stock and to rolled bars 2.2.2 At the option of the manufacturer, suitable
intended to be machined into components of grain refining elements such as aluminium,
simple shape. niobium or vanadium may be added. The
content of such elements is to be reported.
2.1.2 These requirements are applicable only to
steel forgings where the design and acceptance 2.2.3 Elements designated as residual elements
tests relate to mechanical properties at ambient in the individual specifications are not to be
temperature. For other applications, additional intentionally added to the steel. The content of
requirements may be necessary especially such elements is to be reported.
when the forgings are intended for service at low
or elevated temperatures.

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Table 2.2.1 : Chemical composition limits 1) for hull steel forgings 6)

Steel C Si Mn P S Cr Mo Ni Cu 4) Total
type residuals
C, C-Mn 0.23 2), 3) 0.45 0.20- 0.035 0.035 0.30 4) 0.15 4) 0.40 4) 0.30 0.85
1.50
Alloy 5) 0.45 5) 0.035 0.035 5) 5) 5) 0.30 -

1) Composition in percentage mass by mass maximum unless shown as a range.

2) The carbon content may be increased above this level provided that the carbon equivalent (Ceq) is

not more than 0.41%, calculated using the following formula:

Mn Cr  Mo  V Ni  Cu
Ceq  C    (%)
6 5 15
3) The carbon content of C and C-Mn steel forgings not intended for welded construction may be 0.65

maximum.
4) Elements are considered as residual elements.
5) Specification is to be submitted for approval.
6) Rudder stocks and pintles should be of weldable quality.

Table 2.2.2 : Chemical composition limits 1) for machinery steel forgings

Steel C Si Mn P S Cr Mo Ni Cu 3) Total
type residuals
C, C-Mn 0.65 2) 0.45 0.30- 0.035 0.035 0.30 3) 0.15 3) 0.40 3) 0.30 0.85
1.50
Alloy 4) 0.45 0.45 0.30- 0.035 0.035 Min Min Min 0.30 -
1.00 0.40 5) 0.15 5) 0.40 5)

1) Composition in percentage mass by mass maximum unless shown as a range or as a minimum.

2) The carbon content of C and C-Mn steel forgings intended for welded construction is to be 0.23

maximum. The carbon content may be increased above this level provided that the carbon equivalent
(Ceq) is not more than 0.41%.
3) Elements are considered as residual elements unless shown as a minimum.
4) Where alloy steel forgings are intended for welded constructions, the proposed chemical composition

is subject to approval by IRS.

5) One or more of the elements is to comply with the minimum content.

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2.3 Mechanical tests direction are to be taken from the end of the
journal (test position C in Fig.2.3.5d). If however,
2.3.1 Adequate number of test coupons are to the journal diameter is 200 [mm] or less the
be provided for carrying out tests including for tests are to be taken in a longitudinal direction
retest purposes, with a cross-sectional area of (test position A in Fig.2.3.5d). Where the
not less than that part of the forging which it finished length of the toothed portion exceed
represents. This test material is to be integral 1.25 [m], one set of tests is to be taken from
with each forging except as provided in 2.3.7 each end.
and 2.3.10. Where batch testing is permitted
according to 2.3.10 the test material may c) Small pinions - Where the finished diameter
alternatively be a production part or separately of the toothed portion is 200 [mm] or less one
forged. Separately forged test material is to set of tests is to be taken in a longitudinal
have a reduction ratio similar to that used for the direction (test position A in Fig.2.3.5d).
forgings represented.
d) Gear wheels - One set of tests is to be taken
2.3.2 For the purpose of these requirements a from each forging in tangential direction (test
set of tests is to consist of one tensile test position A or B in Fig.2.3.5e).
specimen and when required in other sections of
Rules three Charpy V-notch impact test e) Gear wheel rims (made by expanding)
specimens. One set of tests is to be taken from each forging
in a tangential direction (test position A or B in
2.3.3 Test specimens are normally to be cut with Fig.2.3.5.f). Where the finished diameter
their axes either parallel (longitudinal test) or exceeds 2.5 [m] or the mass (as heat treated
tangential (tangential test) to the principal axial excluding test material) exceeds 3 tonnes, two
direction of each product. sets of tests are to be taken from diametrically
opposite positions (test positions A and B in Fig.
2.3.4 Unless otherwise agreed, the longitudinal 2.3.5f). The mechanical properties for
axis of test specimens is to be positioned as longitudinal test are also to be applied.
follows:
f) Pinion sleeves - One set of tests is to be taken
a) for thickness or diameter upto maximum 50 from each forging in tangential direction (test
[mm], the axis is to be at the mid-thickness position A or B in Fig.2.3.5g). Where the finished
or the center of the cross section. length exceeds 1.25 [m] one set of tests is to be
b) for thickness or diameter greater than 50 taken from each end.
[mm], the axis is to be at one quarter
thickness (mid-radius) or 8- [mm], whichever g) Crankwebs
is less, below any heat treated surface. One set of tests is to be taken from each forging
in a tangential direction.
2.3.5 Except as provided in 2.3.10 the number
and direction of tests is to be as follows: h) Solid open die forged crankshafts
One set of tests is to be taken in a longitudinal
a) Hull components such as rudder stocks, direction from the driving shaft end of each
pintles etc. General machinery components forging (test position A in Fig.2.3.5h).
such as shafting, connecting rods, etc. Where the mass (as heat treated but excluding
One set of tests is to be taken from the end of test material) exceeds 3 tonnes tests in a
each forging in a longitudinal direction except longitudinal direction are to be taken from each
that, at the discretion of the manufacture the end (test positions A and B in Fig.2.3.5h).
alternative directions or positions as shown in Where, however, the crankthrows are formed by
Fig.2.3.5a, Fig.2.3.5b and Fig.2.3.5c may be machining or flame cutting, the second set of
used. Where a forging exceeds both 4 tonnes in tests is to be taken in a tangential direction from
mass and 3 [m] in length one set of tests is to be material removed from the crankthrow at the
taken from each end. These limits refer to the end opposite the driving shaft end (test position
‘as forged’ mass and length but excluding the C in Fig.2.3.5h).
test material.
2.3.6 For closed die crankshaft forgings and
b) Pinions - Where the finished machined crankshaft forgings where the method of
diameter of the toothed portion exceeds 200 manufacture has been specially approved in
[mm] one set of tests is to be taken from each accordance with 1.2.5, the number and position
forging in a tangential direction adjacent to the of test specimens is to be agreed with IRS
toothed portion (test position B in Fig.2.3.5d). having regard to the method of manufacture
Where the dimensions preclude the preparation employed.
of tests from this position, tests in a tangential
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2.3.7 When a forging is subsequently divided This test material is to be machined to a

into a number of components, all of which are diameter of D/4 or 60 [mm], whichever is less,
heat treated together in the same furnace where D is the finished diameter of the toothed
charge, for test purposes this may be regarded portion.
as one forging and the number of tests required
is to be related to the total length and mass of For preliminary tests, one set of test material
the original multiple forging. should be given a blank carburizing and it
should undergo same heat treated cycle which
2.3.8 Except for components which are to be the forged material will be subjected to.
carburized or for hollow forgings where the ends
are to be subsequently closed, test material is For final acceptance tests, the second set of test
not to be cut from a forging until all heat material is to be blank carburized and heat
treatment has been completed. treated along with the forgings which they
represent.
2.3.9 When forgings are to be carburized
sufficient test material is to be provided for both At the discretion of the forge master or gear
preliminary tests in the as forged condition and manufacturer test samples of larger cross
for final tests after completion of carburizing. section may be either carburized or blank
carburized, but these are to be machined to the
For this purpose duplicate sets of test material required diameter prior to the final quenching
are to be taken from positions as detailed in and tempering heat treatment.
2.3.5, except that irrespective of the dimensions
or mass of the forging, tests are required from Alternative procedures for testing of forgings
one position only and in the case of forgings which are to be carburized may be specially
with integral journals, are to be cut in a agreed with IRS.
longitudinal direction.
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2.3.10 Normalized forgings with mass upto 1000 2.4.4 At the discretion of IRS hardness tests
[kg] each and quenched and tempered forgings may be required in the following cases:
with mass upto 500 [kg] each may be batch
tested. A batch is to consist of forgings of similar i) Gear forgings after completion of heat
shape and dimensions, made from the same treatment and prior to machining the gear teeth:
heat of steel, heat treated in the same furnace
charge and with a total mass not exceeding 6 The hardness is to be determined at four
tonnes for normalized forgings and 3 tonnes for positions equally spaced around the
quenched and tempered forgings respectively. circumference of the surface where teeth will
subsequently be cut. Where the finished
2.3.11 A batch testing procedure may also be diameter of the toothed portion exceeds 2.5 [m],
used for hot rolled bars. A batch is to consist of the above number of test positions is to be
either: increased to eight. Where the width of a gear
wheel rim forging exceeds 1.25 [m], the
i) material from the same rolled ingot or hardness is to be determined at eight positions
bloom provided that where this is cut at each end of the forging.
into individual lengths, these are all heat
treated in the same furnace charge, or ii) Small crankshaft and gear forgings which
have been batch tested:
ii) bars of the same diameter and heat,
heat treated in the same furnace charge In such cases at least one hardness test is to be
and with a total mass not exceeding 2.5 carried out on each forging.
tonnes.
The results of hardness tests are to be reported
2.3.12 The preparation of test specimens and and, for information purposes, typical Brinell
the procedures used for mechanical testing are hardness values are given in Table 2.4.2.
to comply with the relevant requirements of Pt.2,
Ch.2. Unless otherwise agreed all tests are to 2.4.5 Hardness tests may also be required on
be carried out in the presence of the Surveyor. forgings which have been induction hardened,
nitrided or carburized. For gear forgings these
2.4 Mechanical properties tests are to be carried out on the teeth after,
where applicable, they have been ground to the
2.4.1 Table 2.4.1 and Table 2.4.2 gives the finished profile. The results of such tests
minimum requirements for yield stress, including depth of hardening are to comply with
elongation, reduction of area and impact test the approved specifications. (See 1.5.6).
energy values corresponding to different
strength levels but it is not tended that these 2.4.6 Where the result of a tensile test does not
should necessarily be regarded as specific comply with the requirements, two additional
grades. Where it is proposed to use a steel with tests may be taken. If satisfactory results are
a specified minimum tensile strength obtained from both of these additional tests the
intermediate to those given, corresponding forging or batch of forgings is acceptable. If one
minimum values for the other properties may be or both retests fail the forging or batch of
obtained by interpolation. forgings is to be rejected.

2.4.2 Forgings may be supplied to any specified 2.4.7 Where the results from a set of three
minimum tensile strength selected within the impact test specimens do not comply with the
general limits detailed in Table 2.4.1 and Table requirements an additional set of three impact
2.4.2 but subject to any additional requirements test specimens may be taken provided that not
of the relevant construction rules. more than two individual values are less than
the required average value and of these not
2.4.3 The mechanical properties are to comply more than one is less than 70% of this average
with the requirements of Table 2.4.1 and Table value. The results obtained are to be combined
2.4.2 appropriate to the specified minimum with the original results to form a new average
tensile strength or, where applicable the which, for acceptance of the forgings or batch
requirements of the approved specification. forgings, is to be not less than the required
average value.

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Additionally, for these combined results not representative of the forging or hatch of
more than two individual values are to be less forgings.
than the required average value and of these
not more than one is to be less than 70% of this 2.4.9 At the option of the manufacturer, when a
average value. forging or a batch of forgings has failed to meet
the test requirements, it may be re- heat treated
2.4.8 The additional tests detailed in 2.4.6 and and re-submitted for acceptance tests.
2.4.7 are to be taken, preferably from material
adjacent to the original tests, but alternatively
from another test position or sample

Table 2.4.1 : Mechanical properties for hull steel forgings

Steel type Tensile Yield stress Elongation as min. % Reduction of area Z min.
strength 1) Re min. %
Rm min. [N/mm2] Long. Tang. Long. Tang.
[N/mm2]
C and 400 200 26 19 50 35
C-Mn 440 220 24 18 50 35
480 240 22 16 45 30
520 260 21 15 45 30
560 280 20 14 40 27
600 300 18 13 40 27
Alloy 550 350 20 14 50 35
600 400 18 13 50 35
650 450 17 12 50 35
1) The following ranges for tensile strength may be additionally specified:
specified minimum tensile strength : < 600 [N/mm2]  600 [N/mm2]
tensile strength range : 120 [N/mm2] 150 [N/mm2]

Table 2.4.2 : Mechanical properties for machinery steel forgings 2)

Steel type Tensile Yield Elongation As min Reduction of area Z Hardness

strength1) stress Re % min. % 3)
(Brinell)
Rm min. min. Long. Tang. Long. Tang.
[N/mm2] [N/mm2]
C and C-Mn 400 200 26 19 50 35 110-150
440 220 24 18 50 35 125-160
480 240 22 16 45 30 135-175
520 260 21 15 45 30 150-185
560 280 20 14 40 27 160-200
600 300 18 13 40 27 175-215
640 320 17 12 40 27 185-230
680 340 16 12 35 24 200-240
720 360 15 11 35 24 210-250
760 380 14 10 35 24 225-265
Alloy 600 360 18 14 50 35 175-215
700 420 16 12 45 30 205-245
800 480 14 10 40 27 235-275
900 630 13 9 40 27 260-320
1000 700 12 8 35 24 290-365
1100 770 11 7 35 24 320-385

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Table 2.4.2 (Contd.)

1) The following ranges for tensile strength may be additionally specified:
specified minimum tensile strength : < 600 [N/mm2]  600 [N/mm2]
tensile strength range : 120 [N/mm2] 150 [N/mm2]
2) For propeller shafts intended for ships with ice class notation except the lowest one, Charpy V-notch

impact testing is to be carried out for all steel types at –10C and the average energy value is to be
minimum 27J (longitudinal test). One individual value may be less than the required average value
provided that it is not less than 70% of this average value.
3) The hardness values are typical and are given for information purposes only.

Section 3

Ferritic Steel Forgings for Low Temperature Service

3.1 Scope 3.4 Mechanical tests

3.1.1 The requirements for carbon-manganese 3.4.1 At least one tensile and three V-notch
and nickel steels suitable for low temperature impact test specimens are to be taken from
service are detailed in this section. They are each forging or each batch of forgings. Where
applicable to all forgings with material thickness the dimensions and shape allow, the test
up to and including 50 [mm] used for the specimens are to be cut in a longitudinal
construction of cargo tanks, storage tanks and direction.
process pressure vessels for liquefied gases
and where the design temperature is less than 3.4.2 The impact tests are to be carried out at a
0C, to forgings for the piping systems. temperature appropriate to the type of steel and
for the proposed application. Where forgings are
3.1.2 The requirements are also applicable to intended for ships for liquefied gases the test
forgings for other pressure vessels and pressure temperature is to be in accordance with the
piping systems where the use of steels with requirements given in Table 5.4.1 of Ch.3,
guaranteed impact properties at low Sec.5.
temperatures is required.
3.4.3 The results of all tensile tests are to
3.2 Chemical composition comply with the approved specification.

3.2.1 The chemical composition of ladle 3.4.4 The average energy values for impact
samples is, in general, to comply with the tests are also to comply with the approved
requirements given in Table 3.2.1 of Ch.3. specification and generally with the
requirements of Ch.3, Sec.5. See also Ch.2.
3.3 Heat treatment
3.4.5 For material thickness above 50 [mm], the
3.3.1 Forgings are to be normalized, normalized material properties are to be agreed.
and tempered or quenched and tempered in
accordance with the approved specification. 3.5 Pressure tests

3.5.1 When applicable, pressure tests are to be

carried out in accordance with the requirements
of the relevant construction Rules.

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Section 4

Austenitic Stainless Steel Forgings

4.1 General temperatures of 100C and higher given in

Table 4.2.1 may be used for design purposes.
4.1.1 Forgings in austenitic stainless steels are Verification of these values is not required
acceptable for use in the construction of cargo except for material complying with a National or
tanks, storage tanks and piping systems for proprietary specification in which the elevated
chemicals and liquefied gases. They may also temperature properties proposed for design
be accepted for elevated temperature service in purposes are higher than those given in Table
boilers. 4.2.1.

4.1.2 Where it is proposed to use forgings in 4.3 Non-destructive examination

these types of steels, details of the chemical
composition, heat treatment and mechanical 4.3.1 Non-destructive examination is to be
properties are to be submitted for approval. carried out in accordance with the requirements
These are to comply in general, with the of Classification Notes “Guidelines for non-
requirements of Chapter 3, Section 9 for destructive examination of hull and machinery
austenitic steel plates. steel forgings” or as otherwise agreed between
the manufacturer, purchaser and Surveyor.
4.1.3 Unless otherwise specified, impact tests
are not required for acceptance purposes. 4.4 Intergranular corrosion tests
Where they are required tests are to be made
on longitudinal specimens at minus 196C and 4.4.1 Where corrosive conditions are anticipated
the minimum average energy requirements is to in service, intergranular corrosion tests are
be 41J. required on forgings in Grades 304, 316 and
317. Such tests may not be required for Grades
4.2 Mechanical properties for design 304L, 316L, 321 and 347.
purposes
4.4.2 When an intergranular corrosion test is
4.2.1 Where austenitic stainless steel forgings specified, it is to be carried out in accordance
are intended for service at elevated with the standard referred in Section 9.6.2 of
temperatures, the nominal values for the Chapter 3.
minimum one per cent proof stress at

Table 4.2.1 : Mechanical properties for design purposes : austenitic stainless steels

Nominal 1% proof stress [N/mm2] at a temperature

Grade
100C 150C 200C 250C 300C 350C 400C 450C 500C 550C 600C 650C 700C
304L 168 150 137 128 122 116 110 108 106 102 100 96 93
316L 177 161 149 139 133 127 123 119 115 112 110 107 105
316LN 238 208 192 180 172 166 161 157 152 149 144 142 138
321 192 180 172 164 158 152 148 144 140 138 135 130 124
347 204 192 182 172 166 162 159 157 155 153 151 - -

End of Chapter

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Chapter 6

Steel Pipes and Tubes

Contents
Section

1 General Requirements
2 Seamless Pressure Pipes
3 Welded Pressure Pipes
4 Boiler and Superheater Tubes
5 Tubes and Pipes for Low Temperature Services
6 Austenitic Stainless Steel Pressure Pipes

Section 1

General Requirements

1.1 Scope survey is carried out in accordance with Ch.1 of

this Part.
1.1.1 The requirements of this Chapter are
applicable to boiler tubes, superheater tubes 1.1.6 At the discretion of the Surveyor, a
and pipes intended for use in the construction of modified testing procedure may be adopted for
boilers, pressure vessels and ship and small quantities of materials. In such cases,
machinery pressure piping systems. these may be accepted on the manufacturer's
declared chemical composition and hardness
1.1.2 In addition to specifying mechanical tests or other evidence of satisfactory
properties for the purpose of acceptance testing, properties.
these requirements give details of appropriate
mechanical properties at elevated temperatures 1.1.7 Pipes for Class III pressure systems are to
to be used for design purposes. be manufactured and tested in accordance with
the requirements of an acceptable national
1.1.3 Except for pipes for Class III pressure specification. The manufacturer's test certificate
systems (as defined in Pt.4, Ch.2) all pipes and will be acceptable and is to be provided for each
tubes are to be manufactured and tested in consignment of material. Forge butt welded
accordance with the requirements of Ch.1 and 2 pipes are not acceptable for certain applications
of this Part, the general requirements of this as detailed in Pt.4, Ch.2 and Pt.5, Ch.23.
Section and the appropriate requirements given
in Sec.1 to 5. 1.2 Manufacture

1.1.4 Steels, intended for the cargo and process 1.2.1 Pipes for Class I and II pressure systems,
piping systems of ships for liquefied gases boilers and superheater tubes are to be
where the design temperature is less than 0C, manufactured at works approved by IRS. Also
are to comply with specific requirements of refer Chapter 1, Section 1, Cl. 1.3.2. The steel
Sec.5. used is to be manufactured in accordance with
Ch.3, Sec.1.
1.1.5 Pipes and tubes, which comply with
national or proprietary specifications may be 1.2.2 Unless a particular method is requested by
accepted provided that these specifications give the purchaser, pipes and tubes may be
reasonable equivalence to the requirements of manufactured by any of the following methods:-
this Section or are otherwise specially approved
for a specific application and provided that a) hot finished seamless;

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treated in the same furnace charge in a batch

b) cold finished seamless; type furnace.

c) electric resistance or induction welded; 1.6.3 Where no heat treatment has been carried
out, a batch is to consist of pipes or tubes of the
d) cold finished electric resistance or induction same size manufactured by the same method
welded; from material of the same type of steel.

e) electric fusion welded. 1.6.4 For pipes for class I pressure systems and
boiler and superheater tubes, at least 2 per cent
1.2.3 Care is to be taken during manufacture of the number of lengths in each batch is to be
that the pipe or tube surfaces coming in contact selected at random for the preparation of tests
with any non-ferrous metals or their compounds at ambient temperature.
are not contaminated to such an extent as could
prove harmful during subsequent fabrication and 1.6.5 For pipes for class II pressure systems,
operation. each batch is to contain not more than the
number of lengths given in the following Table.
1.3 Quality Tests are to be carried out on at least one pipe
selected at random from each batch or part
1.3.1 All pipes and tubes are to have a thereof.
workmanlike finish and are to be clean and free
from such surface and internal defects as can Outside diameter Number of pipes
be established by the specified tests. [mm] in a batch
 323.9 200 pipes as made
1.3.2 All pipes and tubes are to be reasonably > 323.9 100 pipes as made
straight. The ends are to be cut nominally
square with the axis of the pipes or tubes, and
are to be free from excessive burrs. 1.7 Test specimens and testing procedures

1.3.3 The tolerances on the wall thickness and 1.7.1 The procedures for mechanical tests and
diameter of pipes and tubes are to be in the dimensions of the test specimens are to be
accordance with an acceptable national / in accordance with Ch.2.
international standards.
1.8 Visual and non-destructive testing
1.4 Chemical composition
1.8.1 All pipes for Class I and II pressure
1.4.1 The requirements for the chemical systems, boiler and superheater tubes are to be
composition of the ladle sample and the presented for visual examination and verification
acceptable method of de-oxidation is to comply of dimensions. The manufacturer is to provide
with the requirements detailed in the relevant adequate lighting conditions to enable an
Section of this Chapter. internal and external examination of the pipes
and tubes to be carried out.
1.5 Heat treatment
1.8.2 For welded pipes and tubes the
1.5.1 All pipes and tubes are to be supplied in manufacturer is to employ suitable non-
the condition detailed in the relevant specific destructive methods for the quality control of the
requirements. welds. It is preferred that this examination is
carried out on a continuous basis.
1.6 Test material
1.9 Hydraulic tests
1.6.1 Pipes and tubes are to be presented for
test in batches. The size of a batch and the 1.9.1 Each pipe and tube is to be subjected to a
number of tests to be performed are dependent hydraulic test at the manufacturer's works.
on the application.
1.9.2 The hydraulic test pressure is to be
1.6.2 Where heat treatment has been carried determined by the following formula, except that
out, a batch is to consist of pipes or tubes of the the maximum test pressure need not exceed 14
same size, manufactured from the same type of [N/mm2].
steel and subjected to the same finishing
treatment in a continuous furnace, or heat

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2st d) Identification number and/or initials which
P
D will enable the full history of the item to be
traced;
where,
e) The personal stamp of the Surveyor
P = test pressure [N/mm2]; responsible for the final inspection.

D = nominal outside diameter [mm]; 1.11.2 It is recommended that hard stamping be

restricted to the end face, but it may be
t = nominal wall thickness [mm]; accepted in other positions in accordance with
national standards and practices.
s = 80 per cent of the specified minimum yield
stress [N/mm2], for ferritic steels and 70 per 1.12 Certification
cent of the specified minimum 1.0 per cent
proof stress [N/mm2] for austenitic steels. 1.12.1 The manufacturer is to provide the
These relate to the values specified for Surveyor with copies of test certificate or
acceptance testing at ambient temperature. shipping statement for all material which has
been accepted.
1.9.3 The test pressure is to be maintained for
sufficient time to permit proof and inspection. 1.12.2 Each test certificate is to contain the
Unless otherwise agreed, the manufacturer's following particulars:-
certificate of satisfactory hydraulic test will be
accepted. Where it is proposed to adopt a test a) Purchaser's name and order number;
pressure other than determined as in 1.9.2, the
proposal will be subject to special consideration. b) The yard number for which the material is
intended, if known;
1.10 Rectification of defects
c) Address to which material is despatched;
1.10.1 Surface imperfections may be removed
by grinding provided that the thickness of the d) Specification or the grade of material;
pipe or tube after dressing is not less than the
required minimum thickness. The dressed area e) Description and dimensions;
is to be blended into the contour of the tube.
f) Identification number and/or initials;
1.10.2 By agreement with the Surveyor, the
repair of minor defects by welding can be g) Cast number and chemical composition of
accepted. Welding procedures, including ladle samples;
preheating, post weld heat treatment and
inspection, are to be to the complete satisfaction h) Mechanical test results, and results of the
of the Surveyor. In all cases, the area is to be intercrystalline corrosion tests where
tested by magnetic particle examination, or in applicable;
case of austenitic steels, by liquid penetrant
examination on completion of welding, heat i) Condition of supply.
treatment and surface grinding.
1.12.3 The chemical composition stated on the
1.11 Identification certificate is to include the content of all the
elements detailed in the specific requirements.
1.11.1 Pipes and tubes are to be clearly marked Where rimmed steel is supplied, this is to be
by the manufacturer in accordance with the stated on the certificate.
requirements of Ch.1. The following details are
to be shown on all materials which have been 1.12.4 When steel is not produced at the pipe or
accepted:- tube mill, a certificate is to be supplied by the
steelmaker stating the process of manufacture,
a) IR; the cast number and the ladle analysis.

b) Manufacturer's name or trade mark; 1.12.5 The works at which the steel was
produced must be approved by IRS. Also refer
c) Identification mark for the specification or Chapter 1, Section 1, Cl. 1.3.2.
grade of steel;

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Section 2

Seamless Pressure Pipes

2.1 General 2.2 Manufacture and chemical composition

2.1.1 Following requirements are applicable for 2.2.1 Tubes are to be manufactured by a
seamless pressure pipes in carbon, carbon- seamless process and may be hot or cold
manganese and low alloy steels. finished.

2.1.2 Where pipes are used for the manufacture 2.2.2 The method of de-oxidation and the
of pressure vessel shells and headers, the chemical composition of ladle samples are to
requirements of forgings in Ch.5 are applicable comply with the appropriate requirements given
where the wall thickness exceeds 40 [mm]. in Table 2.2.1.

2.3 Heat treatment

2.3.1 Pipes are to be supplied in the condition

given in Table 2.3.1.

Table 2.3.1 : Heat treatment

Type of steel Condition of supply

Carbon and carbon-manganese
Hot finished Not finished1
Normalized2
Cold finished Normalized2
Alloy steels
1 Cr 1
Mo Normalized and tempered
2

2 14 Cr 1 Mo
Grade 410 Fully annealed
Grade 490 Normalized and tempered 650-750C
1
Cr 1
Mo 1
V Normalized and tempered
2 2 4
Notes:

1. Provided that the finishing temperature is sufficiently high to soften the material.
2. Normalized and tempered at the option of the manufacturer.

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Table 2.2.1 : Chemical composition of seamless pressure pipes

Type of Gra Method Chemical composition of ladle samples %

steel de of C Si Mn S max P
deoxi- max Residual elements
dation
0.40
320  0.16 - - 0.050 0.050
Semi-
0.70
killed or
0.40
killed
360  0.17  0.35 - 0.045 0.045
0.80 Ni 0.30 max.,
Carbon and 0.40 Cr 0.25 max.,
carbon- 410 Killed  0.21  0.35 - 0.045 0.045 Mo 0.10 max.,
manganese 1.20 Cu 0.30 max.
0.80 Total 0.70 max.
460 Killed  0.22  0.35 - 0.045 0.045
1.40
0.80
490 Killed  0.23  0.35 - 0.045 0.045
1.50
Ni Cr Mo Cu Sn V Al
1 0.10- 0.10- 0.40- 0.30 0.70- 0.45- 0.25 0.03 
1 Cr 2 Mo 440 Killed 0.040 0.040 -
0.18 0.35 0.70 max. 1.10 0.65 max. max. 0.020
1
2 4 Cr 1 410 0.08- 0.10- 0.40- 0.30 2.0- 0.90- 0.25 0.03 
Killed 0.040 0.040 -
490 0.15 0.50 0.70 max. 2.5 1.20 max. max. 0.020
Mo
1 1
Cr 2 0.22
2 0.10- 0.10- 0.40- 0.30 0.30- 0.50- 0.25 0.03 
460 Killed 0.040 0.040 -
1 0.18 0.35 0.70 max. 0.60 0.70 max. max. 0.020
Mo 4 V 0.32

2.4 Mechanical tests adjacent to that used for tests at ambient

temperature and tested in accordance with the
2.4.1 All pipes are to be presented in batches as procedures given in Ch.2. If tubes or pipes of
defined in Sec.1. more than one thickness are supplied from one
cast, the test is to be made on the thickest tube
2.4.2 Each pressure pipe selected for test is to or pipe.
be subjected to tensile and flattening or bend
tests. 2.5.3 As an alternative to 2.5.2, a manufacturer
may carry out an agreed comprehensive test
2.4.3 The results of all mechanical tests are to program for a stated grade of steel to
comply with the appropriate requirements given demonstrate that the specified minimum
in Table 2.4.1. mechanical properties at elevated temperatures
can be consistently obtained. This test program
2.5 Mechanical properties for design is to be carried out under the supervision of the
Surveyors, and the results submitted for
2.5.1 Values for nominal minimum lower yield or assessment and approval. When a manufac-
0.2 per cent proof stress at 50C and higher are turer is approved on this basis, tensile tests at
given in Table 2.5.1 and are intended for design elevated temperatures are not required for
purposes only. Verification of these values is not acceptance purposes, but at the discretion of
required, except for materials complying with the Surveyors, occasional check tests of this
national or proprietary specifications where the type may be requested.
elevated temperature properties used for design
are higher than those given in Table 2.5.1. 2.5.4 Values for the estimated average stress to
rupture in 100,000 hours are given in Table
2.5.2 In such cases, at least one tensile test at 2.5.2 and may be used for design purposes.
the proposed design or other agreed
temperature is to be made on each cast. The
test specimen is to be taken from material

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Table 2.4.1 : Mechanical properties for acceptance purposes : Seamless pressure pipes
(maximum wall thickness 40 mm)

Type of Grade Yield stress Tensile Elongation Flattening Bend test

steel [N/mm2] strength on test diameter of
min. [N/mm2] 5.65So% constant C former
min. (t=
thickness)
Carbon and 320 195 320-440 25 0.10 4t
carbon-
360 215 360-480 24 0.10 4t
manganese
410 235 410-530 22 0.08 4t
460 265 460-580 21 0.07 4t
490 285 490-610 21 0.07 4t
1 Cr
1 440 275 440-590 22 0.07 4t
2
Mo
410 1 135 410-560 20 0.07 4t
2 14 Cr
1 Mo 490 2 275 490-640 16 0.07 4t
1 1
2
Cr 2
Mo
460 275 460-610 15 0.07 4t
1
4
V
Notes:

1 Annealed condition
2 Normalized and tempered condition

Table 2.5.1 : Mechanical properties for design purposes : Seamless pressure pipes

Nominal minimum lower yield or 0.2% proof stress [N/mm2]

Type of Temperature C
Grade
steel
50 100 150 200 250 300 350 400 450 500 550 600
320 172 168 158 147 125 100 91 88 87 - - -
Carbon and 360 192 187 176 165 145 122 111 109 107 - - -
carbon- 410 217 210 199 188 170 149 137 134 132 - - -
manganese 460 241 234 223 212 195 177 162 159 156 - - -
490 256 249 237 226 210 193 177 174 171 - - -
1
1 Cr 2 Mo 440 254 240 230 220 210 183 169 164 161 156 151 -
1
1 410 121 108 99 92 85 80 76 72 69 66 64 62
2 4 Cr 1 Mo
490 2 268 261 253 245 236 230 224 218 205 189 167 145
1 1
2
Cr 2 Mo
460 266 259 248 235 218 192 184 177 168 155 148 -
1
4
V

Notes:

1 Annealed condition

2 Normalized and tempered condition

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Table 2.5.2 : Mechanical properties for design purposes : Seamless pressure pipes - estimated
values for stress to rupture in 100 000 hours (units [N/mm2])

1 1
2
Cr 2 Mo
1 1
Carbon and carbon-manganese 1 Cr 2 Mo 2 4 Cr 1 Mo
1
V
Temperature 4
C Grade 490
Grade 320, 360, Grade 410 Normalized
Grade 460, 490 Grade 440 Grade 460
410 Annealed and tempered
(see Note)
380 171 227 - - - -
390 155 203 - - - -
400 141 179 - - - -
410 127 157 - - - -
420 114 136 - - - -
430 102 117 - - - -
440 90 100 - - - -
450 78 85 - 196 221 -
460 67 73 - 182 204 -
470 57 63 - 168 186 -
480 47 55 210 154 170 218
490 36 47 177 141 153 191
500 - 41 146 127 137 170
510 - - 121 115 122 150
520 - - 99 102 107 131
530 - - 81 90 93 116
540 - - 67 78 79 100
550 - - 54 69 69 85
560 - - 43 59 59 72
570 - - 35 51 51 59
580 - - - 44 44 46
Note : When tempering temperature exceeds 750C, the values for Grade 410 are to be used.

Section 3

Welded Pressure Pipes

3.1 General required, may be subsequently hot reduced or

cold finished.
3.1.1 Following requirements are applicable to
welded pressure pipes in carbon, carbon- 3.2.2 The method of de-oxidation and the
manganese and low alloy steels. chemical composition of ladle samples are to
comply with the appropriate requirements given
3.1.2 Where it is proposed to use submerged in Table 3.2.1.
arc longitudinally welded pipes, details of the
specification are to be submitted. 3.2.3 Where rimmed steel is used, the strips are
to be rolled in single widths and not slit
3.2 Manufacture and chemical composition longitudinally, except to trim the edges.

3.2.1 Pipes are to be manufactured by the

electric or induction welding process and, if

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Table 3.2.1 : Chemical composition of welded pressure pipes

Type of Grade Method Chemical composition of ladle samples %

steel of C Si Mn S P
deoxi- max. max. Residual elements
dation
Any  0.30-
320 - 0.050 0.050
method 0.16 0.70
Carbon
360
(see   0.40-
0.045 0.045
Ni 0.30 max.,
and Note) 0.17 0.35 1.00 Cr 0.25 max.,
carbon- Mo 0.10 max.,
manga- 410 Killed
  0.40-
0.045 0.045 Cu 0.30 max.
0.21 0.35 1.20
nese Total 0.70 max.
460 Killed
  0.80-
0.045 0.045
0.22 0.35 1.40
Ni Cr Mo Cu Sn Al
1
440 Killed
0.10- 0.10- 0.40-
0.040 0.040
0.30 0.70- 0.45- 0.25 0.03 
1 Cr 2 Mo
0.18 0.35 0.70 max. 1.10 0.65 max. max. 0.020
Note : For rimmed steels the carbon content may be increased to 0.19% max.

3.3 Heat treatment

3.4.2 Each pressure pipe selected for test is to
3.3.1 Pipes are to be supplied in the heat be subjected to tensile and flattening or bend
treated condition given in Table 3.3.1. tests.

Table 3.3.1 : Heat treatment : Welded 3.4.3 The results of all mechanical tests are to
pressure pipes comply with the appropriate requirements given
in Table 3.4.1.
Type of steel Condition of supply
Carbon and Normalized (Normalized 3.5 Mechanical properties for design
carbon- and tempered at
manganese the option of the 3.5.1 The mechanical properties at elevated
manufacturer) temperature for carbon and carbon-manganese
steels in Grades 320 [N/mm2] to 460 [N/mm2]
1 Cr 1
Mo Normalized and tempered
2 and 1 Cr 12 Mo steel can be taken from the
appropriate Tables in Sec.2.
3.4 Mechanical tests
3.5.2 Where rimmed steel is used, the design
3.4.1 All pipes are to be presented in batches as temperature is limited to 400C.
defined in Sec.1.

Table 3.4.1 : Mechanical properties for acceptance purposes : Welded pressure pipes

Type of steel Grade Yield stress Tensile Elongation Flattening

[N/mm2] strength on 5.65So% test constant
[N/mm2] minimum C
320 195 320 - 440 25 0.10
Carbon and 360 215 360 - 480 24 0.10
carbon-
410 235 410 - 530 22 0.08
manganese
460 265 460 - 580 21 0.07

1 Cr 1
Mo 440 275 440 - 590 22 0.07
2

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Section 4

Boiler and Superheater Tubes

4.1 General 4.4 Mechanical tests

4.1.1 The following requirements are applicable 4.4.1 Tubes are to be presented for test in
for boiler and superheater tubes in carbon, batches as defined in Sec.1.
carbon-manganese and low alloy steels.
4.4.2 Each boiler and superheater tube selected
4.1.2 Austenitic stainless steels may also be for test is to be subjected to at least the
used for this type of service. Where such following:
applications are proposed, details of the
chemical composition, heat treatment and a) Tensile test;
mechanical properties are to be submitted for
consideration and approval. b) Flattening or bending tests at the
manufacturer's option;
4.2 Manufacture and chemical composition
c) Expanding or flanging tests at the
4.2.1 Tubes are to be seamless or welded and manufacturer's option.
are to be manufactured in accordance with the
requirements of Sec.2 and 3 respectively. 4.4.3 The results of all mechanical tests are to
comply with the appropriate requirements given
4.2.2 The method of de-oxidation and the in Table 4.4.1.
chemical composition of ladle samples are to
comply with the requirements given in Table 4.5 Mechanical properties for design
2.2.1 or Table 3.2.1, as appropriate.
4.5.1 The mechanical properties at elevated
4.3 Heat treatment temperature for carbon and carbon-manganese
steels in Grades 320 [N/mm2] to 460 [N/mm2], 1
4.3.1 All tubes are to be supplied in accordance Cr 12 Mo and 2 14 Cr 1 Mo steels can be taken
with the requirements given in Table 2.3.1 or
from the appropriate Tables in Sec.2.
Table 3.3.1 as appropriate, except that 1 Cr
1
2
Mo steel may be supplied in the normalized 4.5.2 Where rimmed steel is used, the design
only condition when the carbon content does not temperature is limited to 400C.
exceed 0.15 per cent.

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Table 4.4.1 : Mechanical properties for acceptance purposes : Boilers and superheater tubes

Bend Drift expanding and flanging

Elongati
test test minimum % increase in
on on Flatten-
Yield Tensile diame- outside diameter
Type of 5.65So ing test
Grade stress strength ter of Ratio : Inside diameter /
steel % con-
[N/mm2] [N/mm2] former Outside diameter
minimu stant C
(t=thick > 0.6 
m
ness)  0.6 > 0.8
0.8
320 195 320-440 25 0.10 4t 12 15 19
Carbon
and 360 215 360-480 24 0.10 4t 12 15 19
carbon-
410 235 410-530 22 0.08 4t 10 12 17
man-
ganese 460 265 460-580 21 0.07 4t 8 10 15
1 Cr
1
440 275 440-590 22 0.07 4t 8 10 15
2
Mo
1
2 4
Cr 410 1 135 410-560 20 0.07 4t 8 10 15

1 Mo 490 2 275 490-640 16 0.07 4t 8 10 15

Notes:
1. Annealed condition
2. Normalized and tempered condition

Section 5

Tubes and Pipes for Low Temperature Services

5.1 Scope 5.2 Manufacture

5.1.1 This Section gives the requirements for 5.2.1 The pipes are to be manufactured
seamless and welded carbon, carbon- seamless or by a welding process, and may be
manganese and nickel alloy steel pipes not hot or cold finished.
exceeding 25 [mm] in thickness intended for use
in liquefied gas piping systems where the design 5.3 Chemical composition
temperature is lower than 0C and also for other
pressure piping systems where guaranteed 5.3.1 The chemical composition of ladle
impact properties at low temperature is required. samples is in general to comply with the
requirements given in Table 5.3.1. Steels for the
production of tubes and pipes are to be killed.

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Table 5.3.1 : Chemical composition

Method Chemical composition of ladle sample %

Type of Gra of
C P S Residual
steel de deoxi- Si Mn Ni Al met
dation max. max. max. Elements
0.10- 0.40-  0.015 Cr 0.25
Carbon 360 0.17 0.045 0.045 -
0.35 1.00 see note Cu 0.30
Carbon- 410 Mo 0.10
0.10- 0.60-  0.015 Ni 0.30
mangan & 0.2 0.045 0.045 -
Fully 0.35 1.40 see note Total 0.70
ese 460
killed
0.15- 0.30- 3.25- Cr 0.25
3.5 Ni 440 0.15 0.040 0.040 -
0.35 0.90 3.75 Cu 0.30
0.15- 0.30- 8.50- Mo 0.10
9 Ni 690 0.3 0.040 0.040 - Total 0.60
0.30 0.90 9.50

Note : Where a minimum Almet of 0.015% is specified, the determination of the total aluminium is
acceptable provided that the result is not less than 0.018%.

5.4 Heat treatment

- one flattening test or bend test or ring
5.4.1 Pipes are to be supplied in the condition tensile test
given in Table 5.4.1.
- one drift or one ring expanding test
Table 5.4.1 : Heat treatment where appropriate.
Type of Steel Condition of Supply
- Welded tubes and pipes:
Carbon and Hot finished
Carbon-manganese Normalized - one tensile test on the base material
Normalized and
tempered - one tensile test on the weld for pipes
3.5 Ni Normalized with D  508 [mm]
Normalized and
tempered - one set of impact tests
9 Ni Double normalized
and tempered - two flattening tests or bend tests or one
Quenched and ring tensile test (ERW and IW)
tempered
- one drift or one ring expanding test
5.5 Mechanical tests (ERW and IW) -two bend tests (SAW).

5.5.1 All pipes are to be presented for test in 5.5.4 Ring tensile test may be carried out in
batches as defined in Sec.1 pressure piping conformity with ISO 8495 or other equivalent
systems. standard.

5.5.2 At least two percent of the number of 5.5.5 The impact tests are to consist of a set of
lengths in each batch is to be selected at three Charpy V-notch test specimens cut in the
random for the preparation of the tests. longitudinal direction with the notch
perpendicular to the original surface of the pipe.
5.5.3 Each pipe or tube selected for test is to be The dimension of the test specimens are to be
subjected to following tests: in accordance with the requirements of Ch.2.
Impact testing is not required for wall thickness
- Seamless pipes and tubes: below 6 [mm].

- one tensile test 5.5.6 The impact values are to be determined at

the lowest test temperature specified for the
- one set of impact tests steel grade and the wall thickness in question.

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be lower than the required average value given

5.5.7 The results of all mechanical tests are to in Table 5.5.1. One individual value may be less
comply with the appropriate values given in than the required average value provided that it
Table 5.5.1. is not less than 70 per cent of this average
value.
5.5.8 The energy value from a set of three
Charpy V-notch impact test specimens is not to

Table 5.5.1 : Mechanical properties for acceptance purposes

Bend test Charpy V-notch

Elonga-
Yield Tensile Flattening diameter impact tests
Type of tion on
Grade stress strength test of former Test Average
steel 5.65 So%
[N/mm2] [N/mm2] constant C (t=thick- tempera- energy J
min.
ness) ture C minimum
Carbon 360 210 360-480 24 0.10 4t -40 27
Carbon- 410 235 410-530 22 0.08 -50 27
manga- 4t
460 260 460-580 21 0.07 -50 27
nese
3.5 Ni 440 245 440-590 16 0.08 4t -100 27
9 Ni 690 510 690-840 15 0.08 4t -196 39

Section 6

Austenitic Stainless Steel Pressure Pipes

6.1 Scope programme of tests for approval is to be carried

out under the supervision of the Surveyors, and
6.1.1 This section gives the requirements for the results are to be to the satisfaction of IRS.
austenitic stainless steel pipes suitable for use
in the construction of the piping systems for 6.2 Manufacture and chemical composition
chemicals and for liquefied gases where the
design temperature is not less than –165C. 6.2.1 Pipes are to be manufactured by a
seamless or a continuous automatic electric
6.1.2 Austenitic stainless steels are also suitable fusion welding process.
for service at elevated temperatures. Where
such applications are proposed, details of the 6.2.2 Welding is to be in a longitudinal direction,
chemical composition, heat treatment and with or without the addition of filler metal.
mechanical properties are to be submitted for
consideration and approval. See also Pt.4, Ch.2, 6.2.3 The chemical composition of the ladle
1.9.5. samples is to comply with the appropriate
requirements of Table 6.2.1.
6.1.3 Where it is intended to supply seamless
pipes in the direct quenched condition, a

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Table 6.2.1 : Chemical composition

Type Grade Chemical composition of ladle sample %

of
steel
C Si Mn P S Cr Mo Ni Others
max. max. max.
304L 490 0.03 <1.00 <2.00 0.045 0.030 17.0-19.0 - 9.0-13.0 -
316L 490 0.03 <1.00 <2.00 0.045 0.030 16.0-18.5 2.0-3.0 11.0-14.5 -
321 510 0.08 <1.00 <2.00 0.045 0.030 17.0-19.0 - 9.0-13.0 Ti  5 xC  0.80
347 510 0.08 <1.00 <2.00 0.045 0.030 17.0-19.0 - 9.0-13.0 Nb10 x C1.00

6.3 Heat treatment

6.4.2 Each pipe selected for test is to be
6.3.1 Pipes are generally to be supplied by the subjected to tensile and flattening or bend tests.
manufacturer in the solution treated condition
over their full length. 6.4.3 The results of all mechanical tests are to
comply with the appropriate requirements given
6.3.2 Alternatively, seamless pipes may be in Table 6.4.1.
direct quenched immediately after hot forming,
while the temperature of the pipes is not less Where the design temperature is less than
than the specified minimum solution treatment –105C, impact tests are to be carried out on a
temperature. set of three Charpy V-notch specimens. The
tests are to be made on longitudinal specimens
6.4 Mechanical tests at –196C and the average energy is to be not
less than 41 Joules.
6.4.1 All pipes are to be presented in batches as
defined in Section 1 for Class I and II piping
systems.

Table 6.4.1 : Mechanical properties for acceptance purposes

Type of Grade 0.2% 1.0% Tensile Elongation Flattening Bend test

steel proof proof strength on 5.65 test diameter of
stress stress [N/mm2] So % constant former
[N/mm2] [N/mm2] minimum (t=thickness)
(see
Note)
304L 490 175 205 490-690 30 0.09 3t
316L 490 185 215 490-690 30 0.09 3t
321 510 195 235 510-710 30 0.09 3t
347 510 205 245 510-710 30 0.09 3t
Note : The 0.2% proof stress values given for information purposes and unless otherwise agreed are not
required to be verified by test.

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6.5 Intergranular corrosion tests subjected to a bend test through 90 over a
mandrel of diameter equal to twice the thickness
6.5.1 For materials used for piping systems for of the test specimen.
chemicals, intercrystalline corrosion tests are to
be carried out on one per cent of the number of 6.6 Fabricated pipework
pipes in each batch, with a minimum of one
pipe. 6.6.1 Fabricated pipework is to be produced
from material manufactured in accordance with
6.5.2 For pipes with an outside diameter not 6.2, 6.3, 6.4 and 6.5.
exceeding 40 [mm], the test specimens are to
consist of a full cross section. For larger pipes, 6.6.2 Welding is to be carried out in accordance
the test specimens are to be cut as with an approved and qualified procedure by
circumferential strips of full wall thickness and suitably qualified welders.
having a width of not less than 12.5 [mm]. In
both cases, the total surface areas is to be 6.6.3 Fabricated pipework may be supplied in
between 15 and 35 [cm2]. the as-welded condition without subsequent
solution treatment provided that welding
6.5.3 When required, one test of this type is to procedure tests have demonstrated satisfactory
be carried out for each tensile test. The testing material properties including resistance to
is to be carried out in accordance with ASTM intercrystalline corrosion.
A262, practice E, copper-copper sulphate-
sulphuric acid or another recognized standard. 6.6.4 In addition, butt welds are to be subjected
The bent specimen is to be free from cracks to 5 per cent radiographic examination for Class
indicating the presence of intergranular attack. I and 2 per cent for Class II pipes.
The material for the test is to be taken adjacent
to that for the tensile test. 6.6.5 Fabricated pipework in the as-welded
condition and intended for systems located on
6.5.4 After immersion, the full cross-section test deck is to be protected by a suitable corrosion
specimens are to be subjected to a flattening control coating.
test in accordance with the requirements of
Chapter 2. The strip test specimens are to be

End of Chapter

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Chapter 7

Iron Castings

Contents
Section

1 General Requirements

Section 1

General Requirements

1.1 Scope 1.2.2 Suitable mechanical methods are to be

employed for the removal of surplus material
1.1.1 This Chapter gives the requirements for from the castings. Thermal cutting processes
both grey and spheroidal or nodular graphite are not acceptable, except as a preliminary
iron castings intended for ship and machinery operation to the mechanical methods.
construction.
1.2.3 Where castings of the same type are
1.1.2 All important iron castings, as defined in regularly produced in quantity, the manufacturer
the relevant parts of the Rules dealing with is to make any tests necessary to prove the
design and construction, are to be manufactured quality of the prototype castings and is also to
and tested in accordance with the requirements make periodical examinations to verify the
of Ch.1 and 2 and the requirements given in the continued efficiency of the manufacturing
following paragraphs. technique. The Surveyor is to be given the
opportunity to witness these tests.
1.1.3 As an alternative to 1.1.2, castings which
comply with National or Proprietary 1.3 Quality of castings
specifications may be accepted, provided that
such specifications give reasonable equivalence 1.3.1 Castings are to be free from surface or
to these requirements or otherwise are specially internal defects which could be prejudicial to
approved or required by IRS. their proper application in service. The surface
finish is to be in accordance with good practice
1.1.4 Where small castings are produced in and any specific requirements of the approved
large quantities, the manufacturer may adopt plan.
alternative procedure for testing and inspection,
subject to the approval of IRS. 1.4 Chemical composition

1.1.5 These requirements are applicable only to 1.4.1 The chemical composition of the iron used
castings where the design and acceptance tests is left to the discretion of the manufacturer, who
are related to mechanical properties at ambient is to ensure that it is suitable to obtain the
temperature. For other applications additional mechanical properties specified for the castings.
requirements may be necessary, especially
when the castings are intended for service at 1.5 Heat treatment
low or elevated temperatures.
1.5.1 Except as required by 1.5.2, castings may
1.2 Manufacture be supplied in either the as cast or heat treated
condition.
1.2.1 All castings, as designated in1.1.2, are to
be manufactured at foundries approved by IRS.

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1.5.2 For some applications, such as high 1.6.3 At least one test sample is to be provided
temperature service or where dimensional for each casting or batch of castings. A batch
stability is important, castings may be required consists of castings poured from a single ladle
to be given a suitable tempering or stress of metal provided they are all of similar type and
relieving heat treatment. This is to be carried out dimensions. A batch should not normally exceed
after any refining heat treatment and before two tonnes of fettled castings and a single
machining. The special qualities with 350 casting will constitute a batch if its mass is two
[N/mm2] and 400 [N/mm2] nominal tensile tonnes or more.
strength and impact test are to undergo
ferritizing heat treatment. 1.6.4 For continuous melting of same grade of
cast iron in large tonnages the mass of the
1.5.3 Where it is proposed to locally harden the batch may be increased to the output of two
surface of castings, full details of the proposed hours of pouring. If production is carefully
procedure and specifications are to be monitored by systematic checking of the melting
submitted for approval by IRS. process, such as chill testing, chemical analysis
or thermal analysis, test samples may be taken
1.6 Mechanical tests at longer intervals.

1.6.1 Separately cast test samples are to be 1.6.5 For large castings where more than one
used unless otherwise agreed between the ladle of treated metal is used, additional test
manufacturer and the purchaser. The test samples are to be provided so as to be
samples are generally to be one of the standard representative of each ladle used.
types detailed in Fig.1.6.1, Fig.1.6.2 and
Fig.1.6.3 with a thickness of 25 [mm]. Test 1.6.6 All test samples are to be suitably marked
samples of dimensions, other than as detailed in to identify them with the castings which they
Fig.1.6.1 to Fig.1.6.3 may, however, be specially represent.
required for some components. For grey cast
iron the test samples are to be in the form of 1.6.7 Where castings are supplied in the heat
cylindrical bars of 30 [mm] diameter and of treated condition, the test samples are to be
suitable length. When two or more test samples heat treated together with the castings which
are cast simultaneously in a single mould, the they represent.
bars are to be at least 50 [mm] apart as
indicated in Fig.1.6.4. 1.6.8 The test samples are to be cast in moulds
made from the same type of material as used for
1.6.2 Integrally cast samples may be used when the castings and are not to be stripped from the
a casting is more than 20 [mm] thick and its moulds until the metal temperature is below
mass exceeds 200 [kgs] subject to agreement 500C.
between the manufacturer and the purchaser.
The type and location of the test sample are to 1.6.9 One tensile test specimen is to prepared
be selected to provide approximately the same from each test sample. The dimensions of the
cooling conditions as for the casting it test specimens and the testing procedures used
represents. are to be in accordance with Ch.2.

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Fig.1.6.4 : Test sample for grey

cast iron

1.7 Mechanical properties

1.7.1 For grey iron castings, only the tensile

strength is to be determined and the results
obtained are to comply with the minimum value
specified for the castings being supplied. The
specified minimum tensile strength is to be not
less than 200 [N/mm2] and not more than 350
[N/mm2]. The fractured surfaces of all tensile
test specimens are to be granular and grey in
appearance.

1.7.2 For spheroidal or nodular graphite iron

castings the tensile strength and elongation are
to be determined. The results of all tests are to
comply with the requirements of Table 1.7.1, but
subject to any additional requirements of the
relevant construction rules. Typical ranges of
hardness values are also given in Table 1.7.1
and are intended for information purposes.

1.7.3 Retest requirements for tensile tests are to

be in accordance with 1.10 of Chapter 1.

1.8 Visual and non-destructive examination

1.8.1 All castings are to be cleaned and

adequately prepared for examination. The
surfaces are not to be hammered, peened or
treated in any way which may obscure defects.

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Table 1.7.1 : Mechanical properties for acceptance purposes (spheroidal or nodular graphite iron)

Typical Impact Energy

0.2% proof
Specified Minimum Elongation Hardness Typical structure
stress (see Test
Tensile Strength on 5.65So Brinell of matrix (see
Note) Temp. J Min.2
[N/mm2] % min. (see para para 1.9.2)
[N/mm2] C
1.7.2)
370 230 17 120 - 180 - - Ferrite
400 250 12 140 - 200 - - Ferrite
500 320 7 170 - 240 - - Ferrite/Pearlite
Ordinary
qualities 600 370 3 190 - 270 - - Ferrite/Pearlite
700 420 2 230 - 300 - - Pearlite
800 480 2 250 - 350 - - Pearlite or
Tempered
Structure
Special 350 220 223 110 - 170 20 17(14) Ferrite
qualities 400 250 183 140 - 200 20 14(11) Ferrite
Notes:

1. For intermediate values of specified minimum tensile strength, the minimum values for 0.2% proof and
elongation may be obtained by interpolation.

2. The average value measured on 3 Charpy V-notch specimens. One result may be below the average value but
not less than the minimum shown in brackets.

3. In the case of integrally cast samples, the elongation may be 2 percentage points less.

1.8.2 Before acceptance, all castings are to be

visually examined including, where applicable, 1.9.2 Examination of the samples is to show that
the examination of internal surfaces. Unless at least 90 per cent of the graphite is in a
otherwise agreed the verification of dimensions dispersed spheroidal or nodular form. Details of
is the responsibility of the manufacturer. the typical matrix structure are given in Table
1.7.1 and are intended for information purposes
1.8.3 Supplementary examination of castings by only.
suitable non-destructive testing procedures is
generally not required except in circumstances 1.10 Rectification of defective castings
where there is reason to suspect the soundness
of the casting. 1.10.1 At the discretion of the Surveyor, small
surface blemishes may be removed by local
1.8.4 When required by the relevant grinding.
construction Rules, castings are to be pressure
tested before final acceptance. 1.10.2 Subject to the prior approval of the
Surveyor, castings containing local porosity may
1.8.5 Cast crankshafts are to be subjected to a be rectified by impregnation with a suitable
magnetic particle inspection. Crack like plastic filler, provided that the extent of the
indications are not permitted. porosity is such that it does not adversely affect
the strength of the castings.
1.9 Metallographic examination
1.10.3 Repairs by welding are generally not
1.9.1 For spheroidal or nodular graphite iron permitted, but may be considered in special
castings, a representative sample from each circumstances. In such cases, full details of the
ladle of treated metal is to be prepared for proposed repair procedure are to be submitted
metallographic examination. These samples for approval prior to commencement of the
may conveniently be taken from the tensile test proposed rectification.
specimens but alternative arrangement for the
provision of the samples may be adopted
provided that they are taken from the ladle
towards the end of the casting period.

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1.11 Identification of castings g) Date of final inspection.

1.11.1 The manufacturer is to adopt a system of 1.11.3 Where small castings are manufactured
identification which will enable all finished in large numbers, modified arrangements for
castings to be traced to the original ladle of identification may be specially agreed with IRS.
treated metal and the Surveyor is to be given full
facilities for so tracing the castings when 1.12 Certification
required.
1.12.1 The manufacturer is to provide the
1.11.2 Before acceptance, all castings which Surveyor with a written statement giving the
have been tested and inspected with following particulars for each casting or batch of
satisfactory results are to be clearly marked by castings which has been accepted:-
the manufacturer with the following particulars:-
a) Purchaser's name and order no;
a) Grade of cast iron;
b) Description of castings and quality of cast
b) Identification number, or other marking iron;
which will enable the full history of the
casting to be traced; c) Identification number;

c) Manufacturer's name or trade mark; d) Results of mechanical tests;

d) IR and the abbreviated name of the local e) Where applicable, details of heat treatment;
office of IRS;
f) Where specially required, the chemical
e) Personal stamp of the Surveyor responsible analysis of the ladle sample;
for inspection;
g) Where applicable, test pressure.
f) Where applicable, test pressure;

End of Chapter

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Chapter 8

Copper Alloys

Contents
Section

1 General Requirements
2 Castings for Valves and Fittings
3 Castings for Propellers
4 Tubes

Section 1

General Requirements

1.1 Scope 1.1.3 Alternatively, tubes and castings which

comply with National or proprietary
1.1.1 The Rules in this Chapter apply to copper specifications may be accepted provided these
alloys used in castings for valves and fittings, specifications give reasonable equivalence to
propeller castings and tubes. the requirements of this Chapter and provided
that survey is carried out in accordance with the
1.1.2 When required by the relevant parts of the requirements of Ch.1.
Rules, dealing with design and construction,
tubes and castings are to be manufactured and 1.1.4 Where it is proposed to use an alloy which
tested in accordance with the appropriate is not specified in this Chapter, details of
requirements of Ch.1 and 2 and the chemical composition, heat treatment and
requirements of this Chapter. mechanical properties are to be submitted for
approval.

Section 2

Castings for Valves and Fittings

2.1 Scope
2.4 Chemical composition
2.1.1 Following requirements make provision for
copper alloy castings for valves, liner bushes 2.4.1 The chemical composition is to comply
and other fittings intended for use in ship and with the appropriate requirements of Table
machinery construction. 2.4.1.

2.2 Manufacture 2.4.2 Where a cast is wholly prepared from

ingots for which an analysis is already available,
2.2.1 Approval of Works, as required by Ch.1, and provided that no significant alloy additions
for the manufacture of castings, covered by this are made during melting, the ingot maker's
Section, is not required. certified analysis may be accepted subject to
occasional check tests as requested by the
2.3 Quality of castings Surveyors.

2.3.1 All castings are to be free from surface or

internal defects, which could be prejudicial to
their proper application in service.
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Table 2.4.1 : Chemical composition

Chemical composition %
Designation
Cu Sn Zn Pb Ni Mn P Fe Al
90/10 Cu-Sn 9.0- 0.5 0.75 0.5 0.50
Remainder - - -
Phosphor-bronze 11.0 max. max. max. max.
85/5/10 Leaded 2.0 9.0- 2.0 0.10
Remainder 4.0-6.0 - - -
bronze max. 11.0 max. max.
8.5- 1.5 1.0
88/10/2 Gunmetal Remainder 1.0-3.0 - - - -
11.0 max. max.
87/7/3/3 Leaded 2.0
Remainder 6.0-8.0 1.5-3.0 2.5-3.5 - - - -
Gunmetal max.
85/5/5/5 Leaded 2.0
Remainder 4.0-6.0 4.0-6.0 4.0-6.0 - - - -
Gunmetal max.
29.0- 0.5-
70/30 Cu-Ni-Fe Remainder - - - - 0.4-1.0 -
32.0 1.50
9.0-
90/10 Cu-Ni-Fe Remainder - - - 0.5-1.0 - 1.0-1.8 -
11.0
0.10 1.0 0.03 7.0-
Ni-Al-bronze Remainder 3.0-6.0 0.5-4.0 - 2.0-6.0
max. max. max. 11.0
material may be cut from the ends of the
2.5 Heat treatment casting.

2.5.1 At the option of the manufacturer castings 2.6.2 Where castings are supplied in a heat
may be supplied in the 'as cast' or heat treated treated condition, the test samples are to be
condition. similarly heat treated prior to the preparation of
the tensile specimens.
2.6 Mechanical tests
2.6.3 The results of all tests are to comply with
2.6.1 The test material may be separately cast the appropriate requirements given in Table
as a keel block sample in accordance with 2.6.1.
Fig.3.6.1 or as otherwise agreed with the
Surveyor. For liners and bushes, the test

Table 2.6.1 : Mechanical properties for acceptance purposes

Designation 0.2% proof stress Tensile Strength Elongation on

[N/mm2] minimum [N/mm2] minimum 5.65So% minimum
(see Note)
90/10 Cu-Sn Phosphor-bronze 120 250 15
85/5/10 Leaded bronze 100 200 16
88/10/2 Gunmetal 130 270 13
87/7/3/3 Leaded Gunmetal 130 250 16
85/5/5/5 Leaded Gunmetal 100 200 16
70/30 Cu-Ni-Fe 220 420 20
90/10 Cu-Ni-Fe 160 320 20
Ni-Aluminium bronze 240 590 16

Note:

The 0.2% proof stress values are given for information purposes only and, unless otherwise agreed, are
not required to be verified by test.

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2.7 Visual examination 2.10 Identification

2.7.1 All castings must be supplied in a clean 2.10.1 Before acceptance, all castings which
fettled condition. have been tested and inspected with
satisfactory results are to be clearly marked with
2.7.2 Before acceptance, all castings are to be the following details:
presented for visual examination by the
Surveyor. This is to include the examination of a) Identification number, cast number or other
internal surfaces where applicable. markings which will enable the full history of
the casting to be traced;
2.7.3 The accuracy and verification of
dimensions are the responsibility of the b) IR and the abbreviated name of the IRS
manufacturer, unless otherwise agreed. local office;

2.8 Pressure testing c) Personal stamp of the Surveyor responsible

for inspection;
2.8.1 Where required by the relevant
construction Rules, castings are to be pressure d) Test pressure, where applicable;
tested before final acceptance. Unless otherwise
agreed, these tests are to be carried out in the e) Date of final inspection.
presence of the Surveyors and are to be to their
satisfaction. 2.10.2 Where small castings are manufactured
in large numbers, modified arrangements for
2.9 Rectification of defective castings identification may be specially agreed with the
Surveyor.
2.9.1 Minor surface defects may be removed by
grinding provided that the dimensional 2.11 Certification
tolerances are not exceeded.
2.11.1 The manufacturer is to provide the
2.9.2 Proposal to repair a defective casting by Surveyor with a written statement giving the
welding are to be submitted to the Surveyor for following particulars for each casting or batch of
approval before this work is commenced. Such castings which has been accepted:-
proposals are to include details of the extent and
positions of all defects. The Surveyor is to a) Purchaser's name and order no.;
satisfy himself the number and size of the
defects are such that castings can be efficiently b) Description of castings and alloy type;
repaired.
c) Identification number
2.9.3 A statement and/or sketch detailing the
extent and position of all weld repairs is to be d) Type of heat treatment, where applicable;
prepared by the manufacturer as permanent
record. e) Ingot or cast analysis.

2.9.4 Weld repairs to liners in copper alloys 2.11.2 In addition to 2.11.1 the manufacturer is
containing more than 0.5 per cent lead are not to provide a signed statement and/or sketch
permitted. detailing the extent and position of all weld
repairs made to each casting.

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Section 3

Castings for Propellers

3.1 Scope 3.2.3 Scope of the approval test

3.1.1 These requirements are applicable to the 3.2.3.1 The scope of the approval test is to be
manufacture, inspection and repair procedures agreed upon with IRS. This is to include the
of cast copper alloys propellers, blades and presentation of cast test coupons of the
bosses. propeller materials in question for approval
testing in order to verify that the chemical
3.1.2 These requirements may also be used for composition and the mechanical properties of
the repair of propellers damaged in service, these materials comply with these rules.
subject to prior agreement with IRS
3.2.4 Inspection facilities
3.1.3 Where the use of alternative alloys is
proposed, particulars of chemical composition, 3.2.4.1 The foundry is to have an adequately
mechanical properties and heat treatment are to equipped laboratory, manned by experienced
be submitted for approval. personnel, for the testing of moulding materials
chemical analyses, mechanical testing, and
3.2 Foundry approval microstructural testing of metallic materials and
non-destructive testing. Where testing activities
3.2.1 Approval are assigned to other companies or other
laboratory, additional information required by
3.2.1.1 All propellers and propeller components IRS is to be included.
are to be manufactured by foundries approved
in accordance with Ch.1. Also refer Ch.1, Sec.1, 3.3. Moulding and casting
Cl.1.3.2. The castings are to be manufactured
and tested in accordance with the requirements 3.3.1 Pouring
of these rules.
3.3.1.1 The pouring is to be carried out into
3.2.2 Application for approval dried moulds using degassed liquid metal. The
pouring is to be controlled as to avoid
3.2.2.1 It is the manufacturer’s responsibility to turbulences of flow. Special devices and/or
assure that effective quality, process and procedures must prevent slag flowing into the
production controls during manufacturing are mould.
adhered to within the manufacturing
specification. The manufacturing specification is 3.3.2 Stress relieving
to be submitted to IRS at the time of initial
approval, and is to at least include the following 3.3.2.1 Subsequent stress relieving heat
particulars: treatment may be performed to reduce the
residual stresses. For this purpose, the
a) description of the foundry facilities, manufacturer is to submit a specification
containing the details of the heat treatment to
b) copper alloy material specification, IRS for approval. For stress relieving
temperatures and holding times see Tables
c) runner and feeder arrangements, 3.12.3(a) and (b).

d) manufacturing procedures, 3.4 Quality of castings

e) non-destructive testing 3.4.1 Freedom from defects

f) inspection procedures, and 3.4.1.1 All castings must have a workmanlike

finish and are to be free from defects which
g) repair procedures. would be prejudicial to their proper application in
service. Minor casting defects which may still be
visible after machining such as small sand and
slag inclusions, cold shuts and scabs are to be

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trimmed off by the manufacturer in accordance 3.6.2 Metallurgical characteristics
with 3.11.
3.6.2.1 The main constituents of the
3.4.2 Removal of defects microstructure in the copper-based alloys
categories CU 1 and CU 2 are alpha and beta
3.4.2.1 Casting defects which may impair the phase. Important properties such as ductility and
serviceability of the castings, e.g. major non- resistance to corrosion fatigue are strongly
metallic inclusions, shrinkage cavities, blow influenced by the relative proportion of beta
holes and cracks, are not permitted. They may phase (too high a percentage of beta phase
be removed by one of the methods described in having a negative effect on these properties). To
3.11 and repaired within the limits and ensure adequate cold ductility and corrosion
restrictions for the severity zones. Full fatigue resistance, the proportion of beta phase
description and documentation are to be is to be kept low. The concept of the zinc
available for the surveyor. equivalent is to be used as control since it
summarizes the effect of the tendency of various
3.5 Dimensions, dimensional and chemical elements to produce beta phase in the
geometrical tolerances structure.

3.5.1 The verification of dimensions, the 3.6.2.2 The structure of CU 1 and CU 2 type
dimensional and geometrical tolerances is the alloys must contain an alpha phase component
responsibility of the manufacturer. The report on of at least 25 % as measured on a test bar by
the relevant examinations is to be submitted to the manufacturer. The zinc equivalent defined
the Surveyor, who may require checks to be by the following formula is not to exceed a value
made in his presence. of 45 %:

3.5.2 Static balancing is to be carried out on all 100 x %Cu

propellers in accordance with the approved Zinc equivalent  100 -
100  A
drawing. Dynamic balancing is necessary for
propellers running above 500 rpm.
where A is the algebraic sum of the following:
3.6 Chemical composition and metallurgical
characteristics 1 x % Sn

3.6.1 Chemical composition 5 x % Al

3.6.1.1. Typical copper propeller alloys are - 0.5 x % Mn

grouped into the four types CU 1, CU 2, CU 3
and CU 4 depending on their chemical - 0.1 x % Fe
composition as given in Table 3.6.1. Copper
alloys whose chemical composition deviate from - 2.3 x % Ni.
the typical values of Table 3.6.1 are to be
specially approved by IRS. The manufacturer is The negative sign in front of the elements Mn,
to maintain records of the chemical analyses of Fe and Ni signifies that these elements tend to
the production casts, which are to be made reduce the proportion of beta phase.
available to the Surveyor.
The micro structure of alloy types CU 1 and CU
2 is to be verified by determining the proportion
of alpha phase. For this purpose, at least one
specimen is to be taken from each heat. The
proportion of alpha phase is to be determined as
the average value of 5 counts.

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Table 3.6.1 : Typical chemical compositions of cast copper alloy for propellers

Chemical composition of ladle samples %

Alloy Designation
Cu Sn Zn Pb Ni Fe Al Mn
Grade CU1 Manganese
1.5 0.5 1.0
Bronze (high strength 52 - 62 35 - 40 0.5-2.5 0.5-3.0 0.5-4.0
max. max. max.
brass)
Grade CU2 Ni-
1.5 0.5
Manganese Bronze (high 50 - 57 33 - 38 3.0-8.0 0.5-2.5 0.5-2.0 1.0-4.0
max. max.
strength brass)
Grade CU3 Ni- 0.1 1.0 0.03
77 - 82 3.0-6.0 2.0-6.0 7.0-11.0 0.5-4.0
Aluminium Bronze max. max. max.
Grade CU4 Mn - 1.0 6.0 0.05
70 - 80 1.5-3.0 2.0-5.0 6.5-9.0 8.0-20.0
Aluminium Bronze max. max. max.

3.7 Mechanical properties and tests 3.7.3 Tensile tests and specimens

3.7.1 The mechanical properties are to comply 3.7.3.1 Tensile tests and specimens are to be in
with the values in Table 3.7.1. These values are accordance with Ch.2.
applicable to test specimens taken from
separately cast samples in accordance with 3.7.3.2 Generally, the specimens are to be
Figure 3.7.1 or with a recognised standard. taken from separately cast sample pieces in
accordance with 3.7.1. The test samples are to
Note : These properties are a measure of the be cast in moulds made of the same material as
mechanical quality of the metal in each heat and the mould for the propeller and they are to be
they are generally not representative of the cooled down under the same conditions as the
mechanical properties of the propeller casting propeller. At least one tensile test specimen is to
itself which may be upto 30% lower than that of be taken from each ladle. If propellers are
a separately cast test coupon. For integrally cast subjected to a heat treatment the test samples
test specimens the requirements are to be are to be heat treated together with them.
specially agreed with IRS.
3.7.3.3 Where test specimens are to be taken
3.7.2 Other alloys from integrally cast test samples, these are to be
the subject of special agreement with IRS.
3.7.2.1 The mechanical properties of alloys not Wherever possible, the test samples are to be
meeting the minimum values of Table 3.7.1 are located on the blades in an area lying between
to comply with a specification approved by IRS. 0.5 to 0.6 R, where R is the radius of the
propeller. The test sample material is to be
removed from the casting by non thermal
procedures.

H= 100 mm, B=50 mm, L>150 mm, T=15 mm and D = 25 mm

Fig.3.7.1 : Test sample casting

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Table 3.7.1 : Mechanical properties of cast copper alloys for propellers ( separately cast test
coupons)
Alloy Designation 0.2% proof stress Tensile Strength Elongation on
[N/mm2] minimum [N/mm2] minimum 5.65So%
minimum
Grade CU1 Manganese bronze 175 440 20
Grade CU2 Ni-Manganese bronze 175 440 20
Grade CU3 Ni-Aluminium bronze 245 590 16
Grade CU4 Mn-Aluminium bronze 275 630 18
tip and the shaft centreline and a second line
3.8 Definition of skew, severity zones through the shaft centreline which acts as a
tangent to the locus of the mid-points of the
3.8.1 Definition of skew helical blade section. See Fig.3.8.1.

3.8.1.1 The skew of a propeller is defined as High skew propellers have a skew angle greater
follows: than 25, low skew propellers a skew angle of
up to 25.
The maximum skew angle of a propeller blade is
defined as the angle, in projected view of the
blade, between a line drawn through the blade

Fig.3.8.1 : Definition of skew angle

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3.8.2 Severity zones procedure are to be submitted for each instance

in order to obtain such approval.
In order to relate the degree of inspection to the
criticality of defects in propeller blades and to Zone C is a region in which the operating
help reduce the risk of failure by fatigue cracking stresses are low and where the blade
after repair, propeller blades are divided into the thicknesses are relatively small so that repair
three severity zones designated A, B and C. welding is safer and, if made in accordance with
an approved procedure is freely permitted.
Zone A is the region carrying the highest
operating stresses and which, therefore, 3.8.2.1 Low-skew propellers
requires the highest degree of inspection.
Generally, the blade thicknesses are greatest in Zone A is in the area on the pressure side of the
this area giving the greatest degree of restraint blade, from and including the fillet to 0.4R, and
in repair welds and this in turn leads to the bounded on either side by lines at a distance
highest residual stresses in and around any 0,15 times the chord length Cr from the leading
repair welds. High residual tensile stresses edge and 0.2 times Cr from the trailing edge,
frequently lead to fatigue cracking during respectively (see Fig. 3.8.2).Where the hub
subsequent service so that relief of these radius (Rb) exceeds 0.27R, the other boundary
stresses by heat treatment is essential for any of zone A is to be increased to 1.5Rb.
welds made in this zone. Welding is generally
not permitted in Zone A and will only be allowed Zone A also includes the parts of the separate
after special consideration. Every effort is to be cast propeller hub which lie in the area of the
made to rectify a propeller which is either windows as described in Fig. 3.8.4 and the
defective or damaged in this area without flange and fillet area of controllable pitch and
recourse to welding even to the extent of built-up propeller blades as described in Fig.
reducing the scantlings, if this is acceptable. If a 3.8.5.
repair using welding is agreed, postweld stress
relief heat treatment is mandatory. Zone B is on the pressure side the remaining
area up to 0.7R and on the suction side the area
Zone B is a region where the operating stresses from the fillet to 0.7R (see Fig. 3.8.1).
may be high. Welding is to preferably be
avoided but generally is allowed subject to prior Zone C is the area outside 0.7R on both sides of
approval from IRS. Complete details of the the blade. It also includes the surface of the hub
defect / damage and the intended repair of a monoblock propeller and all the surfaces of
the hub of a controllable pitch propeller other
than those designated Zone A above.

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Fig.3.8.2 : Severity zones for integrally cast low skew propellers

3.8.2.2 High-skew propellers 0.4 R. It also includes an area along the trailing
edge on the suction side of the blade from the
Zone A is the area on the pressure face root to 0.9 R and with its inner boundary at 0.15
contained within the blade root-fillet and a line of the chord lengths from the trailing edge. Zone
running from the junction of the leading edge B constitutes the whole of the remaining blade
with the root fillet to the trailing edge at 0.9 R surfaces. Zone A and B are illustrated in Fig.
and at passing through the mid-point of the 3.8.3.
blade chord at 0.7 R and a point situated at 0.3
of the chord length from the leading edge at

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Fig.3.8.3 : Severity zones in blades with skew angles greater than 25o

Fig.3.8.4 : Severity zones for controllable pitch propeller boss

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Fig.3.8.5 : Severity zones for controllable pitch and built-up propeller

Note:
The remaining surface of the propeller blades is to be divided into the severity zones as given for solid
cast propellers (Fig. 3.8.2 and Fig. 3.8.3)

3.9 Non-destructive testing The acceptance criteria are specified in 3.10.

The severity zone A is to be subjected to a liquid
3.9.1 Qualification of personnel involved in NDT penetrant testing in the presence of the
Surveyor.
3.9.1.1 Refer to IRS Classification Note: In zones B and C the liquid penetrant testing is
“Requirements for NDT Suppliers”. to be performed by the manufacturer and may
be witnessed by the Surveyor upon his request.
3.9.2 Visual testing If repairs have been made either by grinding,
straightening or by welding the repaired areas
3.9.2.1 All finished castings are to be 100% are additionally to be subjected to the liquid
visually inspected by the manufacturer. Castings penetrant testing independent of their location
are to be free from cracks, hot tears or other and/or severity zone.
imperfections which, due to their nature, degree
or extent, will interfere with the use of the 3.9.4 Radiographic and ultrasonic testing
castings. A general visual examination is to be
carried out by the Surveyor. 3.9.4.1 When required by IRS or when deemed
necessary by the manufacturer, further non-
3.9.3 Liquid penetrant testing destructive testing (e.g. radiographic and/or
ultrasonic testing) are to be carried out. The
3.9.3.1 Liquid penetrant testing procedure is to acceptance criteria or applied quality levels are
be submitted to IRS and is to be in accordance to be agreed between the manufacturer and IRS
with ISO 3452-1:2013 or a recognized standard. in accordance with a recognized standard.

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Note: due to the attenuating effect of ultrasound

within cast copper alloys, ultrasonic testing may Non-linear indication: an indication with a
not be practical in some cases, depending on largest dimension less than three times its
the shape/type/thickness, and grain-growth smallest dimension (i.e. l < 3 w).
direction of the casting.
Linear indication: an indication with a largest
In such cases, effective ultrasound penetration dimension three or more times its smallest
into the casting is to be practically demonstrated dimension (i.e. l ≥ 3 w).
on the item. This would normally be determined
by way of back-wall reflection, and/or target Aligned indications:
features within the casting.
a) Non-linear indications form an alignment
3.10 Acceptance criteria for liquid penetrant when the distance between indications is less
testing than 2 [mm] and at least three indications are
aligned. An alignment of indications is
3.10.1 Definitions of liquid penetrant considered to be a unique indication and its
indications length is equal to the overall length of the
alignment.
Indication: In the liquid dye penetrant
inspection testing an indication is the presence b) Linear indications form an alignment when
of detectable bleed-out of the penetrant liquid the distance between two indications is
from the material discontinuities appearing at smaller than the length of the longest
least 10 minutes after the developer has been indication.
applied.
Illustration of liquid penetrant indication is given
Relevant indication: Only indications which in Fig. 3.10.1.
have any dimension greater than 1.5 mm are to
be considered relevant for the categorization of
indications.

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Fig.3.10.1 : Shape of indications

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Table 3.10.2 : Allowable number and size of relevant indications in a reference area of 100 [cm2],
depending on severity zones1)

Severity zones Max. total Type of Max. number of Max. acceptable

number of indication each type 1)2) value for "a" or
indications "l" of indications
[mm]
A 7 Non-Linear 5 4
Linear 2 3
Aligned 2 3
B 14 Non-Linear 10 6
Linear 4 6
Aligned 4 6
C 20 Non-Linear 14 8
Linear 6 6
Aligned 6 6
Notes:

1) Singular non-linear indications less than 2 [mm] for zone A and less than 3 [mm] for the other zones
are not considered relevant.

2) The total number of non-linear indications may be increased to the max. total number, or part
thereof, represented by the absence of linear or aligned indications.

3.10.2 Acceptance standard 3.11.2 Repair procedures

3.10.2.1 The surface to be inspected is to be a) In general the repairs are to be carried out
divided into reference areas of 100 [cm2] . Each by mechanical means, e.g. by grinding,
reference area may be square or rectangular chipping or milling. Welding may be applied
with the major dimension not exceeding 250mm. subject to the agreement with IRS if
requirements of 3.11.3, 3.11.4 and/or 3.11.5
The area is to be taken in the most unfavourable will be complied with.
location relative to the indication being
evaluated. b) After milling or chipping grinding is to be
applied for such defects which are not to be
The relevant indications detected, with respect welded. Grinding is to be carried out in such
to their size and number, are not to exceed the a manner that the contour of the ground
values given in the Table 3.10.2. depression is as smooth as possible in
order to avoid stress concentrations or to
3.10.2.2 Areas which are prepared for welding minimise cavitation corrosion. Complete
are, independent of their location, always to be elimination of the defective material is to be
assessed according to Zone A. The same verified by liquid penetrant testing.
applies to the welded areas after being finished
machined and/or ground. c) Welding of areas less than 5 [cm2] is to be
avoided.
3.11 Repair of defects
3.11.3 Repair of defects in zone A
3.11.1 Definitions
a) In zone A, repair welding will generally not
3.11.1.1 Indications exceeding the acceptance be allowed unless specially approved by
standard of Table 3.10.2, cracks, shrinkage IRS. In some cases the propeller designer
cavities, sand, slag and other non-metallic may submit technical documentation to
inclusions, blow holes and other discontinuities propose a modified zone A based on
which may impair the safe service of the detailed hydrodynamic load and stress
propeller are defined as defects and must be analysis for consideration by IRS.
repaired.

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b) Grinding may be carried out to an extent standard. Welding Procedure Qualification Tests
which maintains the blade thickness of the are to be carried out in accordance with 3.16
approved drawing. and witnessed by the Surveyor.

c) The possible repair of defects which are 3.12.2 Defects to be repaired by welding are to
deeper than those referred to above will be be ground to sound material according to 3.11.2.
specially considered by IRS.
3.12.2.1 The welding grooves are to be
3.11.4 Repair of defects in zone B prepared in such a manner which will allow a
good fusion of the groove bottom.The resulting
a) Defects that are not deeper than dB = (t/40) ground areas are to be examined in the
[mm] (t = minimum local rule thickness presence of the Surveyor by liquid penetrant
[mm]) or 2 [mm] (whichever is greater) testing in order to verify the complete elimination
below minimum local rule thickness is to be of defective material.
removed by grinding.
3.12.3 Welding repair procedure
b) Those defects that are deeper than
allowable for removal by grinding may be 3.12.3.1 Metal arc welding is recommended to
repaired by welding. be used for all types of welding repair on cast
copper alloy propellers.
3.11.5 Repair of defects in zone C
Arc welding with coated electrodes and gas-
In zone C, repair welds are generally permitted. shielded metal arc process (GMAW) are
generally to be applied. Argon-shielded tungsten
3.11.6 Repair documentation welding (GTAW) is to be used with care due to
the higher specific heat input of this process.
3.11.6.1 The foundry is to maintain records of
inspections, welding, and any subsequent heat Recommended filler metals, pre-heating and
treatment, traceable to each casting. Before stress relieving temperatures are listed in Table
welding is started, full details of the extent and 3.12.3(a).
location of the repair, the proposed welding
procedure, heat treatment and subsequent 3.12.3.2 All propeller alloys are generally to be
inspection procedures are to be submitted to welded in down-hand (flat) position. Where this
IRS for approval. cannot be done, gas-shielded metal arc welding
is to be carried out.
3.12 Welding repair procedure
The section to be welded is to be clean and dry.
3.12.1 General requirements Flux-coated electrodes are to be dried before
welding according to the maker's instructions.
3.12.1.1 Before welding is started, manufacturer
is to submit to IRS a detailed welding procedure To minimize distortion and the risk of cracking,
specification covering the weld preparation, interpass temperatures are to be kept low
welding parameters, filler metals, preheating especially in the case of CU3 alloys.
and post weld heat treatment and inspection
procedures. Slag, undercuts and other defects are to be
removed before depositing the next run.
3.12.1.2 All weld repairs are to be carried out in
accordance with qualified procedures, and, by
welders who are qualified to a recognized

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Table 3.12.3(a) : Recommended filler metals and heat treatments

Alloy type Filler metal Preheat Interpass Stress relief Hot

temp.C [min] temp.C [max] temp.C straightening
temp.C
Al-bronze 1)
CU1 150 300 350 - 500 500 - 800
Mn-bronze
Al-bronze
CU2 150 300 350 - 550 500 - 800
Ni-Mn-bronze
Al-bronze
CU3 Ni-Al-bronze 2) 50 250 450 - 500 700 - 900
Mn-Al-bronze
CU4 Mn-Al-bronze 100 300 450 - 600 700 - 850
Notes:

1) Ni-Al-bronze and Mn-Al-bronze are acceptable.

2) Stress relieving not required, if filler metal Ni-Al-bronze is used.

Table 3.12.3(b) : Soaking times for stress relief heat treatment of copper alloy propellers

Alloy grade CU1 and CU2 Alloy grade CU3 and CU4
Max. Max.
Stress relief Hours per 25 Hours per 25
recommended recommended
temp.C [mm] thickness [mm] thickness
total time hours total time hours
350 5 15 - -
400 1 5 - -
450 1/2 2 5 15
500 1/4 1 1 5
550 1/4 1.2 1/2 1) 2 1)
600 - - 1/4 1) 1 1)
Note 1) 550C and 600C only applicable for CU4 alloys

3.12.3.3 All welding work is to be carried out 3.12.3.5 The soaking times for stress relief heat
preferably in the shop free from draughts and treatment of copper alloy propellers is to be in
influence of the weather. accordance with Table 3.12.3(b). The heating
and cooling is to be carried out slowly under
3.12.3.4 With the exception of alloy CU3 (Ni-Al- controlled conditions. The cooling rate after any
bronze) all weld repairs are to be stress relief stress relieving heat treatment is not to exceed
heat treated, in order to avoid stress corrosion 50C/hr until the temperature of 200C is
cracking. However, stress relief heat treatment reached.
of alloy CU3 propeller castings may be required
after major repairs in zone B (and specially 3.13 Straightening
approved welding in Zone A) or if a welding
consumable susceptible to stress corrosion 3.13.1 Application of load
cracking is used. In such cases the propeller is
to be either stress relief heat treated in the For hot and cold straightening purposes, static
temperature 450 to 500C or annealed in the loading only is to be used.
temperature range 650 - 800C, depending on
the extent of repair, see Table 3.12.3(a).

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3.13.2 Hot straightening f) Ice class symbol, where applicable

Weld repaired areas may be subject to hot g) Skew angle for high skew propellers.
straightening, provided it can be demonstrated
that weld properties are not impaired by the hot 3.15 Manufacturer’s Certificates
straightening operations.
3.15.1 For each casting propeller the
Straightening of a bent propeller blade or a pitch manufacturer is to supply to the Surveyor a
modification is to be carried out after heating the certificate containing the following details:
bent region and approximately 500 [mm] wide
zones on either side of it to the suggested a) Purchaser and order number
temperature range given in Table 3.12.3.(a).
b) Shipbuilding project number, if known
The heating is to be slow and uniform and the
concentrated flames such as oxy-acetylene and c) Description of the casting with drawing
oxy-propane are not to be used. Sufficient time number
is be allowed for the temperature to become
fairly uniform through the full thickness of the d) Diameter, number of blades, pitch, direction
blade section. The temperature is to be of turning
maintained within the suggested range
throughout the straightening operation. A e) Grade of alloy and chemical composition of
thermocouple instrument or temperature each heat
indicating crayons are to be used for measuring
the temperature. f) Heat or casting number

3.13.3 Cold straightening g) Final weight

Cold straightening is to be used for minor h) Results of non-destructive tests and details of
repairs of tips and edges only. Cold test procedure where applicable
straightening on CU1, CU2 and CU4 bronze is
always to be followed by a stress relieving heat i) Portion of alpha-structure for CU 1 and CU 2
treatment, See Table 3.12.3(a). alloys

3.14 Identification and marking k) Results of the mechanical tests

3.14.1 Identification l) Casting identification Number.

3.14.1.1 The manufacturer is to adopt a system m) Skew angle for high skew propellers, see
for the identification of all castings, which enable 3.8.1.
the material to be traced to its original cast. The
Surveyor is to be given full facilities for so 3.16 Welding procedure qualification tests
tracing the castings when required. for repair of cast copper alloy propeller

3.14.2 Marking 3.16.1 General

3.14.2.1 Each finished casting propeller is to be 3.16.1.1 This sub-section includes the
marked by the manufacturer at least with the requirements for qualification tests of welding
following particulars: procedures intended for the repair of cast
copper alloy propellers.
a) Grade of cast material or corresponding
abbreviated designation 3.16.1.2 For the welding procedure approval the
welding procedure qualification tests are to be
b) Manufacturer’s mark carried out with satisfactory results. The
qualification tests are to be carried out with the
c) Heat number, casting number or another same welding process, filler metal, preheating
mark enabling the manufacturing process to be and stress-relieving treatment as those intended
traced back applied by the actual repair work. Welding
procedure specification (WPS) is to refer to the
d) Date of final inspection test results achieved during welding procedure
qualification testing.
e) IRS certificate number

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3.16.1.3 Welding procedures qualified at a

manufacturer are valid for welding in workshops Table 3.16.3.1 : Type of tests and extent of
under the same technical and quality testing
management. Type of test 1) Extent of testing
Visual testing 100% as per 3.16.2
3.16.2 Test piece and welding of sample Liquid penetrant 100% as per 3.16.2
testing
3.16.2.1 The test assembly, consisting of cast Transverse tensile Two specimens as
samples, is to be of a size sufficient to ensure a test per 3.16.3
reasonable heat distribution and according to Macro examination Three specimens as
Fig. 3.16.2.1 with the minimum dimensions. A per 3.16.4
test sample of minimum 30 mm thickness is to Note 1: bend or fracture test are at the
be used. discretion of IRS.
3.16.2.2 Preparation and welding of test pieces
are to be carried out in accordance with the
general condition of repair welding work which it
represents.

3.16.2.3 Welding of the test assemblies and

testing of test specimens are to be witnessed by
the Surveyor.

Fig.3.16.3.1 : Test Specimen

3.16.3.2 Non-destructive testing

1: Joint preparation and fit-up as detailed in the
.1 The test assembly is to be examined by visual
preliminary welding procedure specification
and liquid penetrant testing prior to the cutting of
a: minimum value 150mm
test specimen. In case, that any post-weld heat
b: minimum value 300mm
treatment is required or specified, non-
t: material thickness.
destructive testing is to be performed after heat
treatment. No cracks are permitted.
Fig.3.16.2.1 : Test piece for welding repair
Imperfections detected by liquid penetrant
procedure
testing are to be assessed in accordance with
3.10.
3.16.3 Examination and tests
3.16.3.3 Tensile test:
3.16.3.1 Test assembly is to be examined non-
destructively and destructively in accordance
.1 Two tensile tests are to be prepared as
with the Table 3.16.3.1 and Fig. 3.16.3.1.
shown in Ch.2. Alternatively tensile test
specimens according to recognized standards
acceptable to IRS may be used. The tensile
strength is to meet the values given in Table
3.16.3.3.

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3.16.3.4 Macroscopic examination .3 If a tensile test specimen fails to meet the
requirements, the re-testing is to be in
Three test specimens are to be prepared and accordance with Ch.2.
etched on one side to clearly reveal the weld
metal, the fusion line and the heat affected zone .4 If there is a single hardness value above the
(Figure 3.16.3.1). A suitable etchant for this maximum values allowed, additional hardness
purpose is: tests are to be carried out (on the reverse of the
specimen or after sufficient grinding of the
5 g iron (III) chloride tested surface). None of the additional hardness
30 ml hydrochloric acid (cone) values is to exceed the maximum hardness
100 ml water. values required.

The test specimens are to be examined for .5 The re-testing of Charpy impact specimens
imperfections present in the weld metal and the are to be carried out in accordance with Ch.2.
heat affected zone. Cracks and lack of fusion
are not permitted. Imperfections such as .6 Where there is insufficient welded assembly
pores, or slag inclusions, greater than 3 [mm] remaining to provide additional test specimens,
are not permitted. a further assembly is to be welded using the
same procedure to provide the additional
specimens.
Table 3.16.3.3 : Required tensile strength
values 3.16.4 Test record

Alloy Type Tensile strength 3.16.4.1 Welding conditions for test assemblies
[N/mm2] min and test results are to be recorded in welding
CU 1 370 procedure qualification record. Forms of welding
procedure qualification records may be in
CU 2 410
accordance with recognised standards.
CU 3 500
CU 4 550 3.16.4.2 A statement of the results of assessing
each test piece, including repeat tests, is to be
made for each welding procedure qualification
3.16.3.5 Re-testing records. The relevant items listed for the WPS
are to be included.
.1 If the test piece fails to comply with any of the
requirements for visual or non-destructive 3.16.4.3 The welding procedure qualification
testing one further test piece is to be welded and record is to be signed by the Surveyor
subjected to the same examination. If this witnessing the test and is to include the IR
additional test piece does not comply with the identification.
relevant requirements, the pWPS (preliminary
welding procedure specification) is to be 3.16.5 Range of approval
regarded as not capable of complying with the
requirements without modification. 3.16.5.1 General

.2 If any test specimens fail to comply with the .1 All the conditions of validity stated below are
relevant requirements for destructive testing due to be met independently of each other. Changes
to weld imperfections only, two further test outside of the ranges specified are to require a
specimens are to be obtained for each one that new welding procedure test. A qualification of a
failed. These specimens can be taken from the WPS obtained by a manufacturer is valid for
same test piece if there is sufficient material welding in workshops or sites under the same
available or from a new test piece, and are to be technical and quality control of that
subjected to the same test. If either of these manufacturer.
additional test specimens does not comply with
the relevant requirements, the pWPS is to be
regarded as not capable of complying with the
requirements without modification.

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3.16.5.2 Base metal 3.16.5.5 Welding process

.1 The range of qualification related to base .1 The approval is only valid for the welding
metal is given in Table 3.16.5.2. process used in the welding procedure test.
Single run is not qualified by multi-run butt weld
Table 3.16.5.2 : Range of qualification for test used in this section
base metal
Copper alloy Range of approval 3.16.5.6 Filler metal
material grade used
for qualification .1 The approval is only valid for the filler metal
CU1 CU1 used in the welding procedure test.
CU2 CU1& CU2
CU3 CU3 3.16.5.7 Heat input
CU4 CU4
.1 The upper limit of heat input approved is 25%
3.16.5.3 Thickness greater than that used in welding the test piece.
The lower limit of heat input approved is 25%
.1 The qualification of a WPS carried out on a lower than that used in welding the test piece.
weld assembly of thickness t is valid for the
thickness range given in Table 3.16.5.3. 3.16.5.8 Preheating and interpass temperature

Table 3.16.5.3 : Range of qualification for .1 The minimum preheating temperature is not
thickness to be less than that used in the qualification test.
Thickness of the Range of approval The maximum interpass temperature is not to be
test piece, t (mm) higher than that used in the qualification test.
30≤t ≥3 mm
3.16.5.9 Post-weld heat treatment
3.16.5.4 Welding position
The heat treatment used in the qualification test
is to be specified in pWPS. Soaking time may be
.1 Approval for a test made in any position is
adjusted as a function of thickness.
restricted to that position.

Section 4

Tubes

4.1 Scope 4.1.4 At the discretion of the Surveyor, modified

testing procedure may be adopted for small
4.1.1 Following requirements make provision for quantities of materials. In such cases, these
copper and copper alloy tubes intended for use may be accepted on the manufacturer's
in heat exchangers, condensers and pressure declared chemical composition and hardness
piping systems. tests or other evidence of satisfactory
properties.
4.1.2 Except for pipes for Class lll pressure
systems (as defined in Pt.4, Ch.2) all pipes and 4.1.5 Pipes for Class lll pressure systems are to
tubes are to be manufactured and tested in be manufactured and tested in accordance with
accordance with the requirements of Ch.1 and 2 the requirements of an acceptable national/
of this Part and the requirements of this Section. international specification. The manufacturer's
test certificate will be acceptable and is to be
4.1.3 Pipes and tubes which comply with provided for each consignment of material.
national/international or proprietary specifica-
ions may be accepted provided that these 4.2 Manufacture
specifications give reasonable equivalence to
the requirements of this Section or are otherwise 4.2.1 Approval of Works, as required by Ch.1,
specifically approved for a specific application for the manufacture of copper and copper alloy
and provided that survey is carried out in tubes is generally not required.
accordance with Ch.1 of this Part.

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4.2.2 Unless otherwise agreed tubes shall be stress relieving heat treatment when subjected
solid drawn. to a cold straightening operation after annealing.

4.3 Quality 4.6 Mechanical tests

4.3.1 Tubes are to have a workmanlike finish 4.6.1 The tubes are to be presented in lots of
and are to be clean and free from such surface 600 tubes or 900 [Kg], whichever is greater.
and internal defects as can be established by Each lot is to contain tubes of the same
the specified tests. dimensions, material grade and in the same
state of heat treatment. From each lot 2 tubes
4.3.2 The tubes are to be supplied in straight are to be selected for testing.
lengths, and the ends are to be cut clean and
square with the axis of the tube. 4.6.2 Following tests are to be carried out on
each tube selected for testing in accordance
4.3.3 The tolerance on wall thickness and with the requirements of Ch.2:
diameter of pipes and tubes are to be in
accordance with an acceptable national/ a) Tensile test;
international standard.
b) Flattening test;
4.4 Chemical composition
c) Drift Expanding test.
4.4.1 The chemical analysis is to comply with
the requirements of Table 4.4.1. Residual 4.6.3 Flattening test is to be carried out until the
elements are not to be present in amounts interior surfaces of the tube meet.
greater than specified in an acceptable
national/international standard. 4.6.4 For the drift-expanding test, the mandrel is
to have an included angle of 45.
4.5 Heat treatment
4.6.5 The results of all mechanical tests are to
4.5.1 All tubes are to be supplied in the comply with the requirements of Table 4.6.1.
annealed condition. Aluminium brass tubes may
additionally be required to be given a suitable

Table 4.4.1 : Chemical composition of tubes 1)

Chemical composition %
Designation
Cu Fe Ni Zn As Al Mn P Pb
Phosphorus
99.90 2) 0.013-
deoxidised non- - - - - - - -
min. 0.050
arsenical copper
Phosphorus
99.20 2) 0.30- 0.013-
deoxidised - - - - - -
min. 0.50 0.050
arsenical copper
0.02- 1.8-
Al-brass 76.0-79.0 - - Remainder - - -
0.06 2.3
Copper-nickel 9.0-
Remainder 1.0-1.8 - - - 0.5-1.0 - -
90/10 11.0
Copper-nickel 30.0-
Remainder 0.4-1.0 - - - 0.5-1.5 - -
70/30 32.0
Notes:

1) Table shows essential alloying elements only

2) Includes silver also.

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Table 4.6.1 : Mechanical properties for acceptance purposes

Designation 0.2% proof Tensile strength 5.65So% Drift

stress [N/mm2] [N/mm2] minimum expansion test
minimum minimum % minimum
Phosphorus deoxidised non-
100 220 35 30
arsenical copper
Phosphorus deoxidised
100 220 35 30
arsenical copper
Al-brass 110 320 35 30
Copper-nickel 90/10 100 270 30 30
Copper-nickel 70/30 120 360 30 30

4.7 Visual examination

Unless otherwise stated the pressure need not
4.7.1 All pipes are to be presented for visual be greater than 7.0 [N/mm2].
examination and verification of dimensions. The
manufacturer is to provide adequate lighting 4.9.2 The test pressure is to be maintained for
conditions to enable an internal and external sufficient time to permit proof and inspection.
examination of the tubes to be carried out. Unless otherwise agreed, the manufacturer's
certificate of satisfactory hydraulic test will be
4.8 Stress cracking test accepted subject to 10 per cent of the tubes
being retested in the presence of the Surveyor.
4.8.1 This test is applicable to aluminium brass If one of the tubes in a batch does not pass the
only. Mercurous Nitrate Test or alternatively at test, it will be rejected, and all other tubes in the
the express agreement between purchaser and batch are to be retested.
manufacturer Ammonia Vapour Cracking Test
are to be carried out on test specimen to prove 4.10 Identification
that the tubes are free from internal stresses.
The tests are to be carried out in accordance 4.10.1 Tubes are to be clearly marked by the
with an acceptable national/international manufacturer in accordance with the
standard. requirements of Ch.1, with at least the following
details:
4.8.2 Should a specimen reveal cracks when
tested, the manufacturing batch shall be a) IR;
rejected. The manufacturer shall be free to
submit the batch to renewed heat treatment b) Manufacturer's name or trade mark;
before presenting it for retesting.
c) Grade of material.
4.9 Hydraulic test
4.10.2 Identification is to be by rubber stamp or
4.9.1 All tubes are to be hydraulically tested by stencil. Hard stamping is not to be used.
the manufacturer to the following pressure:
4.11 Certification
5 x t x Rm 4.11.1 The manufacturer is to provide the
P
D Surveyor with a written statement giving the
where, following particulars for each lot of material
accepted:-
P = Test pressure;
a) Purchaser's name and Order no.;
t = nominal wall thickness; b) Grade of material;
c) Description and dimensions;
D = nominal outside diameter; d) Cast number and chemical composition;
e) Mechanical test results and results of stress
Rm = Tensile strength in accordance with Table cracking tests where applicable.
4.6.1.

End of Chapter

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Chapter 9

Aluminium Alloys

Contents
Section

1 General
2 Wrought Aluminium Alloys
3 Aluminium Alloy Castings
4 Aluminium/Steel Transition Joints

Section 1

General

1.1 Scope 1.1.4 The numerical designation (grade) of

aluminium alloys and the temper designation are
1.1.1 This Chapter specifies the requirements based on those of the Aluminium Association.
for wrought aluminium alloys for structural
applications, aluminium alloy castings and Temper conditions (delivery heat treatment) are
aluminium/steel transition joints intended for use as defined in EN 515 Or ANSI H35.1.
in ship and machinery construction.
1.1.5 When required by the relevant Chapters of
1.1.2 This Chapter is not applicable to the Rules dealing with design and construction,
aluminium alloys for forgings and to the use of structural aluminium alloys, aluminium alloy
aluminium alloys at low temperature for castings and aluminium/steel transition joints are
cryogenic applications. For these products to be manufactured and tested in accordance
suitable alloys which comply with recognized with the appropriate requirements of Ch.1 and 2
standards may be used. and those detailed in this Chapter.

1.1.3 These requirements are applicable to 1.1.6 Consideration may be given to aluminium
wrought aluminium alloy products within a alloys not specified in this chapter and to
thickness range of 3 [mm] and 50 [mm] alternative temper conditions, complying with
inclusive. The application of aluminium alloys recognized national or international standards
products outside this thickness range requires with specifications equivalent to the
prior agreement of IRS. requirements of this chapter.

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Section 2

Wrought Aluminium Alloys

2.1 Scope 2.3 Quality of materials

2.1.1 This Section deals with wrought aluminium 2.3.1 Materials are to be free from surface or
alloys for structural applications including plates, internal defects of such a nature as would be
sections, tubes, bars and rivet bars and rivets. harmful in service.

2.1.2 Wrought aluminium alloys are to have a 2.4 Dimensional tolerances

satisfactory resistance to corrosion in marine
environment. Grades for welded structures are 2.4.1 The dimensional tolerances are to be in
to be weldable, applying one of the welding accordance with Table 2.4.1, Table 2.4.2 and
methods approved by IRS. Table 2.4.3 and are minimum requirements.

2.1.3 The alloy grades 6005A, 6061 of the 6000 2.4.2 Dimensional tolerances other than those
series should not be used in direct contact with given in Table 2.4.1, Table 2.4.2 and Table 2.4.3
sea water unless protected by anodes and/or are to comply with a recognized national or
paint system. international standard.

2.2 Manufacture 2.5 Chemical composition

2.2.1 Aluminium alloys are to be manufactured 2.5.1 Samples for chemical analysis are to be
at Works approved by IRS. Also refer Chapter 1, taken representative of each cast, or the
Section 1, Cl. 1.3.2. equivalent where a continuous melting process
is involved.
2.2.2 The alloys may be cast either in ingot
moulds or by an approved continuous casting 2.5.2 The chemical composition of these
process. Plates are to be formed by rolling and samples is to comply with the requirements of
may be hot or cold finished. Bars and sections Table 2.5.1.
may be formed by rolling, extrusion or drawing.

Table 2.4.1 : Under thicknesses tolerances for rolled products

Thickness tolerances for nominal width [mm]

Nominal thickness [t] w  1500 1500 < w  2000 2000 < w  3500
[mm]
3.0  t < 4.0 0.10 0.15 0.15
4.0  t < 8.0 0.20 0.20 0.25
8.0  t < 12.0 0.25 0.25 0.25
12.0  t < 20.0 0.35 0.40 0.50
20.0  t < 50.0 0.45 0.50 0.65

Table 2.4.2 : Under thicknesses tolerances for extruded open profiles

Thickness tolerances for nominal thicknesses for a diameter of the

circumscribing circle [mm]
Nominal thickness Upto 250 From 250 to 400 Above 400
[mm]
From 3 to 6 0.25 0.35 0.40
From 6 to 50 0.30 0.40 0.45

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Table 2.4.3 : Under thicknesses tolerances for extruded closed profiles

Nominal thickness [mm] Thickness tolerances [mm]

From 3 to 6 0.25
From 6 to 50 0.30

Table 2.5.1 : Chemical composition

Oth- Oth-
Al Si Fe Cu Mn Mg Cr Zn Ti
ers (2) ers (2)
Grade Misc.
Each Total
% % % % % % % % %
% %
0.40-
Remain 0.6- 5.0-
5059 0.45 0.50 0.25 0.25 0.90 0.20 0.05 3) 0.15 4)
der 1.2 6.0
Remain 0.4- 4.0- 0.05-
5083  0.40  0.40  0.10  0.25  0.15  0.05  0.15
der 1.0 4.9 0.25
Remain 0.20- 3.5- 0.05-
5086  0.40  0.50  0.10  0.25  0.15  0.05  0.15
der 0.7 4.5 0.25
4.0-
Remain 0.7-
5383 0.25 0.25 0.20 5.2 0.25 0.40 0.15 0.05 3) 0.15 3)
der 1.0
0.10 
Remain  2.6- Mn +
5754  0.40  0.40  0.50  0.30  0.20  0.15  0.05  0.15
der 0.10 3.6 Cr 
0.60
Remain
0.50 – 4.7 – 0.05 –
5456 der 0.25 0.40 0.10 0.25 0.20 0.05 0.15
1.0 5.5 0.20
0.12 
Remain 0.50- 0.040- Mn +
6005-A  0.35  0.30  0.50  0.30  0.20  0.10  0.05  0.15
der 0.9 0.7 Cr 
0.50
Remain 0.40- 0.15- 0.8- 0.04-
6061  0.7  0.15  0.25  0.15  0.05  0.15
der 0.8 0.40 1.2 0.35
Remain 0.7- 0.40- 0.6-
6082  0.50  0.10  0.25  0.20  0.10  0.05  0.15
der 1.3 1.0 1.2

Notes:

1. Slight variations in the content of some elements, compared with values indicated in this Table may be accepted with IRS's
agreement.
2. Other metallic elements such as Ni, Ga.V are considered as impurities. The regular analysis need not be made for these
elements.
3. Zr: maximum 0.20. The total for other elements does not include Zirconium.
4. Zr: 0.05-0.25. The total for other elements does not include Zirconium.

2.5.3 The manufacturer’s declared analysis will

be accepted subject to occasional checks if 2.6 Heat treatment
required by IRS Surveyor, particularly, product
analysis may be required where the final product 2.6.1 Temper conditions (delivery heat
chemistry is not well represented by the analysis treatment) are defined in Table 2.8.1.
from the cast.
2.7 Test material
2.5.4 When the aluminium alloys are not cast in
the same works in which they are manufactured 2.7.1 All materials in a lot forwarded for
into semi finished products, the works is to give sampling are to be of the same alloy, production
a certificate detailing the chemical composition batch and product form (plates, sections etc.).
and heat number. The materials in one lot are to be of the same

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dimensions and in the same delivery condition. 2.8.3.3 The test specimens are to be cut with
Artificially aged grades are to be from the same the ends perpendicular to the axis of the profile.
furnace batch. The edges of the end may be rounded by filing.

2.7.2 Wherever practicable, the tensile test 2.8.3.4 The length of the specimen is to be in
pieces for rolled and extruded sections are to be accordance with details given in Chapter 2.
of full section of material. Otherwise, the pieces
are to be taken in the range one third to half the 2.8.3.5 Testing is to be carried out at ambient
distance from the edge to center of the temperature and is to consist of expanding the
predominant or thickest part of the section. end of the profile by means of a hardened
conical steel mandrel having an included angle
2.8 Testing and inspection of at least 60.

2.8.1 Testing procedures 2.8.3.6 The sample is considered to be

unacceptable if the sample fails with a clean
The test specimens and procedures are to be in split along the weld line which confirms lack of
accordance with Ch.2. fusion.

2.8.2 Verification of proper fusion of press welds 2.8.4 Requirements of mechanical properties for
for closed profiles. rolled products in different delivery conditions
are given in Table 2.8.1 and are applicable for
The Manufacturer has to demonstrate by thickness within the range 3 [mm] to 50 [mm].
macrosection tests or drift expansion tests of For thickness above 10 [mm], however, lower
closed profiles performed on each batch of mechanical properties may be accepted.
closed profiles that there is no lack of fusion at
the press welds. 2.8.5 Requirements of mechanical properties for
extruded products in different delivery conditions
2.8.3 Drift expansion tests are given in Table 2.8.2 and are applicable for
thickness within the range 3 [mm] to 50 [mm].
2.8.3.1 Every fifth profile is to be sampled after
final heat treatment. 2.8.6 Requirements of mechanical properties
One sample is to be selected from the batches and delivery conditions for extruded closed
of five profiles or less. profiles are given in Table 2.8.3.

Every profile is to be selected if the length 2.8.7 Other delivery conditions with related
exceeds 6 [m]. mechanical properties may be accepted by IRS,
in each particular case.
2.8.3.2 Two samples are to be cut from the front
and back end of each production profile.

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Table 2.8.1 : Mechanical properties for rolled products 3 [mm]  t  50 [mm]

Elongation % minimum 1)
3) 0.2% proof Tensile
Temper Thickness, On gauge On gauge
Grade stress strength
condition [t] length of 50 length of 5 x
[N/mm2] [N/mm2]
[mm] dia

O 3  t  50 mm 125 275-350 16 14

H111 3  t  50 mm 125 275-350 16 14

H112 3  t  50 mm 125 275 12 10

5083

H116 3  t  50 mm 215 305 10 10

H321 3  t  50 mm 215-295 305-385 12 10

O 3  t  50 mm 145 290 - 17

5383
H111 3  t  50 mm 145 290 - 17

H116 3  t  50 mm 220 305 10 10

H321 3  t  50 mm 220 305 10 10
O 3  t  50 mm 160 330 24 24

H111 3  t  50 mm 160 330 24 24

5059 3  t  20 mm 270 370 10 10

H116
20 < t  50 mm 260 360 - 10
3  t  20 mm 270 370 10 10
H321
20 < t  50 mm 260 360 - 10

O 3  t  50 mm 95 240-305 16 14

H111 3  t  50 mm 95 240-305 16 14

3  t  12.5 mm 125 250 8

5086 H112
12.5 < t  50 mm 105 240 9

H116 3  t  50 mm 195 275 10 2) 9

O 3  t  50 mm 80 190-240 18 17
5754
H111 3  t  50 mm 80 190-240 18 17

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Table 2.8.1 : (Contd.)

Elongation % minimum 1)
3) 0.2% proof Tensile
Temper Thickness, On gauge On gauge
Grade stress strength
condition t length of 50 length of 5 x
[N/mm2] [N/mm2]
[mm] dia
3  t  6.3 mm 130-205 290-365 16
O
6.3 < t  50 mm 125-205 285-360 16 14
3  t  30 mm 230 315 10 10
H116 30 < t  40 mm 215 305 10
5456
40 < t  50 mm 200 285 10
3  t  12.5 mm 230-315 315-405 12
H321 12.5 < t  40 mm 215-305 305-385 10
40 < t  50 mm 200-295 285-370 10
Notes:
1) Elongation in 50 mm apply for thicknesses upto and including 12.5 mm and in 5d for thicknesses
over 12.5 mm.
2) 8% for thicknesses upto and including 6.3 mm.
3) The mechanical properties for the O and H111 tempers are the same. However, they are
separated to discourage dual certification as these tempers represent different processing.

Designation Condition
F As fabricated
O Annealed, soft
H1 Strain hardened only
H2 Strain hardened and partially annealed
H3 Strain hardened and thermally stabilized
H321 Strain hardened and stabilized
H11 Strain hardened to specified strength
H12 Strain hardened to specified strength
H13 Strain hardened to specified strength
H111 Less strain hardened than H11 e.g. by straightening or stretching
H112 No controlled strain hardening, but there are mechanical property limits
H116 Treatment against exfoliation corrosion
Cooled from an elevated temperature shaping process and then artificially
T5
aged
T6 Solution heat treated and then artificially aged.

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Table 2.8.2 : Mechanical properties for extruded products 3 [mm]  t  50 mm

Elongation % minimum 1)
0.2% proof Tensile
Temper Thickness, On gauge On gauge
Grade stress strength
condition t length of 50 length of 5 x
[N/mm2] [N/mm2]
[mm] dia

O 3  t  50 mm 110 270-350 14 12

5083 H/111 3  t  50 mm 165 275 12 10

H112 3  t  50 mm 110 270 12 10

O 3  t  50 mm 145 290 17 17
5383 H111 3  t  50 mm 145 290 17 17
H112 3  t  50 mm 190 310 13
5059 H112 3  t  50 mm 200 330 10

O 3  t  50 mm 95 240-315 14 12

5086 H111 3  t  50 mm 145 250 12 10

H112 3  t  50 mm 95 240 12 10

T5 3  t  50 mm 215 260 9 8
6005A
3  t  10 mm 215 260 8 6
T6
10  t  50 mm 200 250 8 6

6061 T6 3  t  50 mm 240 260 10 8

T5 3  t  50 mm 230 270 8 6
6082
3  t  50 mm 250 290 6
T6
3  t  50 mm 260 310 10 8
Notes:

1) The values are applicable for longitudinal and transverse tensile test specimens as well.
2) Elongation in 50 mm applies for thicknesses upto and including 12.5 mm and in 5d for
thicknesses over 12.5 mm.

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Table 2.8.3 : Mechanical properties for extruded closed profiles

(testing transverse to extruding direction)

Grade Temper 0.2% proof stress Tensile strength Elongation % min

condition [N/mm2] [N/mm2] on gauge length
of 5 x dia
6061 T5/T6 205 245 4
6005A T5/T6 215 250 5
6082 T5/T6 240 290 5

2.9 Freedom from defects the relationship between microstructure and

resistance to corrosion, the master
2.9.1 The finished material is to have a good photomicrographs and the results of the
finish and is to be free from internal and surface corrosion tests are to be approved by IRS.
defects prejudicial to the use of the concerned Production practices are not to be changed after
material for the intended application. approval of the reference micrographs.

2.9.2 Slight surface imperfections may be Other test methods may also be accepted at the
removed by smooth grinding or machining as discretion of IRS.
long as the thickness of the material remains
within the tolerances given in 2.4. 2.10.3 For batch acceptance of 5xxx-alloys in
the H116 and H321 tempers, metallographic
2.10 Corrosion testing examination of one sample selected from mid
width at one end of a coil or random sheet or
2.10.1 Rolled 5xxx-alloys of type 5083, 5383, plate is to be carried out. The microstructure of
5059, 5086 and 5456 in the H116 and H321 the sample is to be compared to the reference
tempers intended for use in marine hull photomicrograph of acceptable material in the
construction or in marine applications where presence of the Surveyor. A longitudinal section
frequent direct contact with seawater is perpendicular to the rolled surface is to be
expected, are to be corrosion tested with prepared for metallographic examination under
respect to exfoliation and intergranular corrosion the conditions specified in ASTM B928, Section
resistance. 9.6.1. If the microstructure shows evidence of
continuous grain boundary network of
2.10.2 The manufacturers are to establish the aluminium-magnesium precipitate in excess of
relationship between microstructure and the reference photomicrographs of acceptable
resistance to corrosion when the above alloys material, the batch is either to be rejected or
are approved. A reference photomicrograph tested for exfoliation-corrosion resistance and
taken at 500x under the conditions specified in intergranular corrosion resistance subject to the
ASTM B928, Section 9.4.1, is to be established agreement of the Surveyor. The corrosion tests
for each of the alloy-tempers and relevant are to be in accordance with ASTM G66 and
thickness ranges. The reference photographs G67 or equivalent standards. Acceptance
are to be taken from samples which have criteria are as noted below:
exhibited no evidence of exfoliation corrosion
and a pitting rating of PB or better, when i) The sample is to exhibit no evidence of
subjected to the test described in ASTM G66 exfoliation corrosion
“Standard test method for visual assessment of ii) The pitting rating of the sample is to be
exfoliation, corrosion susceptability of 5xxx PB or better when subjected to ASTM
series aluminium alloys” (ASSET Test). The G66 ASSET test
samples are also to have exhibited resistance to iii) The sample is to exhibit resistance to
intergranular corrosion at a mass loss not intergranular corrosion at a mass loss
greater than 15 [mg/cm2], when subjected to no greater than 15 [mg/cm2] when
tests described in ASTM G67 “Standard test subjected to ASTM G67 NAMLT test.
method for determining the susceptibility to
intergranular corrosion of 5xxx series aluminium If the results from testing satisfy the acceptance
alloys by mass loss after exposure to nitric acid” criteria the batch is accepted, else it is to be
(NAMLT). Upon satisfactory establishment of rejected.

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2.12 Mechanical test specimens
As an alternative to metallographic examination,
each batch may be tested for exfoliation- 2.12.1 Type and location of tensile test
corrosion resistance and intergranular corrosion specimens are to be in accordance with details
resistance, in accordance with ASTM G66 and given in Ch.2.
G67 under the conditions specified in ASTM
B928 or equivalent standards. If this alternative 2.13 Number of test specimens
is used, then the results of the test must satisfy
the acceptance criteria stated above. 2.13.1 Tensile test

2.11 Test materials a) Rolled products

2.11.1 Definition of batches - One tensile test specimen is to be taken

Each batch is made up of products: from each batch of the product. If the
weight of one batch exceeds 2000 [kg],
- of the same alloy grade and from the one extra tensile test specimen is to be
same cast taken from every 2000 [kg] of the
product or fraction thereof, in each
- of the same product form and similar batch.
dimensions (for plates, the same
thickness) - For single plates or for coils weighing
more than 2000 [kg] each, only one
- manufactured by the same process tensile test specimen per plate or coil
shall be taken.
- having been submitted simultaneously
to the same temper condition. b) Extruded products

2.11.2 The test samples are to be taken - For the products with a nominal weight
of less than 1 [kg/m], one tensile test
- at one third of the width from a specimen is to be taken from each 1000
longitudinal edge of rolled products. [kg], or fraction thereof, in each batch.
For nominal weights between 1 and 5
- in the range 1/3 to 1/2 of the distance [kg/m], one tensile test specimen is to
from the edge to the centre of the be taken from each 2000 [kg] or fraction
thickest part of extruded products. hereof, in each batch. If the nominal
weight exceeds 5 [kg/m], one tensile
2.11.3 Test samples are to be taken so that the test specimen is to be taken for each
orientation of test specimens is as follows: 3000 [kg] of the product or fraction
thereof, in each batch.
a) Rolled products
2.13.2 Corrosion tests
Normally, tests in the transverse direction
are required. If the width is insufficient to For rolled plates of grade 5083, 5383, 5059 and
obtain transverse test specimen, or in the 5086 delivered in the tempers H116 or H321,
case of strain hardening alloys, tests in the one sample is to be tested per batch.
longitudinal direction will be permitted.
2.14 Retest procedures
b) Extruded products
2.14.1 When the tensile test from the first piece
The extruded products are tested in selected in accordance with Sec.11 fails to meet
longitudinal direction. the requirements, two further tensile tests may
be made from the same piece. If both of these
2.11.4 After removal of test samples, each test additional tests are satisfactory, this piece and
specimen is to be marked in order that its the remaining pieces from the same batch may
original identity, location and orientation is be accepted.
maintained.

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2.14.2 If one or both the additional tests referred to be reduced by more than 20 per cent. The
to above are unsatisfactory, the piece is to be welding is to be carried out by approved
rejected, but the remaining material from the welders. The weld is to be ground flush with the
same batch may be accepted provided that two surrounding piece surface. Before repair welding
of the remaining pieces in the batch selected in is commenced and after grinding the weld bead,
the same way, are tested with satisfactory suitable non destructive testing may be required
results. If unsatisfactory results are obtained at the discretion of the Surveyor.
from either of these two pieces then the batch of
material is to be rejected. 2.17 Identification

2.14.3 In the event of any material bearing the 2.17.1 The manufacturer is to adopt a system of
Classification Society's brand failing to comply identification which will ensure that all finished
with the test requirements, the brand is to be material in a batch presented for test is of the
unmistakably defaced by the manufacturer. same nominal chemical composition.

2.15 Visual and non-destructive examination 2.17.2 Products are to be clearly marked by the
manufacturer in accordance with the
2.15.1 Surface inspection and verification of requirements of Ch.1. The following details are
dimensions are the responsibility of the to be shown on all materials which have been
manufacturer, and acceptance by the Surveyors accepted:
of material later found to be defective shall not
absolve the manufacturer from this a) Manufacturer's name or trade mark;
responsibility.
b) Grade of alloy;
2.15.2 In general, the non-destructive
examination of materials is not required for c) Identification mark which will enable the full
acceptance purposes. Manufacturers are history of the item to be traced;
expected, however to employ suitable methods
of non-destructive examination for the general d) Abbreviated designation of temper condition
maintenance of quality standards. in accordance with para 2.6;

2.15.3 For applications where the non- e) Personal stamp of the Surveyor responsible
destructive examination of materials is for the final inspection and also IRS’s
considered to be necessary, the extent of this stamp.
examination, together with appropriate
acceptance standards, are to be agreed f) Tempered grades that are corrosion tested
between the purchaser, manufacturer and in accordance with 2.12 are to be marked
Surveyor. “M” after the temper condition, e.g. 5083
H321 M.
2.16 Rectification of defects
2.17.3 When extruded products are bundled
2.16.1 Local surface defects may be removed together or packed in crates for delivery, the
by machining or grinding, provided the thickness marking specified in para 2.17.2 are to be
of the material remains within the tolerances affixed by a securely fastened tag or label.
given in para 2.4. The extent of repairs is to be
agreed upon with the Surveyor, and all repairs 2.18 Certification
are to be carried out under Surveyor's
supervision, unless otherwise arranged. 2.18.1 Each test certificate or shipping
statement is to include the following particulars :
2.16.2 Surface defects which cannot be dealt
with as in 2.12.1 are not allowed to be repaired, a) Purchaser's name and order number;
unless it can be ensured that repair by welding
does not affect the strength and stability of the b) Contract number;
piece for the intended purpose. Any case of
repair by welding is to be specified in detail for c) Address to which material is to be
consideration and approval by the Surveyor. dispatched;
Prior to any such repair welding, the defect is to
be removed by machining or grinding. After d) Description and dimensions;
complete removal of the defect and before
welding the thickness of the piece at no place is e) Specification or grade of alloys;

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f) Identification mark which will enable the full j) Corrosion test results (if any).
history of the item to be traced;
2.18.2 Where the alloy is not produced at the
g) Chemical composition; works at which it is wrought, a certificate is to be
supplied by the Manufacturer of the alloy stating
h) Mechanical test results (Not required on the cast number and chemical composition. The
shipping statement); works at which alloys are produced must be
approved by IRS. Also refer Chapter 1, Section
i) Details of heat treatment, where applicable; 1, Cl. 1.3.2.
and

Section 3

Aluminium Alloy Castings

3.1 Scope 3.2 Manufacture

3.1.1 Provision is made in this section for 3.2.1 Castings are to be manufactured at
aluminium alloy castings intended for use in the foundries approved by IRS.
construction of ships, ships for liquid chemicals
and other marine structures, liquefied gas piping 3.3 Quality of castings
systems where the design temperature is not
lower than minus 165C. These materials should 3.3.1 All castings are to be free from surface or
not be used for piping outside cargo tanks internal defects which would be prejudicial to
except for short lengths of pipes attached to their proper application in service.
cargo tanks in which case fire resisting
insulation should be provided. 3.4 Chemical composition

3.1.2 Castings are to be manufactured and 3.4.1 The chemical composition of a sample
tested in accordance with Ch.1 and Ch.2 and from each cast is to comply with the
also with the requirements of this Section. requirements given in Table 3.4.1. Suitable grain
refining elements may be used at the discretion
3.1.3 As an alternative to 3.1.2, castings which of the Manufacturer. The content of such
comply with National/International and elements is to be reported in ladle analysis.
proprietary specifications may be accepted
provided that these specifications give 3.4.2 Where it is proposed to use alloys not
reasonable equivalence to the requirements of specified in Table 3.4.1 details of chemical
this Section or are approved for a specific composition, heat treatment and mechanical
application. Generally survey and certification properties are to be submitted for approval.
are to be carried out in accordance with the
requirements of Ch.1. 3.4.3 When a cast is wholly prepared from
ingots for which an analysis is already available,
and provided that no significant alloy additions
are made during melting, the ingot maker's
certified analysis can be accepted subject to
occasional checks as required by the Surveyor.

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Table 3.4.1 : Chemical composition for aluminium alloy castings

Grade
Alloy Element %
AlMg3 AlSi12 AlSi10Mg AlSi7 High purity
Copper 0.1 max 0.1 max. 0.1 max. 0.1 max.
Magnesium 2.5 - 4.5 0.1 max. 0.15 - 0.4 0.25 - 0.45
Silicon 0.5 max. 11.0 - 9.0 - 11.0 6.5 - 7.5
13.5
Iron 0.5 max. 0.7 max. 0.6 max. 0.2 max.
Manganese 0.6 max. 0.5 max. 0.6 max. 0.1 max.
Zinc 0.2 max. 0.1 max. 0.1 max. 0.1 max.
Chromium 0.1 max. - - -
Titanium 0.2 max. 0.2 max. 0.2 max. 0.2 max.
Others
each 0.05 max. 0.05 max. 0.05 max. 0.05 max.
Total 0.15 max. 0.15 max. 0.15 max. 0.15 max.
Aluminium Remainder Remainder Remainder Remainder

3.5 Heat treatment [kgs] of fettled castings may be regarded as a

cast.
3.5.1 Castings are to be supplied in the following
conditions: 3.6.2 The test samples are to be separately cast
in moulds made from the same type of material
Grade Al-Mg 3 As manufactured as used for the castings. These moulds should
conform to National Standards.
Grade Al-Si 12 As manufactured
3.6.3 The methods and procedures for the
Grade Al-Si 10 Mg As manufactured or identification of the test specimens, and the
solution heat treated castings they represent, are to be agreed with
and precipitation the Surveyor. The identification marks are to be
hardened maintained during the preparation of test
specimens.
Grade Al-Si 7 Mg Solution heat treated
and precipitation (high 3.6.4 Where castings are supplied in the heat
purity) hardened treated condition, the test samples are to be
heat treated together with the castings which
3.6 Mechanical tests they represent prior to testing.

3.6.1 At least one tensile specimen is to be 3.6.5 The results of all tensile tests are to
tested from each cast, where heat treatment is comply with the appropriate requirements given
involved, for each treatment batch from each in Table 3.6.1 and/or Table 3.6.2.
cast. Where continuous melting is employed 500

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Table 3.6.1 : Minimum mechanical properties for acceptance purpose of sand cast and
investment cast reference test pieces

Alloy Temper (see Note) Tensile strength Elongation %

[N/mm2]
AlMg3 M 150 5
AlSi12 M 150 3
AlSi10Mg M 150 2
AlSi10Mg TF 220 1
AlSi7Mg TF 230 5
Note
M - As cast condition
TF - Solution heat treated and precipitation hardened condition

Table 3.6.2 : Minimum mechanical properties for acceptance purpose of

chill cast reference test pieces

Alloy Temper (see Note) Tensile strength Elongation %

[N/mm2]
AlMg3 M 150 5
AlSi12 M 170 3
AlSi10Mg M 170 3
AlSi10Mg TF 240 1.5
AlSi7Mg TF 250 5
Note
M - As cast condition
TF - Solution heat treated and precipitation hardened condition

3.7 Visual examination Such repair is to be made in accordance with an

approved procedure.
3.7.1 All castings are to be cleaned and
adequately prepared for inspection. 3.9 Pressure testing

3.7.2 The accuracy and verification of 3.9.1 Where required by the relevant
dimensions are the responsibility of the construction rules, castings are to be pressure
manufacturer, unless otherwise agreed. tested before final acceptance. Unless otherwise
agreed, these tests are to be carried out in the
3.7.3 Before acceptance, all castings are to be presence and to the satisfaction of the Surveyor.
presented to the Surveyor for visual
examination. 3.10 Identification

3.8 Rectification of defective castings 3.10.1 The manufacturer is to adopt a system of

identification which will enable all finished
3.8.1 At the discretion of the Surveyor, small castings to be traced to the original cast and the
surface blemishes may be removed by local Surveyor is to be given full facilities for tracing
grinding. the casting when required.

3.8.2 Where appropriate, repair by welding may 3.10.2 All castings which have been tested and
be accepted at the discretion of the Surveyor. inspected with satisfactory results are to be
clearly marked with following details :

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3.11 Certification
a) Identification number, cast number or other
numbers which will enable the full history of 3.11.1 The manufacturer is to provide the
the casting to be traced; Surveyor with a written statement giving the
following particulars for each casting or batch of
b) IR and the abbreviated name of local office castings which have been accepted :
of IRS;
a) Purchaser name and order number;
c) Personal stamp of the surveyor responsible
for the inspection; b) Description of castings and alloy type;

d) Test pressure where applicable; and c) Identification number;

e) Date of final inspection. d) Ingot or Cast analysis;

3.10.3 Where small castings are manufactured e) General details of heat treatment where
in large numbers, modified arrangements for applicable;
identification may be specially agreed with the
Surveyor. f) Results of mechanical tests; and

g) Test pressure, where applicable.

Section 4

Aluminium/Steel Transition Joints

4.1 Scope 4.2.4 Intermediate layers between aluminium

and steel may be used, in which case the
4.1.1 Provision is made in this section for material of any such layer is to be specified by
explosion bonded composite aluminium/steel the manufacturer and will be recorded in the
transition joints used for connecting aluminium approval certificate. Any such intermediate layer
structures to steel plating. is then to be used in all production joints.

4.1.2 Each design is to be separately approved 4.3 Visual and non-destructive examination
by IRS.
4.3.1 Each composite plate is to be subjected to
4.2 Manufacture 100 per cent visual and ultrasonic examination
in accordance with a relevant National/
4.2.1 Transition joints are to be manufactured by International standard to determine the extent of
an approved producer in accordance with an any unbounded areas. The unbounded areas
approved specification which is to include the are unacceptable and any such area and the
maximum temperature allowable at the interface surrounding 25 [mm] area is to be discarded.
during welding.
4.4 Mechanical tests
4.2.2 The aluminium material is to comply with
the requirements of Sec.1 and the steel is to be 4.4.1 Two shear test specimens and two tensile
of an appropriate grade complying with the test specimens are to be taken from each end of
requirements of Ch.3. each composite plate for tests to be made on
bond strength. One shear and one tensile test
4.2.3 Alternative materials which comply with specimen from each end are to be tested at
International, National or proprietary ambient temperature after heating to the
specifications may be accepted provided that maximum allowable interface temperature; the
they give reasonable equivalence to the other two specimens are to be tested without
requirements of 4.2.2 or are approved for a heat treatment.
specific application.

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4.4.2 Shear tests may be made on a specimen
as shown in Fig.4.4.1 or an appropriate
equivalent. Tensile tests may be made across
the interface by welding extension pieces to
each surface or by the ram method shown in
Fig.4.4.2 or by an appropriate alternative
method.

4.4.3 The shear and tensile strengths of all the

test specimens are to comply with the
requirements of the manufacturing specification.

4.4.4 If either the shear or tensile test strength of

the bond is less than the specified minimum but
not less than 70 per cent of the specified
minimum, two additional shear and two tensile
test specimens from each end of the composite
plate are to be tested and, in addition bend tests
as described in 4.4.6 and Table 4.4.1 are to be
conducted.

4.4.5 If either the shear or the tensile strength of

the bond is less than 70 per cent of the specified
minimum the case is to be investigated. After
evaluation of the results of this investigation IRS
will consider the extent of composite plate which
is to be rejected.

4.4.6 Bend tests, when required, are to be made

under the following conditions, as listed in Table
4.4.1 :

a) the aluminium plate is in tension;

b) the steel plate is in tension; and

c) a side bend is applied.

Table 4.4.1 : Bend tests on explosion bonded aluminium / steel transition joints
Type of test Minimum bend, degrees Diameter of former
Aluminium in tension 90 3T
Steel in tension 90 3T
Side bend 90 6T

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4.5 Identification
b) The contract number for which the material
4.5.1 Each acceptable transition strip is to be is intended, if known;
clearly marked with IRS brand IR and the
following particulars : c) Address to which the material is dispatched;

a) Manufacturers name or trade mark; d) Description and dimensions of the material;

b) Identification mark for the grade of e) Specification or grades of both the

aluminium; and aluminium alloy and the steel and any
intermediate layer;
c) Identification mark for the grade of steel.
f) Cast numbers of steel and aluminium
The particulars are to be stamped on the plates;
aluminium surface at one end of the strip.
g) Identification number of the composite plate;
4.6 Certification and

4.6.1 Each test certificate or shipping statement h) Mechanical test results (not required on the
is to include the following particulars : shipping statement).

a) Purchaser's name and order number;

End of Chapter

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Chapter 10

Equipment

Contents
Section

1 Anchors
2 Stud Link Chain Cables
3 Short Link Chain Cables
4 Steel Wire Ropes
5 Offshore Mooring Chains

Section 1

Anchors

1.1 Scope For welded super high holding power (SHHP)

anchors, the base steel grades are to be
1.1.1 The following paragraphs give selected with respect to the material grade
requirements for cast, forged or fabricated steel requirements for Class II in Part 3, Chapter 2
anchor heads, shanks and anchor shackles. 'Materials of Construction' Section 2 'Use of
The requirements given in this section are Steel Grades'.
applicable to the following types of anchors:
1.2.4 The welding consumables are to meet the
a) Ordinary stockless and stocked anchors toughness for the base steel grades in
b) High Holding Power (HHP) anchors, accordance with Part 2, Chapter 11 'Approval of
and Welding Consumables for Use in Ship
c) Super High Holding Power (SHHP) Construction'.
anchors not exceeding 1500 [kg] in
mass. 1.2.5 Fabrication is to be carried out by qualified
welders using approved welding procedure.
1.2 Manufacture
1.2.6 The toughness of the anchor shackles for
1.2.1 Cast steel anchor heads, shanks and SHHP anchors is to meet that for Grade CC3
shackles are to be manufactured and tested in anchor chain given in Section 2. The toughness
accordance with the relevant requirements for of steel castings for SHHP anchors is to be not
castings for welded construction of Ch.4. The less than charpy V-notch energy average of 27 J
steel is to be fine grain treated with aluminium. at 0C.
The toughness of steel castings for SHHP
anchors is to be not less than charpy V-notch 1.2.7 Hardness values of mating parts are to be
energy average of 27 J at 0C. such that the more easily replaceable part wears
faster.
1.2.2 Forged steel anchor heads, shanks,
shackles and anchor crown pins are to be 1.3 Dimensions and tolerances
manufactured in accordance with the
requirements for forgings of weldable quality of 1.3.1 Anchors are to be manufactured as per
Ch.5. approved drawings or as per internationally
recognised designs meeting the tolerances
1.2.3 Plate material and bars used for the specified in such documents. In addition the
manufacture of fabricated parts of steel anchors following dimensional tolerances are also to be
are to comply with the requirements of Ch.3. applied:

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- the clearance either side of the shank within c) For high holding power anchors - a nominal
the shackle jaws is not to be more than 3 mass equal to 1.33 times the actual mass of
[mm] for anchors upto 3000 [kg] mass, 4 the anchor;
[mm] for anchors upto 5000 [kg] mass, 6
[mm] for anchors upto 7000 [kg] mass and d) For super high holding power anchors - a
12 [mm] for larger anchors. nominal mass equal to 2.0 times the actual
mass of the anchor.
- the shackle pin is to be push fit in the eyes
of the shackle, which are to be chamfered 1.4.3 The proof load is to be applied on the arm
on the outside to ensure tightness when the or on the palm at a spot which, measured from
pin is clenched over. The shackle pin to hole the extremity of the bill, is one-third of the
clearance is not to be more than 0.5 [mm] distance between it and the centre of the crown.
for pins upto 57 [mm] and not more than 1
[mm] for pins of larger diameter In the case of the stockless anchors, both arms
are to be tested at the same time, first on one
- the anchor crown pin is to be snug fit within side of the shank, then reversed and tested on
the chamber and long enough to prevent the other.
horizontal movement. The gap is not to be
more than 1% of the chamber length. 1.4.4 Before application of proof test load the
anchors are to be examined to be sure that
- The lateral movement of the shank should castings are reasonably free of surface
not exceed 3 degrees. imperfections of harmful nature.

1.4 Proof test of anchors On completion of the proof load tests the
anchors are to be examined for cracks and other
1.4.1 Anchors of all sizes are to be proof load defects and for anchors made in more than one
tested with the load specified in Table 1.4.1. piece, the anchors are to be examined for free
Anchors inclusive of stock, having a mass of 75 rotation of their heads over the complete angle.
[kgs] or more (56 [kgs] in case of high holding
power anchors) are to be tested at a proving In every test the difference between the gauge
establishment recognized by IRS. lengths (shown in Fig.1.4.4), where one-tenth of
the required load was applied first and where
1.4.2 The proof test load is to be as given in the load has been reduced to one-tenth of the
Table 1.4.1. The mass to be used in the Table is required load from the full load, is not to exceed
to be as follows:- one percent (1%).

a) For stockless anchors - the total mass of the 1.4.5 In addition to the requirements given in
anchor; this Chapter attention must be given to any
relevant statutory requirements of the National
b) For stocked anchors - the mass of the Authority of the country in which the ship is to be
anchor excluding the stock; registered.

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Table 1.4.1 : Proof loads for anchors

Mass of anchor Mass of anchor Mass of anchor

Proof load* [kN] Proof load* [kN] Proof load* [kN]
[kg] [kg] [kg]
(2) (2) (2)
(1) (1) (1)
50 23.2 2000 349.0 7000 804.0
55 25.2 2100 362.0 7200 818.0
60 27.1 2200 376.0 7400 832.0
65 28.9 2300 388.0 7600 845.0
70 30.7 2400 401.0 7800 861.0
75 32.4 2500 414.0 8000 877.0
80 33.9 2600 427.0 8200 892.0
90 36.3 2700 438.0 8400 908.0
100 39.1 2800 450.0 8600 922.0
120 44.3 2900 462.0 8800 936.0
140 49.0 3000 474.0 9000 949.0
160 53.3 3100 484.0 9200 961.0
180 57.4 3200 495.0 9400 975.0
200 61.3 3300 506.0 9600 987.0
225 65.8 3400 517.0 9800 998.0
250 70.4 3500 528.0 10000 1010.0
275 74.9 3600 537.0 10500 1040.0
300 79.5 3700 547.0 11000 1070.0
325 84.1 3800 557.0 11500 1090.0
350 88.8 3900 567.0 12000 1110.0
375 93.4 4000 577.0 12500 1130.0
400 97.9 4100 586.0 13000 1160.0
425 103.0 4200 595.0 13500 1180.0
450 107.0 4300 604.0 14000 1210.0
475 112.0 4400 613.0 14500 1230.0
500 116.0 4500 622.0 15000 1260.0
550 125.0 4600 631.0 15500 1270.0
600 132.0 4700 638.0 16000 1300.0
650 140.0 4800 645.0 16500 1330.0
700 149.0 4900 653.0 17000 1360.0
750 158.0 5000 661.0 17500 1390.0
800 166.0 5100 669.0 18000 1410.0
850 175.0 5200 677.0 18500 1440.0
900 182.0 5300 685.0 19000 1470.0
950 191.0 5400 691.0 19500 1490.0
1000 199.0 5500 699.0 20000 1520.0
1050 208.0 5600 706.0 21000 1570.0
1100 216.0 5700 713.0 22000 1620.0
1150 224.0 5800 721.0 23000 1670.0
1200 231.0 5900 728.0 24000 1720.0
1250 239.0 6000 735.0 25000 1770.0
1300 247.0 6100 740.0 26000 1800.0
1350 255.0 6200 747.0 27000 1850.0
1400 262.0 6300 754.0 28000 1900.0
1450 270.0 6400 760.0 29000 1940.0
1500 278.0 6500 767.0 30000 1990.0
1600 292.0 6600 773.0 31000 2030.0
1700 307.0 6700 779.0 32000 2070.0
1800 321.0 6800 786.0 34000 2160.0
1900 335.0 6900 794.0 36000 2250.0

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Table 1.4.1 : Proof loads for anchors (Contd.)

Mass of anchor Mass of anchor Mass of anchor

Proof load* [kN] Proof load* [kN] Proof load* [kN]
[kg] [kg] [kg]
(2) (2) (2)
(1) (1) (1)
38000 2330.0 42000 2490.0 46000 2650.0
40000 2410.0 44000 2570.0 48000 2730.0
Proof loads for intermediate masses are to be determined by linear interpolation
Notes

Where ordinary anchors have a mass exceeding 48 000 [kg], the proof loads are to be taken as 2.059 (mass of anchor in kg)2/3
[kN].

Where high holding power anchors have a mass exceeding 38 000 [kg], the proof loads are to be taken as 2.452 (actual mass of
anchor in kg)2/3 [kN].

1.5 Inspections and other tests 1.5.2 Drop test is to be carried out by dropping
each anchor component individually from a
1.5.1 Inspection and testing of anchor height of 4 [m] to an iron or steel slab. The iron
components is to be carried out as per the or steel slab should be able to resist the impact.
following: The component under test should not fracture.
a) Cast components are to be tested as per
1.5.3 Hammering test is to be carried on each
Test Programme A fluke and shank, after the drop test, by
hammering the component, hung clear off the
or ground using a non-metallic sling, with a
hammer of not less than 3 [kg] mass, to check
Test Programme B, where the Charpy V notch the soundness.
energy average of the cast material at 0C is not
less than 27J. 1.5.4 Visual inspection is to be carried out of all
accessible surfaces after the proof load test.
b) Forged / fabricated components are to be
tested as per Test Programme B. 1.5.5 General non-destructive examination is to
be carried out, after proof load testing, as per
Test Programme A is to consist of Drop Test, Table 1.5.5.
Hammering Test, Visual Inspection and General
NDE as described below. 1.5.6 Extended non-destructive examination is
to be carried out, after proof load testing, as per
Test Programme B is to consist of Visual Table 1.5.6.
Inspection, general NDE and Extended NDE as
described in 1.5.5 and 1.5.6 below.

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Table 1.5.5 : General NDE for Anchors

Location Method of NDE

SHHP Ordinary / HHP
Feeders of castings DP or MP and UT DP or MP
Risers of castings DP or MP and UT DP or MP
All surfaces of castings DP or MP Not required
Weld repairs DP or MP DP or MP
Forged components Not required Not required
Fabrication welds DP or MP DP or MP
DP : Dye Penetrant Test
MP : Magnetic Particle Test
UT : Ultrasonic Testing

Table 1.5.6 : Extended NDE for ordinary, HHP and SHHP anchors

Location Method of NDE

Feeders of castings DP or MP and UT
Risers of castings DP or MP and UT
All surfaces of castings DP or MP
Random areas of castings UT
Weld repairs DP or MP
Forged components Not required
Fabrication welds DP or MP
DP : Dye Penetrant Test
MP : Magnetic Particle Test
UT : Ultrasonic Testing

1.6 Identification e) Mass of stock (in case of stocked anchors);

1.6.1 All identification marks are to be stamped f) Personal stamp of Surveyor responsible for
on one side of the anchor, on the shank and the inspection.
fluke, at locations reserved solely for this
purpose. g) Manufacturer’s mark

1.6.2 The following details are to be marked on h) Unique cast identification number of shank
all the anchors:- and fluke, if applicable.

a) IR and abbreviated name of local office of 1.6.3 In addition to the markings detailed in
IRS issuing the certificate; 1.6.2, each important part of the anchor is to be
plainly marked with the words 'forged steel' or
b) Number of the certificate; 'cast steel' as appropriate.

c) Month and year of test; 1.7 Painting

d) Mass (also the letters 'HHP/SHHP', when 1.7.1 Anchors are to be painted only on
approved for as high holding power completion of all inspections and tests.
anchor/super high holding power anchor);

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Section 2

Stud Link Chain Cables

2.1 Scope 2.3 Design and tolerances

2.1.1 The following requirements apply to the 2.3.1 The form and proportion of chain cable
materials, design, manufacture and testing of links and shackles are to be in accordance with
stud link anchor chain cables and accessories ISO/1704 (see Figs.2.3.1 to 2.3.6). All
used for ships. dimensions in the figures are shown in multiples
of the nominal diameter d of the common link.
2.1.2 Depending upon the nominal tensile The dimensions in brackets may be chosen for
strength of the chain cable steel used for studless links in outboard end swivel pieces.
manufacture, stud link chain cables are Where designs do not comply with this and
subdivided in to three grades, namely CC1, CC2 where accessories are of welded construction,
and CC3. plans giving full details of the design,
manufacturing process and heat treatment are
2.2 Manufacture to be submitted for approval.

2.2.1 Chain cables and accessories are to be 2.3.2 The following tolerances are applicable to
manufactured at Works approved by IRS for the links with the provision that the plus tolerance
pertinent type of chain cable, size and method of may be up to 5 per cent of the nominal diameter:
manufacture. Also refer Chapter 1, Section 1,
Cl. 1.3.2. a) Nominal diameter Max. minus
Measured at the tolerance
2.2.2 Chain cables are to be preferably Crown (see note)
manufactured by flash butt welding using
Upto 40 [mm] 1 [mm]
material suitable for CC1, CC2 or CC3 grades of
chain cables. Chain cables may also be Over 40 and upto 84 2 [mm]
manufactured by drop forging or casting. [mm]
Over 84 and upto 122 3 [mm]
Accessories such as shackles, swivels and [mm]
swivel shackles are to be forged or cast in steel
of at least grade CC2 material. The welded Over 122 and upto 4 [mm]
construction of these components will be 152 [mm]
specially considered. Over 152 and upto 6 [mm]
184 [mm]
2.2.3 Details of the method of manufacture and Over 184 and upto 7.5 [mm]
the specification of the steel are to be submitted 222 [mm]
for approval.
Note : Two measurements are to be taken
2.2.4 All materials used for the manufacture of
at the same location: one in the plane of the
chain cables and accessories are to be supplied link (see dp in Fig.2.3.7) and one
by manufacturer’s works approved by IRS. Also perpendicular to the plane of the link. The
refer Chapter 1, Section 1, Cl. 1.3.2. However,
cross sectional area at the crown is to be
for Grade CC1 steel bars, approval of material calculated using the average of the
manufacturer is not required. diameters with negative and plus tolerance
For Grade CC3 steel bars, detailed material The cross sectional area at the crown must
specifications including manufacturing not have any negative tolerance. For
procedure, deoxidation practice, specified
diameters of 20 [mm] or greater, the plus
chemical composition, heat treatment and tolerance may be upto 5 per cent of the
mechanical properties are to be submitted. nominal diameter. For diameters less than
20 [mm] the plus tolerance is to be agreed
with IRS at the time of approval;

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Diameter measured at locations other than length from one bar in each batch is to be
the crown is to have no negative tolerance. selected for test purposes.
Plus tolerance may be up to 5 per cent of
the nominal diameter except at the butt weld 2.4.3 In order to evaluate the suitability of the
where it is to be in accordance to bar material the sample selected from each
manufacturer’s specification, which is to be batch is to be tested in a heat treatment
agreed with IRS. For diameters less than condition equivalent to that of the finished chain
20[mm], the plus tolerance is to be agreed cable and accessories. For this purpose only the
with IRS at the time of approval. sample need be heat treated.

a) The maximum allowable tolerance on 2.4.4 For all grades, one tensile test is to be
assembly measured over a length of 5 links taken from each sample selected. Additionally
may equal +2.5 per cent but may not be one set of three Charpy V-notch impact test
negative (measured with the chain under specimens is to be prepared and tested as
tension after proof load test); required in Table 2.4.1.

b) All other dimensions are subject to a 2.4.5 Where the dimensions allow, the test
manufacturing tolerance of  2.5 per cent, specimens are to be taken at approximately
provided that all of the final link parts fit one-third of the radius from the outer surface as
together properly; shown in Fig.2.4.1. For smaller diameters the
test specimens are to be taken as close as
c) Studs must be located in the links centrally possible to these positions.
and at right angles to the sides of the link,
although the studs at each end of any length 2.4.6 The cross-sectional area of the tensile test
may also be located off-centre to facilitate specimen is to be not less than 150 [mm2].
the insertion of the joining shackle. The Alternatively, the tensile test specimen may be a
following tolerances are regarded as being suitable length of bar tested in full cross-section.
inherent in the method of manufacture and
will not be objected to provided the stud fits 2.4.7 The impact test specimens are to be
snugly and its ends lie practically flush notched in the radial direction as shown in
against the inside of the link. Fig.2.4.1.

Maximum off- 10 per cent of the 2.4.8 The results of all the mechanical testing
centre distance 'X' nominal diameter d are to comply with the requirements of Table
Maximum deviation 4 2.4.1.
"" from the 90
position 2.4.9 The average value obtained from one set
of three impact test specimens is to comply with
The tolerances are to be measured in the requirements given in Table 2.4.1. One
accordance with Fig.2.3.7. individual value only may be below the specified
average value provided it is not less than 70% of
2.3.3 The following tolerances are applicable to that value.
accessories :
If the Charpy V-notch impact test requirements
Nominal diameter : + 5 per cent, - 0 per cent are not achieved, a retest of three further
Other diameter :  2.5 per cent. specimens selected from the same sample as
per 1.10.2 of Chapter 1 shall be permissible.
2.4 Material for welded chain cables and Failure to meet the requirements will result in
accessories rejection of the test unit represented unless it
can be clearly attributable to improper simulated
2.4.1 Bar material intended for the manufacture heat treatment.
of welded chain cables is to be in accordance
with the appropriate requirements of Ch.3. If the tensile test requirements are not achieved,
Rimming steel is not acceptable for this a retest of two further specimens selected from
application. the same sample shall be permissible. Failure to
meet the specified requirements in either of the
2.4.2 Bars of the same nominal diameter are to additional tests will result in rejection of the test
be presented for test in batches of 50 tonnes or unit represented unless it can be clearly
fraction thereof from the same cast. A suitable attributable to improper simulated heat
treatment.

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Table 2.4.1 : Mechanical properties of rolled steel bars for acceptance purposes

Yield Impact Tests

Tensile Elongation Reduction
strength Test temp.C Average
Designation strength on 5.65 of area %
[N/mm2] energy J
[N/mm2] So% min. min.
min. min.1
Grade CC1 300 - 490 - 25 - - -
Grade CC2 490 - 690 295 22 - 0 271
Grade CC3 Min. 690 410 17 40 02 60
-20 35

1 The impact test of grade CC2 material may be waived, if the chain is to be supplied in a heat treated
condition as per Table 2.9.1.

2 The impact testing is normally to be carried out at 0C.

Table 2.4.2 : Chemical composition of rolled steel bars

Chemical Composition
Designation C Si Mn P S Al (Total)1
max. max. max. min.
Grade CC1 0.20 0.15 - 0.35 min. 0.40 0.040 0.040 -
Grade CC22 0.24 0.15 - 0.55 max. 1.60 0.035 0.035 0.020
Grade CC3 3 To be specially considered in each case

1 Aluminium may be replaced partly by other grain refining elements.

2 Subject to special consideration, additional alloying elements may be added.

3 To be killed and of fine grain.

Table 2.4.3 : Dimensional tolerance of rolled steel bars

Nominal diameter [mm] Tolerance on diameter [mm] Tolerance on roundness

(dmax - dmin) [mm]
Less than 25 -0 + 1.0 0.6
25 – 35 -0 +1.2 0.8
36 – 50 -0 + 1.6 1.1
51 – 80 -0 + 2.0 1.5
81 – 100 -0 +2.6 1.95
101 – 120 -0 + 3.0 2.25
121 – 160 -0 + 4.0 3.0
161 – 210 -0 + 5.0 4.0

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2.4.10 If failure to pass the tensile test or the

Charpy V-notch impact test is definitely - Results of mechanical tests (where
attributable to improper heat treatment of the applicable)
test sample, a new test sample may be taken
from the same piece and re-heat treated. The - Number of test specimens (where
complete test (both tensile and impact test) is to applicable).
be repeated and the original results obtained
may be disregarded. 2.5 Material for cast chain cables and
accessories
2.4.11 The chemical composition of the steel
bars is to be generally within the limits given in 2.5.1 Manufacture of cast steel chain cables is
Table 2.4.2. generally to be in accordance with Ch.4, as
appropriate.
2.4.12 The tolerances on diameter and
roundness of rolled steel bars are to be within 2.5.2 All castings must be properly heat treated
the limits specified in Table 2.4.3 unless i.e. normalized, normalized and tempered or
otherwise agreed. quenched and tempered, as specified in Table
2.7.1 for the relevant grade of steel.
2.4.13 The minimum markings required for the
steel bars are the manufacturers’ brandmark, 2.6 Material for forged chain cables and
the steel grade and an abbreviated symbol of accessories
the heat. Steel bars having diameters of up to
and including 40 mm and combined into 2.6.1 The procedure for the manufacture of drop
bundles, may be marked on permanently affixed forgings for chain cables will be specially
labels. considered, but is generally to be in accordance
with the appropriate requirements of Ch.5.
2.4.14 Material certification : Bar material for
Grade 2 or Grade 3 is to be certified by IRS. For 2.6.2 The stock material may be supplied in the
each consignment, manufacturers shall forward as rolled condition. Finished forgings are to be
to the Surveyor a certificate containing at least properly heat treated, i.e. normalized,
the following data: normalized and tempered or quenched and
tempered, as specified for the relevant grade of
- Manufacturer’s name and/or purchaser’s steel in Table 2.7.1.
order no.
2.7 Heat treatment of completed chain cables
- Number and dimensions of bars and weight
of consignment 2.7.1 The completed chain cable and
accessories are to be heat treated in
- Steel specification and chain grade accordance with Table 2.7.1, for the appropriate
grade of cable.
- Heat number
2.7.2 In all cases, heat treatment is to be carried
- Manufacturing procedure out prior to the proof, load test, breaking load
test and all mechanical testing.
- Chemical composition

- Details of heat treatment of the test sample

(where applicable)

Table 2.7.1 : Condition of supply of chain cables and accessories

Grade Chain cables Accessories

CC1 As welded or normalized NA
CC2 As welded or normalized 1) Normalized
CC3 Normalized, Normalized and tempered Normalized, normalized and tempered or
or Quenched and tempered Quenched and tempered
1) Grade CC2 chain cables made by forging or casting are to be supplied in the normalized
condition

NA = Not Applicable.

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2.8 Materials and welding of studs 2.9 Testing of completed chain cables

2.8.1 The studs are to be made of steel 2.9.1 Finished chain cables are to be tested in
corresponding to that of the chain cable or from the presence of a Surveyor, at a proving
rolled, cast or forged mild steels. The use of establishment recognized by IRS. For this
other materials, e.g. grey or nodular cast iron is purpose the chain cables must be free from
not permitted. paint and anti-corrosive media. Special attention
would be given to the visual inspection of the
2.8.2 The welding of studs is to be in flash-butt-weld, if present. In addition to the
accordance with an approved procedure subject requirements of this Chapter, attention must be
to following : given to any relevant statutory requirements of
the National Authority of the country in which the
a) The studs being of weldable steel; ship is to be registered.

b) The studs being welded at one end only, i.e. 2.9.2 The design and/or standard breaking loads
opposite to the weldment of the link. The and proof loads of stud link chain cables are
stud ends must fit inside of the link without given in Table 2.9.1 (a). The test loads rounded
appreciable gap; off from the loads in 2.9.1 (a) to be used for
testing and acceptance of chain cables, are
c) The welds, preferably in the horizontal given in Table 2.9.1 (b). Each length of chain is
position, are to be executed by qualified to be subjected to a proof loading test in an
welders using suitable welding approved testing machine and is to withstand
consumables; the load given in Table 2.9.1 for the appropriate
grade and size of cable. On completion of the
d) All the welds are to be completed before the test, each length of cable is to be examined and
final heat treatment of the chain cable; and is to be free from significant defects.

e) The welds are to be free from defects liable Should a proof load test fail, the defective link(s)
to impair the proper use of the chain. is (are) to be replaced, a local heat treatment to
be carried out on the new link(s) and the proof
load test is to be repeated. In addition, an
investigation is to be made to identify the cause
of the failure.

Table 2.9.1(a) : Formulae for proof loads and breaking loads of stud link chain cables

Test Grade CC1 Grade CC2 Grade CC3

Proof load (kN) 0.00686d2 (44 – 0.08d) 0.00981d2 (44 – 0.08d) 0.01373d2 (44 – 0.08d)
Breaking load (kN) 0.00981d2 (44 – 0.08d) 0.01373d2 (44 – 0.08d) 0.01961d2 (44 – 0.08d)
Note d = nominal diameter [mm]

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Table 2.9.1(b) : Test load values for stud link chain cables

Grade CC1 Grade CC2 Grade CC3

Chain cable Proof load Breaking Proof load Breaking Proof load Breaking
diameter load load load

(mm) (kN) (kN) (kN) (kN) (kN) (kN)

1 2 3 4 5 6 7
11 36 51 51 72 72 102
12.5 46 66 66 92 92 132
14 58 82 82 116 116 165
16 76 107 107 150 150 216
17.5 89 127 127 179 179 256
19 105 150 150 211 211 301
20.5 123 175 175 244 244 349
22 140 200 200 280 280 401
24 167 237 237 332 332 476
26 194 278 278 389 389 556
28 225 321 321 449 449 642

30 257 368 368 514 514 735

32 291 417 417 583 583 833
34 328 468 468 655 655 937
36 366 523 523 732 732 1050
38 406 581 581 812 812 1160

40 448 640 640 896 896 1280

42 492 703 703 981 981 1400
44 583 769 769 1080 1080 1540
46 585 837 837 1170 1170 1680
48 635 908 908 1270 1270 1810

50 686 981 981 1370 1370 1960

52 739 1060 1060 1480 1480 2110
54 794 1140 1140 1590 1590 2270
56 851 1220 1220 1710 1710 2430
58 909 1290 1290 1810 1810 2600

60 969 1380 1380 1940 1940 2770

62 1030 1470 1470 2060 2060 2940
64 1100 1560 1560 2190 2190 3130
66 1160 1660 1660 2310 2310 3300
68 1230 1750 1750 2450 2450 3500

70 1290 1840 1840 2580 2580 3690

73 1390 1990 1990 2790 2790 3990
76 1500 2150 2150 3010 3010 4300
78 1580 2260 2260 3160 3160 4500
81 1690 2410 2410 3380 3380 4820

84 1800 2580 2580 3610 3610 5160

87 1920 2750 2750 3850 3850 5500
90 2050 2920 2920 4090 4090 5840
92 2130 3040 3040 4260 4260 6080
95 2260 3230 3230 4510 4510 6440

97 2340 3340 3340 4680 4680 6690

100 2470 3530 3530 4940 4940 7060

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Table 2.9.1(b) : Test load values for stud link chain cables

Grade CC1 Grade CC2 Grade CC3

Chain cable Proof load Breaking Proof load Breaking Proof load Breaking
diameter load load load

(mm) (kN) (kN) (kN) (kN) (kN) (kN)

1 2 3 4 5 6 7
102 2560 3660 3660 5120 5120 7320
105 2700 3850 3850 5390 5390 7700
107 2790 3980 3980 5570 5570 7960

111 2970 4250 4250 5940 5940 8480

114 3110 4440 4440 6230 6230 8890
117 3260 4650 4650 6510 6510 9300
120 3400 4850 4850 6810 6810 9720
122 3500 5000 5000 7000 7000 9990

124 3600 5140 5140 7200 7200 10280

127 3750 5350 5350 7490 7490 10710
130 3900 5570 5570 7800 7800 11140
132 4000 5720 5720 8000 8000 11420
137 4260 6080 6080 8510 8510 12160

142 4520 6450 6450 9030 9030 12910

147 4790 6840 6840 9560 9560 13660
152 5050 7220 7220 10100 10100 14430
157 5320 7600 7600 10640 10640 15200
162 5590 7990 7990 11170 11170 15970

Table 2.9.2 : Number of mechanical test specimens for finished chain cables and accessories

Grade Manufacturing Condition of Number of test specimens

method supply 1) Tensile test Charpy V-notch impact test
for base metal Base metal Weldment
Flash-butt welded AW NR NR NR
CC1
N
Flash-butt welded AW 1 3 3
-------------------- -------------------- -------------------- --------------------
CC2 N NR NR NR
Forged or Cast N 1 3 2) NA
Flash-butt welded N
NT 1 3 3
QT
CC3
Forged or Cast N
NT 1 3 NA
QT

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1) AW = As Welded, N = Normalized, NT = Normalized and Tempered,

QT = Quenched and Tempered

2) For chain cables, Charpy V-notch impact test is not required.

NR = Not required
NA = Not applicable

Table 2.9.3 : Mechanical properties of finished chain cables and accessories

Grade Yield Tensile Elongation Reduction Charpy V-notch impact test

strength strength on 5.65 of area % Test Absorbed energy, in
[N/mm2] [N/mm2] So % min. tempera- Joules min.
min. min. min. ture, in C Base Weldment
metal
CC1 NR NR NR NR NR NR NR
CC2 295 490 – 690 22 NR 0 27 27
CC3 410 690 min. 17 40 0 1) 60 50
-20 35 27
1) Testing is normally to be carried out at 0C.
NR = Not required.

2.9.3 Sample lengths comprising of at least cast chain cables where the batch size is less
three links are to be taken from every four than four lengths, the sampling frequency is to
lengths or fraction of chain cables and tested at be by heat treatment charge. Mechanical tests
the breaking loads given in Table 2.9.1. The are to be carried out in the presence of the
breaking load is to be maintained for a minimum Surveyor. The test specimens and their location
of 30 seconds. The links concerned are to be are to be according to 2.4.5 to 2.4.7 and
made in a single manufacturing cycle together Fig.2.4.1. Testing and re-testing are to be
with the chain cable and must be welded and carried out as given in 2.4.9.
heat treated together with it. Only after this
these may be separated from the chain cable in 2.9.7 An additional link (or where the links are
the presence of the Surveyor. small, several links) for mechanical test
specimen removal is to be provided in a length
2.9.4 Where a breaking load test specimen fails, of chain cable not containing the specimen for
a further specimen is to be cut from the same the breaking test. The specimen link must be
length of cable and subjected to test. If this re- manufactured and heat treated together with the
test fails, the length of cable from which it was length of chain cable.
taken is to be rejected. When this test is also
representative of other lengths, each of the 2.10 Accessories for chain cables
remaining lengths in the batch is to be
individually tested and is to meet the 2.10.1 End and joining shackles, attachment
requirements of the breaking load test. links, adapter pieces, swivels and other fittings
are to be subjected to the proof and breaking
2.9.5 For large diameter cables where the loads appropriate to the grade and size of cable
required breaking load is greater than the for which they are intended in accordance with
capacity of the testing machines, special the requirements of Table 2.9.1.
consideration will be given to acceptance of
other alternative testing procedure. 2.10.2 The breaking load is to be applied to at
least one item out of every 25 (one in 50 for
2.9.6 Mechanical test specimens required in lugless shackles). The items need not
Table 2.9.2 are to be taken from every four necessarily be representative of each heat of
lengths in accordance with 2.9.7. For forged or steel or individual purchase order. Enlarged

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links and end links need not be tested provided
that they are manufactured and heat treated 2.10.4 Unless otherwise specified, the forging or
together with the chain cable. The tested item is casting must at least comply with the
to be destroyed and not used as part of an outfit, mechanical properties given in Table 2.9.3,
in general. However, the accessories, which when properly heat treated. For test sampling,
have been successfully tested at the prescribed forgings or castings of similar dimensions
breaking load appropriate to the chain, may be originating from the same heat treatment charge
used in service at the discretion of IRS where and the same heat of steel are to be combined
the accessories are manufactured with the into one test unit. From each test unit, one
following: tensile test specimen and the Charpy V-notch
impact test specimens are to be taken in
a) material having higher strength accordance with Table 2.9.2. Mechanical tests
characteristics than those specified for the are to be carried out in the presence of the
part in question (e.g. grade 3 material for Surveyor. Location of test specimens and test
accessories for grade 2 chain). procedure are to be as given in 2.4.5 to 2.4.7
and Fig.2.4.1. Testing / re-testing is to be carried
b) or alternatively, same grade material as the out as per 2.4.9. Enlarged links and end links
chain but with increased dimensions and it need not be tested provided they are
is verified by procedure tests that such manufactured and heat treated together with the
accessories are so designed that the chain cable.
breaking strength is not less than 1.4 times
the prescribed breaking load of the chain for 2.11 Identification
which they are intended.
2.11.1 All lengths of cables and accessories are
2.10.3 The breaking load test may be waived if – to be stamped with the following identification
marks:-
a) The breaking load has been demonstrated
on the occasion of the approval testing of a) IR and the abbreviated name of the local
parts of the same design, and office of IRS issuing the certificate;
b) Number of certificate;
b) The mechanical properties of each c) Date of test;
manufacturing batch are approved, and d) Proof load and grade of chain;
e) Personal stamp of the Surveyor responsible
c) The parts are subjected to suitable non- for inspection.
destructive testing.

Section 3

Short Link Chain Cables

3.1 General the requirements stated in this Chapter,

attention is to be given to any relevant statutory
3.1.1 Details regarding the form and proportions requirements of the National Authority of the
of short link chain cable, materials, method of country in which the ship is to be registered.
manufacture and testing are to be submitted for
special consideration by IRS. 3.2.2 For chain of diameter less than 12.5 [mm],
other than steering chains, the manufacturer's
3.1.2 In general the short link chain cables are tests will be accepted.
to comply with the grades L(3) and M(4) of ISO
1834. 3.2.3 After completion of all manufacturing
processes, including heat treatment and
3.2 Testing and inspection of chain cables galvanising, the whole of the chain is to be
subjected to the appropriate proof load specified
3.2.1 All chain cable of 12.5 [mm] diameter and in Table 3.2.1.
above, and all steering chains irrespective of
diameter are to be tested at a proving
establishment recognised by IRS. In addition to

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3.2.4 The whole of the chain is to be inspected into account in determining the total elongation
after the proof load test and is to be free from (See 3.2.7).
significant defects.
3.2.6 The breaking load is to comply with the
3.2.5 At least one sample, consisting of seven or appropriate requirements of Table 3.2.1.
more links, is to be selected by the Surveyor
from each 200 [m] or less of chain for breaking 3.2.7 The total elongation of the breaking load
load tests. Two additional links may be required sample at fracture, expressed as a percentage
for engagement in the jaws of the testing of the original inside length of the sample after
machine. These extra links are not to be taken proof loading, is to be not less than 20 per cent.

Table 3.2.1 : Mechanical test requirements for short link chain cables

Grade L(3) Grade M(4)

Chain diameter
Breaking load Breaking load
[mm] Proof load [kN] Proof load [kN]
min. [kN] min. [kN]
5 - - 7.9 15.8
6 9 18 - -
6.3 - - 12.5 25
7.1 - - 15.9 31.8
8 16 32 20.2 40.4
9 - - 25.5 51
10 25 50 31.5 63
11.2 - - 39.5 79
12 35.5 71 - -
12.5 - - 49.1 98.2
14 - - 63 126
16 - - 81 162
18 - - 102 204
20 - - 126 252
22.4 - - 158 316
25 - - 197 394
28 - - 247 494
32 - - 322 644
36 - - 408 816
40 - - 503 1006
45 - - 637 1274

Section 4

Steel Wire Ropes

4.1 General Alternative type of wire ropes will be specially

considered on the basis of an equivalent
4.1.1 Steel wire ropes are to be manufactured at breaking load and the suitability of the
Works approved by IRS. Also refer Chapter 1, construction for the purpose intended.
Section 1, Cl. 1.3.2.
4.1.3 It is recommended that the wire ropes
4.1.2 The wire ropes are to be of six strand type intended for stream wires, towlines and mooring
with minimum of 16 wires in each strand. In lines be of fiber core construction and wire ropes
addition to complying with the requirements of for towlines and mooring lines used in
this Chapter, the details regarding form of association with mooring winches be of wire
construction and minimum breaking strength are rope core.
to be in accordance with IS: 2266-1989.

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4.2 Materials
4.2.4 Torsion and zinc coating tests are to be
4.2.1 The wire used in the manufacture of the carried out on wire samples taken from a
rope is to be drawn from steel made in suitable length of the completed rope. After
accordance with the requirements of Ch.3. unstranding and straightening, six wires are to
be subjected to both a torsion test and a wrap
Table 4.2.1 : Torsion test - Speed of testing test for adhesion of coating. Additionally, tests to
determine the uniformity of the zinc coating are
Diameter of Maximum speed of to be carried out.
coated wire [mm] testing twists per minute
< 1.5 90 4.2.5 As an alternative to test specimens taken
 1.5 < 3.0 60 as detailed in 4.2.4, tests may be carried out on
 3.0 < 4.0 30 the wire before the rope is stranded.

4.2.2 The tensile strength is generally to be 4.2.6 For the torsion test, the length of the
within the ranges 1420 to 1570 [N/mm2]; 1570 to sample is to be such as to allow a length
1770 [N/mm2] or 1770 to 1960 [N/mm2]. between the grips of 100 times the wire
diameter or 300 [mm], whichever is less. The
4.2.3 The wire is to be galvanized by a hot dip or wire is to be twisted by causing one or both of
electrolytic process to give a uniform coating the vices to be revolved until fracture occurs.
which may be any of the following grades:- The speed of testing is not to exceed, for a
length equal to 100 times the diameter, that
Grade 1 : heavy coating, drawn after given in Table 4.2.1 (a tensile load not
galvanizing; exceeding 2 per cent of the breaking load of the
wire may be applied to keep the wire stretched).
Grade 2 : heavy coating, finally The wire is to withstand, without fracture on a
galvanized; length of 100 times the diameter of wire, the
number of complete twists given in Table 4.2.2.
Grade 3 : light coating, drawn after
galvanizing.

Table 4.2.2 : Torsion test - Minimum number of twists

Minimum number of twists
Diameter of
Grade 2 Grade 1 or 3
coated wire
Tested before Tested after Tested before Tested after
[mm]
stranding stranding stranding stranding
< 1.3 15 13 27 24
 1.3 < 2.3 15 13 26 23
 2.3 < 3.0 14 12 23 20
 3.0 < 4.0 12 10 21 18

4.3 Zinc coating tests

4.3.1 The mass per unit area of the zinc coating

is to be determined in accordance with a
recognised standard and is to comply with the
minimum values given in Table 4.3.1.

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Table 4.3.1 : Zinc coating

Zinc coating [grams/m2]

Diameter of coated wire [mm]
Grade 1 or 2 Grade 3
 0.40 < 0.50 75 40
 0.50 < 0.6 90 50
 0.6 < 0.8 110 60
 0.8 < 1.0 130 70
 1.0 < 1.2 150 80
 1.2 < 1.5 165 90
 1.5 < 1.9 180 100
 1.9 < 2.5 205 110
 2.5 < 3.2 230 125
 3.2 < 4.0 250 135

4.3.2 The uniformity of the zinc coating is to be diameter of the mandrel and that of the wire is to
determined by a dip test carried out in be as in Table 4.3.2. After wrapping on the
accordance with the requirements of a appropriate mandrel the zinc coating is to have
recognized standard. neither flaked nor cracked to such an extent that
any zinc can be removed by rubbing with bare
4.3.3 The adhesion of the coating is to be tested fingers.
by wrapping the wire round a cylindrical mandrel
for 10 complete turns. The ratio between the

Table 4.3.2 : Wrap test for adhesion of zinc coating

Coating Diameter coated wire [mm] Max. ratio of mandrel to wire diameter
Grade 1 and 2 < 1.5 4
 1.5 6
Grade 3 < 1.5 2
 1.5 3

4.4 Test on completed ropes 4.4.2 The actual breaking load is not to be less
than that given in the appropriate approved
4.4.1 The breaking load is to be determined by standard.
testing to destruction a sample cut from the
completed rope. This sample is to be of 4.5 Identification
sufficient length to provide a clear test length of
at least 36 times the rope diameter between the 4.5.1 All completed ropes are to be identified
grips. with attached labels detailing the rope type,
diameter and length.

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Section 5

Offshore Mooring Chains

5.1 Scope mechanical tests including fracture mechanics

tests.
5.1.1 Following requirements apply to the
materials, design, manufacture and testing of 5.3.2 Manufacturers are to submit for review and
offshore mooring chain and accessories approval the sequence of all operations from
intended to be used for application such as: receiving inspection of raw materials to the
mooring of mobile offshore drilling units, shipment of finished products along with details
mooring of floating production units, mooring of of the following manufacturing processes:
offshore loading systems and mooring of gravity
based structures during fabrication. a) bar heating and bending including the
method, temperatures, temperature control
5.1.2 Mooring equipment covered by these and recording;
requirements are common stud and studless
links, connecting common links (splice links), b) flash welding including current, force, time
enlarged links, end links, detachable connecting and dimensional variables as well as control
links (shackles), end shackles, subsea and recording of parameters, maintenance
connectors, swivels and swivel shackles. procedure and programme for welding
machine;
5.1.3 Studless link chain is normally to be
deployed only once, being intended for long- c) flash removal including method and
term permanent mooring systems with pre- inspection;
determined design life.
d) stud insertion method for stud link chain;
5.2 Chain grades
e) heat treatment including furnace types,
5.2.1 Depending on the nominal tensile strength means of specifying, controlling and
of the steels used for manufacture, chains are recording of temperature and chain speed
subdivided into five grades, namely R3, R3S, and allowable limits, quenching bath and
R4, R4S and R5. agitation, cooling method after exit;

5.2.2 Manufacturers propriety specifications for f) proof and break loading including
R4S and R5 may vary subject to design method/machinery, means of horizontal
conditions and acceptance of IRS. support (if applicable), method of
measurement and recording;
5.2.3 Each Grade is to be individually approved.
Approval for a higher grade does not constitute g) non-destructive examination procedures;
approval of a lower grade. If it is demonstrated
to the satisfaction of the IRS that the higher and h) the manufacturer’s surface quality
lower grades are produced to the same requirement of mooring components;
manufacturing procedure using the same
chemistry and heat treatment, consideration will i) the manufacturer’s procedure for removing
be given to qualification of a lower grade by a and replacing defective links without heat
higher. The parameters applied during treatment of the entire chain.
qualification are then, not to be modified during
production.
5.3.3 For initial approval CTOD (Crack Tip
5.3 Approval of chain manufacturers Opening Displacement) tests are to be carried
out on the particular mooring grade of material.
5.3.1 Offshore mooring chain are to be CTOD tests are to be conducted in accordance
manufactured only by works approved by IRS. with a recognized standard such as BS 7448
Also refer Chapter 1, Section 1, Cl. 1.3.2. For Part 1 and BS EN ISO 15653:2010. The CTOD
this purpose approval tests are to be carried out, test piece is to be a standard 2 x 1 single edge
the scope of which is to include proof and notched bend piece, test location as shown in
breaking load tests, measurements and Fig.5.3.1. The notch of the CTOD specimen is to
be located as close to the surface as

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practicable. The minimum cross section of the testing, i.e, a total of six CTOD specimens. The
test piece is to be 50 x 25 [mm] for chain tests are to be taken at minus 20C and the
diameter less than 120 [mm] and 80 x 40 [mm] lowest CTOD of each set of 3 specimens is to
for diameter 120 [mm] and above. CTOD meet the minimum values indicated below in
specimens are to be taken from both the side of Table 5.3.3:
the link containing the weld and from the
opposite side. Three links are to be selected for

Table 5.3.3 Minimum CTOD test values for chain type

Chain R3 [mm] R3S [mm] R4 [mm] R4S and R5 [mm]
Type
BM WM BM WM BM WM BM WM
Stud link 0.20 0.10 0.22 0.11 0.24 0.12 0.26 0.13
Studless 0.20 0.14 0.22 0.15 0.24 0.16 0.26 0.17
Note : BM : Base metal WM : Welded metal

Fig. 5.3.1 : Location of CTOD test specimens for Chain

5.3.4 Calibration of furnaces is to be verified by through the furnaces at representative

measurement and recording of a calibration test travel speed.
piece with dimensions equivalent to the
maximum size of link manufactured. The (c) One thermocouple is to be attached
manufacturer is to submit a procedure for to the surface of the straight part and
furnace temperature surveys which is to include one thermocouple is to be imbedded in
the following requirements: a drilled hole located at the mid
thickness position of the straight part of
(a) The temperature uniformity of the calibration block. The time-
furnaces is to be surveyed whenever temperature curves are to show that the
approval of manufacturer is requested temperatures throughout the cross
and at least annually during normal section and the soaking times are within
operating conditions. specified limits as given in the heat
treatment procedure.
(b) Furnaces are to be checked by
conveying a monitoring link 5.3.5 For R4S and R5 chain and accessories,
instrumented with two thermocouples prior to approval, the manufacturer is to have
undertaken experimental tests or have relevant

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supporting data to develop the chain and
accessory material. The tests and data may For Grade R4, R4S and R5 chain the steel is to
include: fatigue tests, hot ductility tests (no contain a minimum of 0.20 per cent
internal flaws are to develop whilst bending in molybdenum.
the link forming temperature range), welding
parameter research, heat treatment study, strain 5.5.3 A heat treatment sensitivity study
age resistance, temper embrittlement study, simulating chain production conditions is to be
stress corrosion cracking (SCC) data and applied in order to verify mechanical properties
hydrogen embrittlement (HE) study, using slow and establish limits for temperature and time
strain test pieces in hydrated environments. combinations. All test details and results are to
Reports indicating the results of experimental be submitted to IRS.
tests are to be submitted.
5.5.4 The bar manufacturer is to provide
5.4 Approval of quality system at chain and evidence that the manufacturing process
accessory manufacturers produces material that is resistant to strain
ageing, temper embrittlement and for R3S, R4,
5.4.1 Chain and accessory manufacturers are to R4S and R5, hydrogen embrittlement. All test
have a documented and effective quality system details and results are to be submitted to IRS.
approved by IRS. The provision of such a quality
system is required in addition to, and not in lieu 5.6 Approval of forge shops and foundries -
of, the witnessing of tests by a Surveyor as accessories
specified in 5.7 to 5.14.
5.6.1 Forge shops and foundries intending to
5.5 Approval of steel mills - rolled bar supply finished or semi-finished accessories are
to be approved by IRS. A description of
5.5.1 Bar material intended for chain and manufacturing processes and process controls
accessories are to be manufactured only by is to be submitted to IRS. The scope of approval
works approved by IRS. The approval is limited is to be approved by IRS. The approval is to be
to a nominated supplier of bar material. If a limited to a nominated supplier of forged or cast
chain manufacturer wishes to use material from material. If an accessory manufacturer wishes to
a number of suppliers, separate approval tests use material from a number of suppliers, a
must be carried out for each supplier. Also refer separate approval must be carried out for each
Chapter 1, Section 1, Cl. 1.3.2. supplier.

Approval will be given only after successful 5.6.2 Approval will be given only after successful
testing of the completed chain. Each Grade is to testing of the completed accessory. Approval for
be individually approved. Approval for a higher a higher grade does not constitute approval of a
grade does not constitute approval of a lower lower grade. If it is demonstrated to the
grade. If it is demonstrated to the satisfaction of satisfaction of IRS that the higher and lower
IRS that the higher and lower grades are grades are produced to the same manufacturing
produced to the same manufacturing procedure procedure using the same steel specification,
using the same chemistry and heat treatment, supplier and heat treatment, consideration will
consideration will be given to qualification of a be given to qualification of a lower grade by a
lower grade by a higher. The parameters higher. The approval will normally be limited to
applied during qualification are not to be the type of accessory and the designated
modified during production. The approval will mooring grade of material upto the maximum
normally be limited upto the maximum diameter diameter or thickness equal to that of the
equal to that of the chain diameter tested. The completed accessory used for qualification.
rolling reduction ratio is to be recorded and is to unless otherwise agreed by IRS. However, for
be at least 5:1 for R3, R3S, R4, R4S and R5. the different accessories that have the same
The rolling reduction ratio used in production geometry, the tests for initial approval are to be
can be higher, but should not be lower than that carried out on the one having the lowest
qualified. reduction ratio. Qualification of accessory pins to
maximum diameters is also required. Individual
5.5.2 The bar manufacturer is to submit a accessories of complex geometries will be
specification of the chemical composition of the specially considered.
bar material, which must be approved by IRS
and by the chain manufacturer. The bar maker 5.6.3 For forgings – Forgings are to have
is to confirm by analysis and testing that the wrought microstructure and the minimum
specification is met. reduction ratio is to be 3:1. The forging reduction

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ratio, used in the qualification tests, from cast after tempering shall be appropriate to avoid
ingot / slab to forged component is to be temper embrittlement). All test details and
recorded. The forging reduction ratio used in results are to be submitted to IRS.
production can be higher, but should not be
lower than that qualified. The degree of 5.6.6 For initial approval CTOD tests are to be
upsetting during qualification is to be recorded carried out on the particular mooring grade of
and maintained during production. Heat cycling material. Three CTOD tests are to be tested in
during forging and reheating is to be monitored accordance with a recognized standard such as
by the manufacturer and recorded in the forging BS 7448 Part 1 and BS EN ISO 15653:2010.
documentation. The manufacturer is to have a For rectangular accessories, the CTOD test
maintenance procedure and schedule for dies piece is to be a standard 2 x 1 single edge
and tooling which is to be submitted to IRS. notched bend specimen of thickness equal to
full thickness of material to be tested. Subsized
5.6.4 The forge shop or foundry is to submit a specimens may be used, subject to approval by
specification of chemical composition of the IRS. For circular geometries, the minimum cross
forged or cast material, which must be approved section of the test piece is to be 50 x 25 [mm] for
by IRS. For Grade R4, R4S and R5 chain the accessory diameters less than 120 [mm], and 80
steel should contain a minimum of 0.20 per cent x 40 [mm] for diameters 120 [mm] and above.
molybdenum. The notch of the CTOD specimen is to be
located as close to the surface as practicable.
5.6.5 Forges and foundries are to provide The tests are to be taken at minus 20C and the
evidence that the manufacturing process results submitted for review. The minimum
produces material that is resistant to strain values of each set of three specimens are to at
ageing, temper embrittlement and for R4S and least meet the requirements as indicated in
R5 grades, hydrogen embrittlement. A heat Table 5.6.6 (same as that of the studless chain
treatment sensitivity study simulating accessory material shown in Table 5.3.3).
production conditions shall be applied in order to
verify mechanical properties and establish limits
for temperature and time combinations. (Cooling

Table 5.6.6 : CTOD Test Values for Accessories

Grade of R3 [mm] R3S [mm] R4 [mm] R4S & R5 [mm]

Accessory
CTOD 0.20 0.22 0.24 0.26

The geometry of accessories can vary. Figure flow. Figure 5.6.6 (b) shows two possible
5.6.6 shows the CTOD location for circular and sampling positions for CTOD test specimens
rectangular cross sections such as those of the with notch orientation for rectangular type
D-shackle and accessories fabricated from accessories.
rectangular sections. The orientation of the
specimen is to consider the direction of the grain

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Figure 5.6.6 : Location of CTOD test specimens: a) Circular type accessory and b) rectangular
type accessory, B corresponds to the thickness of material, the grain flow is considered in the
longitudinal direction X

5.6.7 Calibration of furnaces shall be verified by 5.7 Rolled steel bars

measurement and recording of a calibration test
piece with dimensions equivalent to the 5.7.1 Steel manufacture
maximum size of link manufactured.
Thermocouples are to be placed both on the 5.7.1.1 The steels are to be manufactured by
surface and in a drilled hole located to the mid basic oxygen, electric furnace or such other
thickness position of the calibration block. The process as may be specially approved. All steels
furnace dimensions are to be such as to allow are to be killed and fine grain treated. The
the whole furnace charge to be uniformly heated austenitic grain size for R3, R3S and R4 is to
to the necessary temperature. Temperature be 6 or finer in accordance with ASTM E112 or
uniformity surveys of heat treatment furnaces for equivalent grain size index in accordance to ISO
forged and cast components are to be carried 643. Measurements for circular sections are to
out according to API Spec 6A/ISO 10423 Annex be taken at 1/3 radius.
M or ASTM A991. The initial survey is to be
carried out with maximum charge (load) in the 5.7.1.2 Steel for bars intended for R4S and R5
furnace. Subsequent surveys are to be carried chain is to be vacuum degassed. The austenitic
out annually and may be carried out with no grain size is to be 6 or finer in accordance with
furnace charge. ASTM E112 or equivalent grain size index in
accordance to ISO 643. Measurements for
The quench bath maximum temperature and the circular sections are to be taken at 1/3 radius.
maximum heat treatment transfer times from
furnace to quench are to be established and 5.7.1.3 For R4S and R5 the following
documented. During production the established information is to be supplied by the bar
quenching parameters are to be followed and manufacturer to the mooring chain manufacturer
records are to be maintained of bath and the results included in the chain
temperatures and transfer times. documentation:

5.6.8 For R4S and R5 refer to additional a) Each heat is to be examined for non-metallic
requirements in 5.3.5. inclusions. The level of micro inclusions is to be
quantified and assessed in accordance with
national/ international standards; to be sure

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inclusion levels are acceptable for the final b) A slow strain rate < 0.0003 per second is to
product. be used during the entire test, until fracture
occurs. (This is approx. 10 minutes for a 20
b) A sample from each heat is to be macro mm diameter specimen).
etched according to ASTM E381 or equivalent to
be sure there is no injurious segregation or c) Tensile strength, elongation and reduction
porosity. of area are to be reported. The requirement
for the test is:
c) Hardenability data, according to ASTM A255,
or equivalent, is to be supplied with each heat. Z1
 0.85
5.7.2 Chemical composition Z2

For acceptance tests, the chemical composition where,

of ladle samples of each heat is to be
determined by the bar manufacturer and is to Z1 = Reduction of area without baking
comply with the approved specification (see
5.5.2). Z2 = Reduction of area after baking

5.7.3 Mechanical tests d) If the requirement of Z1/Z2  0.85 is not

achieved, the bar material may be subjected
.1 Bars of the same nominal diameter are to a hydrogen degassing treatment after
to be presented for test in batches of 50 tonnes agreement with the Surveyor(s). New tests
or fraction thereof from the same heat. Test are to be performed after degassing.
specimens are to be taken from material heat
treated in the same manner as intended for the .3 For all grades, one tensile and three
finished chain. Charpy V-notch specimens are to be taken from
each sample selected. The test specimens are
.2 Each heat of Grade R3S, R4, R4S and to be taken at approximately one-third radius
R5 is to be tested for hydrogen embrittlement. In below the surface, as shown in Sec. 2, Fig.2.4.1.
case of continuous casting, test samples The results of all tests are to be in accordance
representing both the beginning and the end of with the appropriate requirements of Table
the charge are to be taken. In case of ingot 5.7.1.
casting, test samples representing two different
ingots are to be taken. .4 If the tensile test requirements are not
achieved, a retest of two further specimens
a) Two tensile test specimens are to be taken selected from the same sample will be
from the central region of bar material which permissible.
has been subjected to the heat treatment Failure to meet the specified requirements of
cycle intended to be used in production. either or both additional tests will result in
The specimens are to preferably have a rejection of the batch represented unless it can
diameter of 20 mm, alternatively 14 mm. be clearly attributable to improper simulation of
One specimen is to be tested within max. 3 the heat treatment.
hours (1 1/2 hours for 14 mm diameter
specimen) after machining. Where this is .5 If the impact test requirements are not
not possible, the specimen is to be cooled to achieved, a retest of three further specimens
-60C immediately after machining and kept selected from the same sample will be
at that temperature for a period of maximum permissible. The results are to be added to
5 days. those previously obtained to form a new
average. The new average is to comply with the
The second specimen is to be tested after requirements. No more than two individual
baking at 250C for 4 hours (2 hours for 14 results are to be lower than the required
mm diameter specimen). average and no more than one result is to be
below 70 per cent of the specified average
value.

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Failure to meet the requirements will result in IRS and to the acceptance criteria required..
rejection of the batch represented. Where the The bars are to be free of pipe, cracks and
failure can be clearly attributable to improper flakes. If the end length of the delivered
simulation of the heat treatment, new tests may bars is not subjected to UT then it is to be
be permitted at the discretion of the Surveyor. agreed between the bar supplier and the
chain manufacturer of what length of bar is
5.7.4 Dimensional tolerances to be removed from the ends. The details
are to be documented in the approval of
The diameter and roundness are to be within the each bar supplier. Phased array UT
tolerances specified in Sec. 2, Table 2.4.3, procedures may be applied, subject to
unless otherwise agreed. approval by IRS.

5.7.5 Non-destructive examination and repair d) 100 percent of the bar material is to be
examined by magnetic particle (MT) or eddy
a) Non-destructive examination is to be current (ET) or Magnetic Leakage Flux
performed in accordance with recognized Testing (MLFT) methods. The bars are to
standards such as those given below or be free of injurious surface imperfections
equivalent: such as seams, laps and rolled-in mill scale.
Provided that their depth is not greater than
i. Magnetic Particle Testing (MT) of 1 per cent of the bar diameter, longitudinal
Bars – ASTM E1444 and ISO 9934 discontinuities may be removed by grinding
ii. Magnetic Leakage Flux Testing and blending to a smooth contour.
(MLFT) – JIS Z2319
iii. Eddy Current Testing (ET) of bars – All bars supplied in a machined (peeled)
ISO 15549 condition are to be 100% visually inspected.
10% inspection with magnetic particle
Non-destructive examination procedures, testing (MT) or eddy current testing (ET) or
together with rejection / acceptance criteria Magnetic Leakage Flux Testing (MLFT), for
are to be submitted to IRS. longitudinal imperfections may be undertake
at the discretion of the Surveyor. The
b) Manufacturers are to prepare written maximum depth of peeling is to be agreed
procedures for NDE. NDE personnel are to and documented in the approval of each
be qualified and certified according to ISO supplier.
9712, ACCP or equivalent. Personnel
qualification to an employer or responsible e) The frequency of NDE may be reduced at
agency based qualification scheme as SNT- the discretion of the Surveyor provided it is
TC-1A may be accepted if the employer's verified by statistical means that the
written practice is reviewed and found required quality is consistently achieved.
acceptable and the Level III is ASNT Level
III, ISO 9712 Level III or ACCP Professional f) Weld repair of bars is not permitted.
Level III and certified in the applicable
method. NDE operators are to be qualified 5.7.6 Marking
to at least level II.
Each bar is to be stamped with the steel grade
c) The manufacturer is to ensure that 100 designation and the charge number (or a code
percent of bar material intended for either indicating the charge number) on one of the end
chain or fittings is subjected to ultrasonic surfaces. Other marking methods may be
examination at an appropriate stage of the accepted subject to agreement.
manufacture to procedures approved by

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Table 5.7.1 : Mechanical properties of offshore mooring chain and accessories

Yield Tensile Reduc- Charpy V-notch impact test

stress strength Elonga- tion of Average
Test Average
Grade [N/mm2] [N/mm2] tion % area % energy
temp. C energy J
min. min. min. min. flash weld
(Note 2) min.
(Note 1) (Note 1) (Note 3) J min.
0 60 50
R3 410 690 17 50
-20 40 30
0 65 53
R3S 490 770 15 50
-20 45 33
R4 580 860 12 50 -20 50 36
R4S
700 960 12 50 -20 56 40
(Note 4)
R5
760 1000 12 50 -20 58 42
(Note 4)

Notes:

1 Aim value of yield to tensile ratio: 0.92 max.

2 At the option of IRS the impact test of Grade R3 and R3S may be carried out at either 0C or
minus 20C.

3 Reduction of area of cast steel is to be for Grades R3 and R3S: min. 40%, for R4, R4S and R5 :
min. 35% (see 5.9.4).

4 Aim maximum hardness for R4S is HB330 and R5, HB340.

5.8 Forged steel Measurements for circular sections are to be

taken at 1/3 radius. Measurements for non-
5.8.1 Manufacture circular sections are to be taken at 1/4t.

5.8.1.1 Forged steels used for the manufacture 5.8.1.3 For steel intended for R4S and R5
of accessories are to be in compliance with accessories the following information is to be
approved specifications and the submitted test supplied by the steel manufacturer to the
reports approved by IRS. Steel is to be mooring accessory manufacturer and the results
manufactured by basic oxygen, electric furnace included in the accessory documentation:
or such other process as may be specially
approved. All steel is to be killed and fine grain a) Each heat is to be examined for non-metallic
treated. The austenitic grain size for R3, R3S inclusions. The level of micro inclusions is to be
and R4 is to be 6 or finer in accordance with quantified and assessed in accordance with the
ASTM E112 or equivalent grain size index in national / international standards; to be sure
accordance to ISO 643. Measurements for inclusion levels are acceptable for the final
circular sections are to be taken at 1/3 radius. product.
Measurements for non-circular sections are to
be taken at 1/4t. b) A sample from each heat is to be
macroetched according to ASTM E381 or
5.8.1.2 Steel for forgings intended for R4S and equivalent, to be sure there is no injurious
R5 chain is to be vacuum degassed. The segregation or porosity.
austenitic grain size is to be 6 or finer in
accordance with ASTM E112 or equivalent grain c) Hardenability data, according to ASTM A255
size index in accordance to ISO 643. or equivalent, is to be supplied with each heat.

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5.8.2 Chemical composition 5.8.5.2.4 A slow strain rate < 0,0003 s-1 is to be
used during the entire test, until fracture occurs
For acceptance tests, the chemical composition (This is approximately 10 minutes for the 20
of ladle samples of each heat is to be [mm] diameter specimen). Tensile strength,
determined by the bar manufacturer and is to elongation and reduction of area are to be
comply with the approved specification (see reported.
5.5.2).
5.8.5.2.5 The acceptance requirement for the
5.8.3 Heat treatment test is as follows:

Finished forgings are to be properly heat treated Z1/ Z2 ≥ 0.85

in compliance with specifications approved by
IRS. Where:

5.8.4 Mechanical properties Z1 = Reduction of area without baking

Z2 = Reduction of area after baking
The forgings are to comply with the mechanical
properties given in Table 5.7.1, when properly If the requirement Z1/Z2 ≥ 0.85 is not achieved,
heat treated. the bar material may be subjected to a hydrogen
degassing treatment after agreement with IRS.
5.8.5 Mechanical tests New tests are to be performed after degassing.

5.8.5.1 For test sampling, forgings of similar 5.8.6 Non-destructive examination and repair
dimensions (diameters do not differ by more
than 25 mm) originating from the same heat 5.8.6.1 Non-destructive examination is to be
treatment charge and the same heat of steel are performed in accordance with recognized
to be combined into one test unit. From each standards such as those indicated below, or
test unit one tensile and three impact test equivalent. The non-destructive examination
specimens are to be taken and tested. For the procedures, together with rejection / acceptance
location of the test specimens see Sec. 2, criteria are to be submitted to IRS.
Fig.2.4.1.
(a) Magnetic particle testing (MT) of forgings: -
5.8.5.2 Each heat of Grade R3S, R4, R4S and EN 10228-1, ASTM A275, using wet continuous
R5 is to be tested for hydrogen embrittlement. In magnetization technique
case of continuous casting, test samples
representing both the beginning and the end of (b) Ultrasonic testing (UT) of forgings: - EN
the charge is to be taken. In case of ingot 10228-3, ASTM A388, ISO 13588
casting, test samples representing two different
ingots are to be taken. 5.8.6.2 Manufacturers are to prepare written
procedures for NDE. NDE personnel are to be
5.8.5.2.1 Two (2) tensile test specimens are to qualified and certified according to ISO 9712,
be taken from the central region of forged ACCP or equivalent. Personnel qualification to
material which has been subjected to the heat an employer or responsible agency based
treatment cycle intended to be used in qualification scheme as SNT-TC-1A may be
production. A specimen with a diameter of 20 accepted if the employer's written practice is
[mm] is preferred (consideration will be given to reviewed and found acceptable and the Level III
a diameter of 14 [mm]). is ASNT Level III, ISO 9712 Level III or ACCP
Professional Level III and certified in the
5.8.5.2.2 One of the specimens is to be tested applicable method. NDE operators are to be
within a maximum of 3 hours after machining qualified to at least level II.
(for a 14 [mm] diameter specimen, the time limit
is 1½ hours). Where this is not possible, the 5.8.6.3 The forgings are to be subjected to 100
specimen is to be immediately cooled to -60°C percent ultrasonic examination at an appropriate
after machining and kept at that temperature for stage of manufacture and in compliance with the
a maximum period of 5 days. standard approved by IRS.

5.8.5.2.3 The second specimen is to be tested 5.8.6.4 Defects on non-machined surfaces may
after baking at 250°C for 4 hours, alternatively 2 be removed by grinding to a depth of 5% of the
hours for 14 [mm] diameter specimen. nominal diameter. Grinding is not permitted on

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machined surfaces, except for slight inspection 5.9.2 Chemical composition

grinding on plane surfaces to a maximum depth
of 0.8 [mm] in order to investigate spurious For acceptance tests, the chemical composition
indications. Welding repairs are not permitted. of ladle samples of each heat is to be
determined by the bar manufacturer and is to
5.8.7 Marking comply with the approved specification (see
5.5.2).
Marking is to be similar to that specified in 5.7.6.
5.9.3 Heat treatment
5.9 Cast steel
All castings are to be properly heat treated in
5.9.1 Manufacture compliance with specifications approved by IRS.

5.9.1.1 Cast steels used for the manufacture of 5.9.4 Mechanical properties
accessories are to be in compliance with
approved specifications and the submitted test The castings are to comply with the mechanical
reports approved by IRS. Steel is to be properties given in Table 5.7.1. The requirement
manufactured by basic oxygen, electric furnace for reduction of area is, however, reduced to 40
or such other process as may be specially per cent for grades R3 and R3S and 35 per cent
approved. All steel is to be killed and fine grain for grade R4, R4S and R5.
treated. The austenitic grain size for R3, R3S
and R4 is to be 6 or finer in accordance with 5.9.5 Mechanical tests
ASTM E112 or equivalent grain size index in
accordance to ISO 643. Measurements for For test sampling, castings of similar dimensions
circular sections are to be taken at 1/3 radius. originating from the same heat treatment charge
Measurements for non-circular sections are to and the same heat of steel are to be combined
be taken at 1/4t. into one test unit. From each test unit one
tensile and three impact test specimens are to
5.9.1.2 Steel for castings intended for R4S and be taken and tested. For the location of the test
R5 accessories is to be vacuum degassed. The specimens see Sec. 2, Fig.2.4.1.
austenitic grain size is to be 6 or finer in
accordance with ASTM E112 or equivalent grain 5.9.6 Non-destructive Examination and Repair
size index in accordance to ISO 643.
Measurements for circular sections are to be 5.9.6.1 Non-destructive examination is to be
taken at 1/3 radius. Measurements for non- performed in accordance with recognized
circular sections are to be taken at 1/4t. standards, such as those indicated below, or
equivalent. The non-destructive examination
5.9.1.3 For steel intended for R4S and R5 procedures, together with rejection / acceptance
accessories the following information is to be criteria are to be submitted to IRS.
obtained and the results included in the
accessory documentation: (a) Magnetic particle testing (MT) of castings: -
ASTM E709, using wet continuous
a) Each heat is to be examined for non-metallic magnetisation technique
inclusions. The level of micro inclusions is to be
quantified and assessed in accordance with the (b) Ultrasonic testing (UT) of castings: - ASTM
national/international standards; to be sure A609, ISO 13588
inclusion levels are acceptable for the final
product. 5.9.6.2 Manufacturers are to prepare written
procedures for NDE. NDE personnel are to be
b) A sample from each heat is to be macro qualified and certified according to ISO 9712,
etched according to ASTM E381 or equivalent to ACCP or equivalent. Personnel qualification to
be sure there is no injurious segregation or an employer or responsible agency based
porosity. qualification scheme as SNT-TC-1A may be
accepted if the employer's written practice is
c) Hardenability data, according to ASTM A255, reviewed and found acceptable and the Level III
or equivalent is to be supplied with each heat. is ASNT Level III, ISO 9712 Level III or ACCP
Professional Level III and certified in the
applicable method. NDE operators are to be
qualified to at least level II.

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5.9.6.3 The castings are to be subjected to 100 5.10 Materials for studs
percent ultrasonic examination in compliance
with the standard approved by IRS. 5.10.1 The studs intended for stud link chain
cable are to be made of steel corresponding to
5.9.6.4 Defects on non-machined surfaces may that of the chain or in compliance with
be removed by grinding to a depth of 5% of the specifications approved by IRS. In general, the
nominal diameter. Grinding is not permitted on carbon content is not to exceed 0.25 per cent if
machined surfaces, except for slight inspection the studs are to be welded in place.
grinding on plane surfaces to a maximum depth
of 0.8 [mm] in order to investigate spurious 5.11 Design and Manufacture
indications.
5.11.1 Plans with design calculations, giving
5.9.6.5 Where the repair entails removal of more detailed design of chain and accessories made
than 5% of the diameter or thickness, the by or supplied through the chain manufacturer
defective area is to be repaired by welding. The are to be submitted for approval. Typical
excavations are to be suitably shaped to allow designs are given in ISO 1704 (see Sec. 2,
good access for welding. The resulting grooves Fig.2.3.1 to 2.3.6). For studless chain the shape
are to be subsequently ground smooth and and proportions are to comply with the
complete elimination of the defective material is requirements of this section. Other studless
to be verified by NDE. proportions are to be specially approved. It
should be considered that new or non-standard
5.9.6.6 Weld repairs are classified as major or designs of chain, shackles or fittings, may
minor. A weld repair is considered major when require a fatigue analysis and possible
the depth of the groove prepared for welding performance, fatigue or corrosion fatigue testing.
exceeds 25% of the diameter/thickness or 25
[mm], whichever is smaller. All other weld 5.11.2 In addition for stud link chain, plans
repairs are considered minor. showing the detailed design of the stud are to be
submitted for information. The stud is to give an
5.9.6.7 Major weld repairs require approval impression in the chain link which is sufficiently
before the repair is commenced. Proposals for deep to secure the position of the stud, but the
major repairs are to be accompanied by combined effect of shape and depth of the
sketches or photographs showing the extent and impression is to be such as not to cause any
positions of the repairs. A grain refining heat harmful notch effect or stress concentration in
treatment is to be given to the whole casting the chain link.
prior to major repairs. A post weld heat
treatment or repeat of original heat treatment of 5.11.3 Machining of Kenter shackles is to result
castings is to be carried out. in fillet radius of minimum 3 per cent of nominal
diameter.
5.9.6.8 Minor and major weld repairs are to be
recorded on sketches or photographs showing 5.12 Chain cable manufacturing process
the extent and positions of the repairs.
5.12.1 General
5.9.6.9 All weld repairs are to be done by
qualified welders using qualified procedures. Offshore mooring chains are to be manufactured
Welders are to be qualified according to ISO in continuous lengths by flash butt welding and
9606, ASME IX, ASTM A488 or equivalent. are to be heat treated in a continuous furnace;
Procedures are to be qualified according to ISO batch heat treatment is not permitted. The use
15614, ASME IX, ASTM A488 or equivalent with of joining shackles to replace defective links is
the following additional requirements: Charpy V subject to the written approval of the end
notch impact tests with notch locations in weld purchaser in terms of the number and type
metal, fusion line and heat affected zone + 2 permitted, except in special circumstances
[mm] and + 5 [mm] from fusion line, where short lengths of chain are delivered, such
respectively. Test results are to meet the as chafing chain (Ref. 5.15). The use of
requirements specified for the parent metal. connecting common links is restricted to 3 links
in each 100 m of chain.
5.9.7 Marking

Marking is to be similar to that specified in 5.7.6.

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5.12.2 Manufacturing process records tempering is to be appropriate to avoid

temper embrittlement.
Records of bar heating, flash welding and heat
treatment are to be made available for c) Temperature and time or temperature and
inspection by the Surveyor. chain speed are to be controlled and
continuously recorded.
5.12.3 Bar heating
d) Grain determination is to be made for the
a) Bars for links are to be heated by electric final product. The austenitic grain size for
resistance, induction or in a furnace. R3, R3S, R4, R4S and R5 is to be 6 or finer
in accordance with ASTM E112 or
b) For electric resistance heating or induction equivalent grain size index in accordance to
heating, the heating phase is to be ISO 643. Measurements for circular sections
controlled by an optical heat sensor. The are to be taken at surface, 1/3 radius and
controller is to be checked at least once centre for the base material, HAZ and weld.
every 8 hours and the records are to be
maintained.
5.12.6 Mechanical properties
c) For furnace heating, the heat is to be
controlled and the temperature continuously The mechanical properties of finished chain and
recorded using thermocouples in close accessories are to be in accordance with Table
proximity to the bars. The controls are to be 5.7.1. For the location of test specimens see
checked at least once every 8 hours and the Sec. 2, Fig.2.4.1.
records are to be maintained.
5.12.7 Proof and breaking test loads
5.12.4 Flash welding
Chains and accessories are to withstand the
The following welding parameters are to be proof and break test loads given in Table 5.12.1.
controlled during welding of each link:
5.12.8 Freedom from defects
a) Platen motion;
All chains are to have a workmanlike finish
b) Current as a function of time; consistent with the method of manufacture and
be free from defects. Each link is to be
c) Hydraulic pressure. examined in accordance with 5.15.5 using
approved procedures.
The controls are to be checked at least every 4
hours and records are to be maintained. 5.12.9 Dimensions and dimensional tolerances

5.12.5 Heat treatment The form and proportion of links and

accessories are to be in accordance with the
a) Chain is to be austenitized, above the upper approved design. The tolerances given in Sec.
transformation temperature, at a combina- 2, Cl. 2.3 are applicable, in general.
tion of temperature and time within the limits
established. In addition, the tolerances for stud link and
studless common links are to be measured in
b) When applicable, chain is to be tempered at accordance with Fig.5.12.9a) and b).
a combination of temperature and time
within the limits established. Cooling after

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Table 5.12.1 : Formulae for proof and break test loads, weight and length over 5 links

Grade Type Proof load [kN] Break load [kN]

Grade R3 Stud Link 0.0148 d2 (44 – 0.08d) 0.0223 d2 (44 – 0.08d)
Grade R3S Stud Link 0.0180 d2 (44 – 0.08d) 0.0249 d2 (44 – 0.08d)
Grade R4 Stud Link 0.0216 d2 (44 – 0.08d) 0.0274 d2 (44 – 0.08d)
Grade R4S Stud Link 0.0240 d2 (44 – 0.08d) 0.0304 d2 (44 – 0.08d)
Grade R5 Stud Link 0.0251 d2 (44 – 0.08d) 0.0320 d2 (44 – 0.08d)
Grade R3 Studless 0.0148 d2 (44 – 0.08d) 0.0223 d2 (44 – 0.08d)
Grade R3S Studless 0.0174 d2 (44 – 0.08d) 0.0249 d2 (44 – 0.08d)
Grade R4 Studless 0.0192 d2 (44 – 0.08d) 0.0274 d2 (44 – 0.08d)
Grade R4S Studless 0.0213 d2 (44 – 0.08d) 0.0304 d2 (44 – 0.08d)
Grade R5 Studless 0.0223 d2 (44 – 0.08d) 0.0320 d2 (44 – 0.08d)
Chain Weight [kg/m] Stud link = 0.0219 d2
Chain Weight [kg/m] Studless chain weight calculations for each design are to be submitted
Pitch Length : Five link measure
Minimum 22d
Maximum 22.55d

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a) Stud Link – The internal link radii (R) and external radii should be uniform

Designation 1) Description Nominal Minus Tolerance Plus Tolerance

Dimension of the
Link
a Link length 6d 0.15d 0.15d
b Link half length a*/2 0.1d 0.1d
c Link width 3.6d 0.09d 0.09d
e Stud angular 0 degrees 4 degrees 4 degrees
misalignment
R Inner radius 0.65d 0 ----

Notes : 1 Dimension designation is shown in above figure

d = Nominal diameter of chain, (Refer Fig.2.3.1) a* = Actual link length

Fig.5.12.9a) : Stud Link common link, proportions dimensions and tolerances

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b) Studless – The internal link radii (R) and external radii should be uniform.

Designation 1) Description Nominal Minus Tolerance Plus Tolerance

Dimension of the
Link
a Link length 6d 0.15d 0.15d
b Link width 3.35d 0.09d 0.09d
R Inner radius 0.60d 0 ----

Notes : 1 Dimension designation is shown in above figure

d = Nominal diameter of chain
2 Other dimension ratios are subject to special approval.

Fig.5.12.9b) : Stud less common link, proportions dimensions and tolerances

5.12.10 Welding of studs e) Welding of studs at both ends is not

permitted unless specially approved.
a) A welded stud may be accepted for grade
R3 and R3S chains. Welding of studs in f) The welds are to be made by qualified
grade R4 chain is not permitted unless welders using an approved procedure and
specially approved. low-hydrogen approved consumables.

b) Where studs are welded into the links, the g) The size of the fillet weld is, as a minimum,
welding is to be completed before the chain to be as per API Specification 2F.
is heat treated.
h) The welds are to be of good quality and free
c) The stud ends must be a good fit inside the from defects such as cracks, lack of fusion,
link and the weld is to be confined to the gross porosity and undercuts exceeding 1
stud end opposite to the flash butt weld. The mm.
full periphery of the stud end is to be welded
unless otherwise approved. i) All stud welds are to be visually examined.
At least 10 per cent of all stud welds within

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each length of chain are to be examined by he may not witness all proof load tests. The
dye penetrant or magnetic particles after Surveyor is to satisfy himself that the testing
proof load testing. If cracks or lack of fusion machines are calibrated and maintained in a
are found, all stud welds in that length are to satisfactory condition.
be examined.
c) Prior to inspection chains are to be free from
5.12.11 Connecting common links (splice links) scale, paint or other coating and are to have
a suitably prepared surface as per the
.1 Single links to substitute for test links or applied NDE testing standard. The chains
defective links without the necessity for are to be sand- or shot blast to meet this
re-heat treatment of the whole length requirement.
are to be made in accordance with an
approved procedure. Separate 5.13.2 Proof and break load tests
approvals are required for each grade of
chain and the tests are to be made on a) The entire length of chain is to withstand
the maximum size of chain for which the proof load specified in Table 5.12.1
approval is sought. without fracture and without crack in the
flash weld. The load applied is not to
.2 Manufacture and heat treatment of exceed the proof load by more than 10
connecting common link is not to affect per cent when stretching the chain.
the properties of the adjoining links. The Where plastic straining is used to set
temperature reached by these links is studs, the applied load is not to be
nowhere to exceed 250C. greater than that qualified in approval
tests.
.3 Each link is to be subjected to the
appropriate proof load and non- b) A break-test specimen consisting of at
destructive examination as detailed in least 3 links is to be either taken from
Table 5.12.1 and 5.13.5 respectively. A the chain or produced at the same time
second link is to be made identical to and in the same manner as the chain.
the connecting common link; the link is The test frequency is to be based on
to be tested and inspected as per 5.13.4 tests at sampling intervals according to
and 5.14.5. Table 5.13.1 provided that every cast is
represented. Each specimen is to be
.4 Each connecting common link is to be capable of withstanding the break load
marked either on the stud for stud link specified without fracture and without
chain, or on the outer straight length on crack in the flash weld. It will be
the side opposite the flash butt weld for considered acceptable if the specimen
studless chain. This marking is to be in is loaded to the specified value and
accordance with 5.13.7 plus a unique maintained at that load for 30 seconds.
number for the link. The adjoining links
are also to be marked on the studs or c) For chain diameters over 100 [mm],
straight length as above. alternative break-test proposals to the
above break-test will be considered
5.13 Testing and inspection of finished chain whereby a one link specimen is used.
Alternatives are to be approved by IRS.
5.13.1 General Every heat is to be represented, the test
frequency is to be in accordance with
a) This section applies to but is not limited to Table 5.13.1 and it is to be
finished chain cable such as common stud demonstrated and proven that the
and studless links, end links, enlarged end alternative test represents an equivalent
links and connecting common links (splice load application to the three link test.
links).
d) If the loading capacity of the testing
b) All chains are to be subjected to proof load machine is insufficient, an alternative
tests, sample break load tests and sample load testing machine is to be used that
mechanical tests after final heat treatment in does have sufficient capacity (e.g. two
the presence of Surveyor. Where the loading machines in parallel) provided
manufacturer has a procedure to record the testing and calibration procedure are
proof loads and the Surveyor is satisfied agreed with IRS.
with the adequacy of the recording system,

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Table 5.13.1 : Frequency of break and mechanical tests

Nominal chain diameter (mm) Maximum sampling interval (m)

Min - 48 91
49 - 60 110
61 - 73 131
74 - 85 152
86 - 98 175
99 - 111 198
112 - 124 222
125 - 137 250
138 - 149 274
150 - 162 297
163 - 175 322
176 – 186 346
187 – 198 370
199 - 210 395
211 – 222 420

5.13.3 Dimensions and dimensional tolerances weld. Three impact specimens are to be
taken across the flash weld with the notch
After proof load testing, measurements are to be centered in the middle. Three impact
taken on at least 5 per cent of the links in specimens are to be taken across the
accordance with 5.12.9. unwelded side and three impact specimens
are to be taken from the bend region.
The entire chain is to be checked for the length,
five links at a time. By the five link check the first b) The test frequency is to be based on tests at
five links are to be measured. In the next set of sampling intervals according to Table 5.13.1
five links, at least two links from the previous provided that every cast is represented.
five links set are to be included. This procedure Mechanical properties are to be as specified
is to be followed for the entire chain length. The in Table 5.7.1.
measurements are to be taken preferably while
the chain is loaded to 5 - 10 per cent of the c) The frequency of impact testing in the bend
minimum proof load. The tolerances for the 5 may be reduced at the discretion of the
link measurements are indicated in Table Surveyor provided it is verified by statistical
5.12.1, any deviations from the 5 link tolerances means that the required toughness is
are to be agreed by the client and IRS. The links consistently achieved.
held in the end blocks may be excluded from
this measurement. d) Hardness tests are to be carried out on
finished chain. The frequency and locations
Chain dimensions are to be recorded and the are to be agreed with IRS. The recorded
information retained on file. values are for information only and used as
an additional check to verify that the heat
5.13.4 Mechanical tests treatment process has been stable during
the chain production.
a) Links of samples detached from finished,
heat treated chain are to be sectioned for 5.13.5 Non-destructive examination after proof
determination of mechanical properties. A load testing
test unit is to consist of one tensile and nine
impact specimens. The tensile specimen is a) All surfaces of every link are to be visually
to be taken in the side opposite the flash examined. Burrs, irregularities and rough

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edges are to be contour ground. Links are to d) Ultrasonic testing is to be employed to

be free from mill defects, surface cracks, examine the flash weld fusion. Procedures
dents and cuts, especially in the vicinity are to be submitted to IRS for approval.
where gripped by clamping dies during flash Approved procedures and equipment are to
welding. Studs are to be securely fastened. be used. On-site calibration standards for
Chain is to be positioned in order to have chain configurations are to be approved.
good access to all surfaces. In order to
allow optimal access to the surface area it is Every link is to be examined.
recommended that chain be hung in the
vertical position, however access to inspect The flash weld is to be free from defects
the interlink area may only be possible with causing ultrasonic back reflections equal to
the chain in the horizontal position. or greater than the calibration standard. The
flash butt welds are to be ultrasonic tested
b) Testing is to be performed in accordance (UT) in accordance with ASTM E587 or
with a recognized standard and the another recognized standard using single
procedures, together with acceptance / probe, angle-beam shear waves in the
rejection criteria are to be submitted to IRS range from 45 to 70°.
for review. Manufacturers are to prepare
written procedures for NDE. NDE personnel Single probe technique has limitations as far
are to be qualified and certified according to as testing of the central region is concerned
ISO 9712, ACCP or equivalent. Personnel and the flash weld imperfections such as flat
qualification to an employer or responsible spots may have poor reflectivity. Where it is
agency based qualification scheme as SNT- deemed necessary, detectability of
TC-1A may be accepted if the employer's imperfections may need to be carried out by
written practice is reviewed and found using a tandem technique, TOFD or phased
acceptable and the Level III is ASNT Level array.
III, ISO 9712 Level III or ACCP Professional
Level III and certified in the applicable e) Stud welds, if used, are to be visually
method. NDE operators are to be qualified inspected. The toes of the fillets are to have
to at least level II. a smooth transition to the link with no
undercuts exceeding 1.0 [mm]. Additionally,
c) Magnetic particle testing is to be employed at least 10% of the stud welds distributed
to examine the flash welded area including through the length are to be dye penetrant
the area gripped by the clamping dies. tested according to ASTM E1417 or
Procedures are to be submitted to IRS for magnetic particle tested according to ASTM
approval. Approved procedures and E1444 or equivalent. Cracks, lack of fusion
equipment are to be used. Every link is to or gross porosity are not acceptable. If
be examined. Additionally, 10% of links are defects are found, testing is to be extended
to be tested on all accessible surfaces. to all stud welds in that length.

Link surface at the flash weld is to be free 5.13.6 Retest, rejection and repair criteria
from cracks, lack of fusion and gross
porosity. Testing is to be performed in a) If the length over 5 links is short, the chain
accordance with ASTM E709 or another may be stretched by loading above the
recognized standard (e.g. ISO 9934) using proof test load specified provided that the
wet continuous fluorescent magnetization applied load is not greater than that
technique. Non fluorescent techniques can approved and that only random lengths of
be accepted in special cases where the the chain need stretching. If the length
standard inspection procedures are exceeds the specified tolerance, the
impractical. overlength chain links are to be cut out and
the requirements of 5.13.6(b) applied.
Links are to be free from:
- relevant linear indications exceeding 1.6 b) If single links are found to be defective or do
mm in transverse direction not meet other applicable requirements,
- relevant linear indications exceeding 3.2 defective links may be cut out and a
mm in longitudinal direction connecting common link inserted in their
- relevant non-linear indications exceeding place. The individual heat treatment and
4.8 mm. inspection procedure of connecting common
links is subject to the approval of the
Surveyor. Other methods of repair are

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subject to approval of the Surveyor and the recognized that the preceding flash butt
end purchaser. Weld repair of chain is not welded link and subsequent flash butt
permitted. welded link will be on an alternative
chain length or the other end of the
c) If a crack, cut or defect in the flash weld is chain length. In such cases IRS may
found by visual or magnetic particle require that two additional break tests
examination, it is to be ground down no are to be taken from the lengths of chain
more than 5 per cent of the link diameter in that include the preceding and
depth and streamlined to avoid any sharp subsequent welded links. Based upon
contours. However, the final dimensions are satisfactory results of both break tests
to conform to the agreed standard. and the results of the failure
investigation, it will be decided what
d) If indications of interior flash weld defects in length of chain can be considered for
reference to the accepted calibration acceptance. Failure of either or both
standards are detected during ultrasonic breaking tests will result in rejection of
examination, requirements of 5.13.6(b) are the same proof loaded length.
applied.
Replacement of defective links is to be in
e) If link diameter, length, width and stud accordance with the requirements of
alignment do not conform to the required 5.13.6(b). If the investigation identifies
dimensions, these are to be compared to defects in the flash butt weld or a lower
the dimensions of 40 more links; 20 on each strength flash weld “a glue-weld” is found,
side of the affected link. If a single particular additional NDT such as phased array UT is
dimension fails to meet the required to be carried out to identify if other links are
dimensional tolerance in more than 2 of the affected. A full assessment of the flash butt
sample links, all links are to be examined welding machine is to be carried out,
and requirements of 5.13.6(b) are applied. together with assessment of the condition of
the bar ends prior to welding.
f) If a break load test fails, a thorough
examination is to be carried out to identify h) If the tensile test fails to meet the
the cause of failure. Two additional break requirements, a retest of two further
test specimens representing the same specimens selected from the same sample
sampling length of chain are to be subjected will be permissible. Failure to meet the
to the break load test. Based upon specified requirements of either or both
satisfactory results of the additional tests additional tests will result in rejection of the
and the results of the failure investigation, it sampling length of chain represented and
will be decided what lengths of chain can be requirements of 5.13.6(b) are applied.
accepted. Failure of either or both additional
tests will result in rejection of the sampling i) If the impact test requirements are not
length of chain represented and achieved, a retest of three further
requirements of 5.13.6(b) are applied. specimens selected from the same sample
will be permissible. The results are to be
g) If a link fails during proof load testing, a added to those previously obtained to form
thorough examination is to be carried out to a new average. The new average is to
identify the probable cause of failure of the comply with the requirements. No more than
proof load test. In the event that two or more two individual results are to be lower than
links in the proof loaded length fail, that the required average and no more than one
section of proof loaded length is to be result is to be below 70 per cent of the
rejected. specified average value.

The above mentioned failure investigation is Failure to meet the requirements will result
to especially aim at ascertaining the in rejection of the sampling length
presence in other lengths of factors or represented and requirements of 5.13.6(b)
conditions thought to be causal to failure. are applied.

In addition, a break test specimen is to 5.13.7 Marking

be taken from each side of the one
failed link and subjected to the breaking .1 The chain is to be marked at the following
test. Where multiple chains are places:
produced simultaneously it is

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- At each end. c) All accompanying documents, appendices

and reports are to carry reference to the
- At intervals not exceeding 100 m. original certificate number.

- On connecting common links. d) The manufacturer will be responsible for

storing, in a safe and retrievable manner, all
- On links next to shackles or connecting documentation produced for a period of at
common links. least 10 years.

All marked links are to be stated on the 5.14 Testing and inspection of accessories
certificate, and the marking is to make it
possible to recognize leading and tail end of 5.14.1 General
the chain. In addition to the above required
marking, the first and last common link of a) Requirements in 5.14 apply to but is not
each individual charge used in the limited to mooring equipment accessories such
continuous length is to be traceable and as detachable connecting links (shackles),
adequately marked. detachable connecting plates (triplates), end
shackles, swivels, swivel shackles and subsea
The marking is to be permanent and legible connectors.
throughout the expected lifetime of the
chain. b) Prior to test and inspection the chain
accessories are to be free from scale, paint or
.2 The chain is to be marked on the studs as other coating.
follows:
c) All accessories are to be subjected to proof
- Chain grade load tests sample, break load tests and sample
mechanical tests after final heat treatment in the
- Certificate No. presence of a Surveyor. Where the
manufacturer has a procedure to record proof
- IRS stamp loads and the Surveyor is satisfied with the
adequacy of the recording system, he may not
The Certificate number may be exchanged witness all proof load tests. The Surveyor is to
against an abbreviation or equivalent, in satisfy himself that the testing machines are
which case the details are to be stated in calibrated and maintained in a satisfactory
the certificate. condition.

The chain certificate will contain information d) For accessory production a Manufacturing
on number and location of connecting Procedure Specification (MPS) is to be
common links. The certificate number and submitted to IRS that details all critical aspects
replacement link number may be exchanged of accessory production, casting, forging, heat
against an abbreviation or equivalent, in treating (including arrangement and spacing of
which case, the details are to be stated in components in the heat treatment furnaces),
the certificate. quenching, mechanical testing, proof and break
loading and NDE.
5.13.8 Documentation
5.14.2 Proof and break load tests
a) A complete Chain Inspection and Testing
Report in booklet form is to be provided by a) All accessories are to be subjected to the
the chain manufacturer for each continuous proof load specified for the corresponding
chain length. This booklet is to include all stud link chain.
dimensional checks, test and inspection
reports, NDT reports, process records, b) Chain accessories are to be tested to the
photographs as well as any nonconformity, break test loads prescribed for the grade
corrective action and repair work. and size of chain for which they are
intended. At least one accessory out of
b) Individual certificates are to be issued for every 25 accessories is to be tested.
each continuous single length of chain.

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For individually produced, individually heat stress locations to monitor that the
treated accessories or accessories produced in strains stay within allowable limits.
small batches (less than 5), alternative testing
will be subject to special consideration and the 5.14.3 Dimensions and dimensional tolerances
following additional conditions may apply:
a) After proof load testing, at least one
(i) Alternative testing is described in a accessory (of the same type, size and
written procedure and manufacturing nominal strength) out of 25 is to be checked
procedure specification (MPS). for dimensions in accordance with 5.12.9.
The manufacturer is to provide an adequate
(ii) A finite element analysis is provided evidence indicating compliance with the
at the break load and demonstrates that purchaser's requirements.
the accessory has a safety margin over
and above the break load of the chain. b) The following tolerances are applicable to
accessories:
(iii) Strain age testing (as per procedure
approved by IRS) is carried out on the - Nominal diameter : +5 percent, -0 percent
material grade produced to the same - Other dimensions :  2 ½ percent.
parameters at the time of qualification.
These tolerances do not apply to machined
(iv) If an accessory is of a large size that surfaces.
will make heat treating in batches
unfeasible or has a unique design, 5.14.4 Mechanical tests
strain gauges are to be applied during
the proof and break load tests during a) Accessories are to be subjected to
initial qualification and during mechanical testing as described in 5.8 and 5.9.
production. The strain gauge results Mechanical tests are to be taken from proof
from production are to be comparable loaded full size accessories that have been heat
with the results from qualification. treated with the production accessories they
represent. At least one accessory out of every
A batch is defined as accessories that batch or every 25 accessories, whichever is
originate from the same heat treatment less, is to be tested. Hardness tests are to be
charge and the same heat of steel. carried out on finished accessories. The
Accessories which have been subjected frequency and locations are to be agreed with
to a break test are to be scrapped, in IRS. The recorded values are for information
general. However, where the only and used as an additional check to verify
accessories are of increased that the heat treatment process has been stable
dimensions or alternatively a material during the accessory production. The use of
with higher strength characteristics is separate representative coupons is not
used, they may be included in the outfit permitted except as indicated in e) below.
at the discretion of IRS provided that:
b) Test location of forged shackles. Forged
v) the accessories are successfully shackle bodies and forged Kenter shackles are
tested at the prescribed breaking load to have a set of three impact tests and a tensile
appropriate to the chain for which they test taken from the crown of the shackle. Tensile
are intended, and tests on smaller diameter shackles can be taken
from the straight part of the shackle, where the
vi) it is verified by procedure tests that geometry does not permit a tensile specimen
such accessories are so designed that from the crown. The tensile properties and
the breaking strength is not less than impact values are to meet the requirements of
1.4 times the prescribed breaking load Table 5.7.1 in the locations specified in Fig.2.4.1
of the chain for which they are intended. of Section 2 with the Charpy pieces on the
outside radius.
vii) strain age properties have been
carried out on the material grade c) The locations of mechanical tests of cast
produced to the same parameters. shackles and cast Kenter shackles can be taken
from the straight part of the accessory. The
viii) strain gauges are to be applied tensile properties and impact values are to meet
during the break load test in the high the requirements of Table 5.7.1 in the locations
specified in Fig.2.4.1 of Section 2.

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d) The locations of mechanical tests of other

accessories with complex geometries are to be
agreed with IRS.

For non-circular sections, 1/4t (thickness) from

the surface is considered appropriate.

Rolled plates are to be tested to the Standard to Fig.5.14.4 : Buffer and test piece location
which they are produced.

e) For individually produced (heat treated) 5.14.5 Non-destructive examination after proof
accessories or accessories produced in small load testing
batches, (less than 5), alternative testing can be
proposed to IRS. Each proposal for alternative a) All chain accessories are to be subjected to
testing is to be detailed by the manufacturer in a a close visual examination. Special attention
written procedure and submitted to IRS. The is to be paid to machined surfaces and high
following additional conditions may apply: stress regions. Prior to inspection, chain
accessories are to have a suitably prepared
i) If separately forged or cast coupons are surface as per the applied NDE testing
used, they are to have a cross-section and, standard. All non-machined surfaces, are to
for forged coupon, a reduction ratio similar be sand or shot blast to permit a thorough
to that of the accessories represented, and examination. Where applicable,
are to be heat treated in the same furnace accessories shall be dismantled for
and quenched in the same tank at the inspection of internal surfaces. All
same time, as the actual forgings or accessories are to be checked by magnetic
castings. Thermocouples are to be particle or dye penetrant testing. UT of
attached to the coupon and to the accessories may be required by the
accessories. Surveyor. The acceptance /rejection criteria
of UT established for the design is to be
ii) If separately forged or cast coupons are met.
agreed, it is to be verified by procedure test
that coupon properties are representative b) Testing is to be performed in accordance
of accessory properties. with a recognized standard, such as those
indicated below, or equivalent. The
f) A batch is defined as accessories that procedures, together with acceptance /
originate from the same heat treatment charge rejection criteria are to be submitted to IRS
and the same heat of steel. for review.

g) Mechanical tests of pins are to be taken as Magnetic particle testing (MT) of forgings: -
per Fig.2.4.1 of Section 2 from the mid length of EN 10228-1, ASTM A275, using wet
a sacrificial pin of the same diameter as the final continuous magnetization technique or
pin. For oval pins the diameter taken is to equivalent standards such as ISO 4986,
represent the smaller dimension. Mechanical IACS Rec 69
tests may be taken from an extended pin of the
same diameter as the final pin that incorporates Ultrasonic testing (UT) of forgings:
a test prolongation and a heat treatment buffer - EN 10228-3, ASTM A388, ISO 13588
prolongation, where equivalence with mid length
test values have been established. The length of Magnetic particle testing (MT) of castings: -
the buffer is to be at least equal to 1 pin ASTM E709, using wet continuous
diameter dimension which is removed after the magnetization technique
heat treatment cycle is finished. The test coupon
can then be removed from the pin. The buffer Ultrasonic testing (UT) of castings: - ASTM
and test are to come from the same end of the A609, ISO 13588
pin as per Fig.5.14.4 below:

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All surfaces are to be magnetic particle 5.14.7 Marking
tested (MT). Testing is to be performed in
accordance with standards referenced using .1 Each accessory is to be marked as follows:
the fluorescent technique. As a minimum
surfaces are to be free from: - Chain grade

- relevant linear indications exceeding 1.6 - Certificate No.

mm in transverse direction
- IRS stamp
- relevant linear indications exceeding 3.2
mm in longitudinal direction .2 All detachable component parts are to be
stamped with a serial number to avoid mixing of
- relevant non-linear indications exceeding components.
4.8 mm.
.3 The Certificate number may be exchanged
When required by the Surveyor, ultrasonic against an abbreviation or equivalent, in which
testing is to be carried out on 100% of cast case, the details are to be stated in the
or forged accessories. The acceptance / certificate.
rejection criteria established for the design
is to be met. 5.14.8 Documentation

Manufacturers are to prepare written .1 A complete Inspection and Testing Report in

procedures for NDE. NDE personnel are to booklet form is to be provided by the
be qualified and certified according to ISO manufacturer for each order. This booklet is to
9712, ACCP or equivalent. Personnel include all dimensional checks, test and
qualification to an employer or responsible inspection reports, NDT reports, process
agency based qualification scheme as SNT- records and example photographs of
TC-1A may be accepted if the employer's components positioned in furnaces as well as
written practice is reviewed and found any nonconformity, corrective action and repair
acceptable and the Level III is ASNT Level work
III, ISO 9712 Level III or ACCP Professional
Level III and certified in the applicable .2 Each type of accessory is to be covered by
method. NDE operators are to be qualified separate certificates.
to at least level II.
.3 All accompanying documents, appendices
c) The manufacturer is to provide adequate and reports are to carry reference to the original
evidence that non-destructive examination certificate number.
has been carried out with satisfactory
results together with details of technique .4 The manufacturer will be responsible for
used and to the operator's qualification. storing, in a safe and retrievable manner, all
documentation produced for a period of at least
d) Weld repair of finished accessories is not 10 years.
permitted.
5.15 Chafing chain for single point mooring
5.14.6 Test failures arrangements

In the event of a failure of any test the entire 5.15.1 Scope

batch represented is to be rejected unless the
cause of failure is determined and it is These requirements apply to short lengths
demonstrated to the Surveyor's satisfaction that (approximately 8 m) of 76 [mm] diameter chain
the condition causing the failure is not present in to be connected to hawsers for the tethering of
any of the remaining accessories. oil tankers to single point moorings, FPSO’s and
similar uses.

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5.15.2 Approval of manufacturing c) The common link is to be of the stud link

type and of Grade R3 or R4.
The chafing chain is to be manufactured by
works approved by IRS according to 5.3 of this d) The chafing chain is to be capable of
chapter. Also refer Chapter 1, Section 1, Cl. withstanding the breaking test loads of 4884
1.3.2. [kN] (Grade R3) and 6001 [kN] (Grade R4).

5.15.3 Materials Documented evidence of satisfactory testing

of similar diameter mooring chain in the
The materials used for the manufacture of the prior six month period may be used in lieu of
chafing chain are to satisfy the requirements of break testing subject to agreement with IRS.
5.7 to 5.10 of this chapter.
e) The chain lengths shall be proof load tested
5.15.4 Design, manufacturing, testing and in accordance with 5.13.2. The proof test
certification loads for Grade R3 and Grade R4 are to be
3242 [kN] and 4731 [kN] respectively.
a) The chafing chain is to be designed,
manufactured, tested and certified in f) The requirements herein are also applicable
accordance with 5.11 to 5.14 except that to other diameter chafing chains, such as 84
batch heat treatment is permitted. [mm] and 96 [mm], subject to compliance
with the proof and break load requirements
b) The arrangement of the end connections is specified for the chain grade and diameters
to be of an approved type. in Table 5.12.1

End of Chapter

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Chapter 11

Approval of Welding Consumables for Use in Ship Construction

Contents
Section

1 General
2 Electrodes for Normal Penetration Manual Welding
3 Deep Penetration Electrodes for Manual Welding
4 Wire-flux Combinations for Submerged Arc Automatic Welding
5 Wires and Wire-gas Combinations for Semi-automatic and Automatic Welding
6 Consumables for use in Electro-slag and Electro-gas Vertical Welding
7 Welding Consumables for High Strength Steels for Welded Structures
8 Consumables for Welding of Aluminium Alloys

Section 1

General

1.1 Scope e) Higher strength steels for welded structures.

1.1.1 This Chapter gives the requirements for f) Aluminium alloys (See Ch.9).
approval and inspection of welding consumables
such as electrodes, wires, fluxes etc. intended 1.2 Manufacture
for welding of the following types of materials
used in ship construction: 1.2.1 The manufacturer's plant and method of
production of welding consumables are to be
a) Normal strength steel for ship structures, such as to ensure reasonable uniformity in
Grades A, B, D and E (See Ch.3). manufacture. IRS is to be notified of any
alteration proposed to be made in the process of
b) Higher strength steels for ship structures manufacture subsequent to approval.
Grades AH32, DH32, EH32, AH36, DH36
and EH36 (See Ch.3). 1.3 Grading

c) Higher strength steels for ship structures 1.3.1 Welding consumables for steel materials
with minimum yield strength 390 [N/mm2] : specified in 1.1.1 a) to d) above.
Grades AH40, DH40 and EH40 (See Ch.3).
These consumables are divided into 3 strength
d) Higher strength steels for ship structures for groups each of which is further graded as per
low temperature application : Grades FH32, the Charpy V-notch impact test requirements as
FH36 and FH40 (See Ch.3). shown below:

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Groups Grading
Normal strength steel 1, 2, 3
Higher strength steel : yield strength upto 355 [N/mm2] 1Y, 2Y, 3Y, 4Y
Higher strength steels : yield strength upto 390 [N/mm2] 2Y40, 3Y40, 4Y40, 5Y40
Hydrogen marks
Welding consumables of Grades 2 and 3; and of Grades 2Y, 3Y and 4Y and of Grades 2Y40, 3Y40,
4Y40 and 5Y40 for which hydrogen content has been controlled in accordance with Sec.2.5 are
identified by the mark H15, H10 or H5

The following suffixes are added after the Grade mark as applicable:
S : Semi-automatic
T : Two-run technique
M : Multi-run technique
TM : Both two-run and multi-run technique
V : Vertical
Groups Grading
Normal strength steel 1, 2, 3
Higher strength steel : yield strength upto 355 [N/mm2] 1Y, 2Y, 3Y, 4Y
Higher strength steels : yield strength upto 390 [N/mm2] 2Y40, 3Y40, 4Y40
Hydrogen marks
Welding consumables of Grades 2 and 3; and of Grades 2Y, 3Y and 4Y and of Grades 2Y 40, 3Y 40
and 4Y 40, for which hydrogen content has been controlled in accordance with Sec.2.5 are identified
by the mark H, HH or HHH

The following suffixes are added after the Grade mark as applicable:
S : Semi-automatic
T : Two-run technique
M : Multi-run technique
TM : Both two-run and multi-run technique
V : Vertical

See Table 1.3.1 for correlation of welding 1.3.3 For grading of consumables for welding
consumables to hull structural steel grades. aluminium alloys indicated in 1.1.1f) above, refer
to Sec.8.
1.3.2 For grading of consumables for welding
higher strength quenched and tempered steels
indicated in 1.1.1e) above, refer to Sec.7.

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Table 1.3.1 : Correlation of welding consumables to hull structural steel grades

Grades of Hull structural steel Grades 1)

Welding
AH32 DH32 EH32 FH32/
Consumables A B D E AH40 DH40 EH40 FH40
/36 /36 /36 36
(see notes)
1, 1S, 1T, 1M,
X
1TM, 1V
1YS, 1YT, 1YM,
X X 3)
1YTM, 1YV
2, 2S, 2T, 2M,
X X X
2TM, 2V
2Y, 2YS, 2YT,
X X X X X
2YM, 2YTM, 2YV
2Y40, 2Y40S,
2Y40T, 2Y40M, 2) 2) 2) X X X X
2Y40TM, 2Y40V
3, 3S, 3T, 3M,
X X X X
3TM, 3V
3Y, 3YS, 3YT,
X X X X X X X
3YM, 3YTM, 3YV
3Y40, 3Y40S,
3Y40T, 3Y40M, 2) 2) 2) 2) X X X X X X
3Y40TM, 3Y40V
4Y, 4YS, 4YT,
X X X X X X X X
4YM, 4YTM, 4YV
4Y40, 4Y40S,
4Y40T, 4Y40M, 2) 2) 2) 2) X X X X X X X X
4Y40TM, 4Y40V
5Y40, 5Y40S,
5Y40T, 5Y40M, 2) 2) 2) 2) X X X X X X X X
5Y40TM, 5Y40V

1) Requirements for other grades of steels given in ch.3 but not included here will be specially considered.
2) See Note d)
3) See Note e)

a) When joining normal to higher strength structural steel, consumables of the lowest acceptable grade for either material being
joined may be used.
b) When joining steels of same strength level but of different toughness grade, consumables of the lowest acceptable grade for
either material being joined may be used.
c) It is recommended that controlled low hydrogen type consumables are to be used when joining higher strength structural
steels to the same or lower strength level, except that other consumables may be used when the carbon equivalent is below
or equal to 0.41%. When other than controlled low hydrogen type electrodes are used appropriate procedure test for
hydrogen cracking may be conducted subject to approval of IRS.
d) The welding consumables approved for steel Grades AH40, DH40, EH40 and/or FH40 may also be used for welding of the
corresponding grades of normal strength steels subject to the approval of IRS.
e) When joining higher strength steels using Grade 1Y welding consumables, the material thicknesses is not to exceed 25
[mm].

1.4 Approval procedure that the materials and the fabrication process
used are identical with those of the main unit.
1.4.1 Approval of welding consumables will be
considered on the basis of the manufacturer's This requirement is also applicable to all
description of the works and detailed description manufacturers of welding consumables under
of the method of production control, satisfactory license.
inspection of the works by the Surveyors and
compliance with the test requirements detailed Note : In case of wire flux combination for
in subsequent paragraphs of this Chapter. submerged arc welding where a unique powder
flux is combined with different wires coming from
1.4.2 When a welding consumable is several factories belonging to the same firm only
manufactured in several locations of the same one test series may be carried out provided the
company, the complete series of approval tests wires conform to the same technical
would be carried out in one Works only. In other specification.
locations, a reduced test programme based
upon the requirements of annual testing may be 1.4.3 The test assemblies are to be prepared
accepted subject to the manufacturer certifying under the supervision of the Surveyor, and all
tests are to be carried out in his presence.

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1.8 Dimensions of test specimens

1.4.4 IRS may require, in any particular case,
such additional tests or spacing requirements as 1.8.1 Deposited metal tensile test specimens
may be necessary. are to be machined to the dimensions shown in
Fig.1.8.1. Care is to be taken to ensure that the
1.5 Test assemblies longitudinal axis of the test piece coincides with
the centre of the weld and midthickness of the
1.5.1 The test assemblies are to be prepared plates. The test piece may be heated to a
and tested under the supervision of the temperature not exceeding 250C for a period
Surveyor(s). not exceeding 16 hours for hydrogen removal,
prior to testing.
1.5.2 When a welded joint is performed, the
edges of the plates are to be bevelled either by
mechanical machining or by oxygen cutting; in
the latter case, a descaling of the edges is
necessary.

1.5.3 The welding conditions used such as

amperage, voltage, travel speed, etc. are to be
within the range recommended by the
manufacturer for normal and good welding
practice. Where a welding consumable is
suitable for both alternating current (AC) and
direct current (DC), AC is to be used for the
preparation of test assemblies.
Fig.1.8.1 : Deposited metal tensile test
1.6 Annual inspection and tests

1.6.1 All establishments, where approved

welding consumables are manufactured, and
the associated quality control procedures, are to
be subjected to annual inspection. On these
occasions, samples of the approved
consumables are to be selected by the Surveyor
and subjected to the tests detailed in the
subsequent paragraphs of this Chapter.

1.7 Upgrading and uprating

1.7.1 Upgrading and uprating of welding

consumables will be considered only at the
Fig.1.8.2 : Butt weld tensile test specimen
manufacturer's request, preferably at the time of
annual testing. Generally, for this purpose, tests
from butt weld assemblies will be required in 1.8.2 Butt weld tensile test specimens are to be
addition to the normal annual approval tests. machined to the following dimensions (see
Fig.1.8.2).
1.7.2 Upgrading refers to notch toughness of the
welding consumable while uprating refers to a = thickness of plate ‘t’
extension to cover higher strength level steels. b = 12 for t  2 [mm]
= 25 for t > 2 [mm]
1.7.3 Any alteration to the approved consumable Lc = width of weld + 60 [mm]
which may result in a change in the chemical R > 25 [mm].
composition and the mechanical properties of
the deposited metal, must be immediately The upper and lower surfaces of the weld are to
notified by the manufacturer. Additional tests be filed, ground or machined flush with the
may be necessary. surface of the plates.

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1.8.3 Butt weld bend test specimens are to be The test temperature for Grades 2, 2Y, 2Y40, 3,
30 [mm] in width. Upper and lower surfaces of 3Y, 3Y40, 4Y, 4Y40 and 5Y40 test pieces is to
the weld are to be filed, ground or machined be controlled within ±2C of the prescribed
flush with the surfaces of the plates and sharp temperature.
corners of the specimens are to be rounded to a
radius not exceeding 2 [mm]. 1.10 Re-test procedures

1.8.4 All impact test specimens are to be of the 1.10.1 Where the results of a tensile or bend
standard 10 [mm] x 10 [mm] Charpy V-notch test do not comply with the requirements,
type, machined to the dimensions and duplicate test specimens of the same type are to
tolerances detailed in Ch.2. be prepared and are to be satisfactorily tested.
Where insufficient original welded assembly is
1.9 Testing procedures available, a new assembly is to be prepared
using welding consumables from the same
1.9.1 The procedures used for all tensile and batch. If the new assembly is made with the
impact tests are to comply with the requirements same procedure (particularly the number of
of Ch.2. runs) as the original assembly, only the
duplicate re-test specimens need to be tested.
1.9.2 Butt weld bend test specimens are to be Otherwise, all test specimens are to be prepared
tested at ambient temperature. The test and re-tested.
specimens are to be capable of withstanding,
without fracture, being bent through an angle of 1.10.2 Where the results from a set of three
120 degrees over a former having a diameter impact test specimens do not comply with the
three times the thickness of the specimen. One requirements, an additional set of three impact
specimen from each welded assembly is to be test specimens may be taken provided that not
tested with the face of the weld in tension and more than two individual values are less than
the other with the root of the weld in tension. the required average value and, of these, not
The test pieces can be considered as complying more than one is less than 70 per cent of the
with the requirements if, on completion of the average value. The results obtained are to be
test, no crack or defect at the outer surface of combined with the original results to form a new
the test specimen can be seen. average which, for acceptance, is to be not less
than the required value. Additionally, for these
1.9.3 Tensile Tests : On deposited metal test combined results not more than two individual
specimens, the values of tensile strength, yield values are to be less than the required average
stress and elongation are to be recorded. On value, and of these, not more than one is to be
butt weld specimens, the values of tensile less than 70 per cent of the average value.
strength and the position of fracture are to be Further retests may be made at the Surveyor's
recorded. discretion, but these must be made on a new
welded assembly and must include all tests
1.9.4 Charpy V-notch Impact Tests : A set of required for the original assembly, even those
three test specimens is to prepared and tested. which were previously satisfactory.
The average absorbed energy value is to
comply with the requirements of subsequent 1.11 Chemical composition
sections. One individual value may be less than
the required average value provided that it is not 1.11.1 The chemical analysis of the weld metal
less than 70 per cent of this value. made by the electrode is to be supplied by the
manufacturer.

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Section 2

Electrodes for Normal Penetration Manual Welding

2.1 General be used for the preparation of these test

assemblies.
2.1.1 Based on the results of the Charpy V-
notch impact tests, electrodes are divided into 2.2.2 The weld metal is to be deposited in single
the following grades:- or multi-run layers according to normal practice
and the direction of each layer is to alternate
For normal strength steel - Grades 1, 2 and 3 from each end of the plate, each run of the weld
metal being not less than 2 [mm] and not more
For higher strength steel with minimum yield than 4 [mm] thick. Between each run the
strength upto 355 [N/mm2] - Grades 2Y, 3Y and assembly is to be left in still air until it has cooled
4Y. (Grade 1Y not applicable for manual to 250C but not less than 100C, the
welding). temperature being taken in the centre of the
weld, on the surface of the seam. After being
For higher strength steels with minimum yield welded the test assemblies are not to be
strength upto 390 [N/mm2] - Grades 2Y40, subjected to any heat treatment.
3Y40, 4Y40 and 5Y40.
2.2.3 One tensile and three impact test
2.1.2 If the electrodes are in compliance with the specimens are to be taken from each test
requirements of the hydrogen test given in 2.5, a assembly as shown in Fig.2.2.1. The impact test
suffix H15, H10 or H5 will be added to the grade specimens are to be cut perpendicular to the
mark. weld, with their axes 10 [mm] from the upper
surface of the plate. The notch is to be
2.1.3 For initial approval the tests specified in positioned in the centre of the weld and cut in
this Section including hydrogen test, if the face of the test specimen perpendicular to
applicable, are to be carried out. the surface of the plate.

2.2 Deposited metal tests 2.2.4 The chemical analysis of the deposited
weld metal in each test assembly is to be
2.2.1 Two deposited metal test assemblies are supplied by the manufacturer and is to include
to be prepared in the downhand position as the content of all significant alloying elements.
shown in Fig.2.2.1, one using 4 [mm] electrodes
and the other using the largest size 2.2.5 The results of all tests are to comply with
manufactured. If an electrode is manufactured in the requirements of Table 2.2.1 as appropriate.
one diameter only, one test assembly is
sufficient. Any grade of ship structural steel may

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Table 2.2.1 : Requirements for deposited metal tests (covered electrodes)

Minimum Impact Tests

Tensile
Yield stress elongation on
Grade strength Average
[N/mm2] min. 50 mm gauge Test temp. C
[N/mm2] energy J min.
length [%]
1 20
2 305 400 - 560 22 0 47
3 -20
2Y 0
3Y 375 490 - 660 22 -20 47
4Y -40
2Y40 0
3Y40 -20
400 510 - 690 22 47
4Y40 -40
5Y40 -60

Fig.2.2.1 : Deposited metal test assembly

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2.3 Butt weld tests manufacturer, except that electrodes satisfying

the requirements for downhand and vertical-
2.3.1 Butt weld assemblies as shown in upward positions will be considered as also
Fig.2.3.1 are to be prepared for each welding complying with the requirements for the
position (downhand, horizontal-vertical, vertical- horizontal-vertical position.
upward, vertical-downward and overhead) for
which the electrode is recommended by the

Fig.2.3.1 : Butt weld test assembly

Table 2.3.1 : Requirements for butt weld test (covered electrodes)

Charpy V-notch impact test

Tensile
strength Average energy J min.
Grade [N/mm2] min. Down-hand
(transverse Test temp. C horizon-tal Vertical (upward and down-
test) vertical, over- ward)
head
1 20
2 400 0 47 34
3 -20
2Y 0
3Y 490 -20 47 34
4Y -40
2Y40 0
3Y40 -20
510 47 39
4Y40 -40
5Y40 -60

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2.3.2 Where the electrode is only to be First run with 4 [mm] diameter electrode. Next
approved in the downhand position an additional run with an intermediate size electrode 5 [mm]
test assembly is to be prepared in that position. or 6 [mm] diameter and the remaining runs with
the largest size of electrode manufactured.
2.3.3 The grades of steels used for the
preparation of the test assemblies are to be as HORIZONTAL-VERTICAL
follows:
First run with 4 [mm] or 5 [mm] diameter
Grade 1 electrodes A electrode, subsequent runs with 5 [mm]
diameter electrodes.
Grade 2 electrodes A, B, D
VERTICAL UPWARDS AND OVERHEAD
Grade 3 electrode A, B, D, E
First run with 3.25 [mm] diameter electrode.
Grade 2Y electrode AH32, AH36, Remaining runs with 4 [mm] diameter electrodes
D32, D36 or possibly 5 [mm] diameter electrodes if this is
recommended by the manufacturer for the
Grade 3Y electrode AH32, AH36, positions concerned.
DH32, DH36,
EH32, EH36 VERTICAL DOWNWARD

Grade 4Y electrodes AH32, AH36, The method to be adopted is to be as

DH32, DH36, recommended by the manufacturer.
EH32, EH36,
FH32, FH36 2.3.6 In all cases the back sealing runs are to be
made with 4 [mm] diameter electrodes in the
Grade 2Y40 electrodes AH40, DH40 welding position appropriate to each test sample
after cutting out the root run to clean metal. For
Grade 3Y40 electrodes AH40, DH40, electrodes suitable for downhand welding only,
EH40 the test assemblies may be turned over to carry
out the back sealing run.
Grade 4Y40 electrodes AH40, DH40,
EH40, FH40 2.3.7 The butts are to be welded using normal
welding practice and between each run the
Grade 5Y40 electrodes AH40,DH40, assembly is to be left in still air until it has cooled
EH40, FH40 to 250C but not below 100C, the temperature
being taken in the centre of the weld, on the
2.3.4 Where higher strength steel with minimum surface of the seam.
yield strength 315 [N/mm2] is used for grade 2Y,
3Y and 4Y electrodes, the actual tensile strength 2.3.8 After being welded, the test assemblies
of the steel is to be not less than 490 [N/mm2]. are not to be subjected to any heat treatment.
The chemical composition including the content
of grain refining elements is to be reported. 2.3.9 It is recommended that the welded
assemblies be subjected to a radiographic
2.3.5 The following welding procedure should be examination to ascertain any defects in the weld
adopted in making the test assemblies:- prior to testing.

DOWNHAND (a) 2.3.10 From each test assembly one tensile,

one face and one root bend and a set of three
First run with 4 [mm] diameter electrode. Charpy V-notch test specimens are to be
Remaining runs (except last two layers) with 5 prepared, except that the impact test specimens
[mm] diameter electrodes or above according to need not be prepared for test assemblies
the normal welding practice with the electrodes. welded in the overhead position.
The runs of the last two layers with the largest
size of electrode manufactured. 2.3.11 The results of all mechanical testing are
to comply with the requirements of Table 2.3.1.
DOWNHAND (b) The position of the fracture in the transverse
tensile test is to be reported. The bend test
Where a second downhand test is required:- specimens can be considered as complying with
the requirements if, after bending, no crack or

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defect having dimensions exceeding 3 [mm] can a) Diamond Pyramid Hardness (98 N load) =
be seen on the outer surface of the test 150 minimum
specimen.
b) Rockwell (980 N load) B = 80 minimum
2.4 Fillet weld tests

2.4.1 When an electrode is submitted for

approval for fillet welding only and to which butt
weld tests, as per 2.3, are not considered
applicable, the initial approval tests are to
consist of the fillet weld test, described herein,
and the deposited metal test as per 2.2. When
the electrode is submitted for approval for both
butt and fillet welding, the initial approval is to
include one fillet weld test as detailed hereunder
and welded in the horizontal-vertical position in
addition to the tests required by 2.2 and 2.3.

2.4.2 Fillet weld assemblies as shown in

Fig.2.4.1 are to be prepared for each welding
position (horizontal-vertical, vertical-upwards,
vertical- downwards or overhead) for which the
electrode is recommended by the manufacturer.
The grade of steel used is to be in accordance
2.4.4 The hardness of both heat affected zone
with 2.3.3 as appropriate. The test assemblies
and base metal is also to be determined and is
are to be welded using an electrode of a
to be reported for information.
diameter recommended by the manufacturer.
The length of the test assembly, L, is to be
2.4.5 One of the remaining sections of the
sufficient to allow at least the deposition of the
assembly is to have the weld on the first side
entire length of the electrode being tested.
gouged or machined to facilitate breaking the
fillet weld on the second side by closing the two
plates together, subjecting the root of the weld
to tension. On the other remaining section the
weld on the second side is to be gouged or
machined and the section fractured using the
same procedure. The fractured surfaces are to
be examined and there should be no evidence
of incomplete penetrations, nor internal cracking
and they should be reasonably free from
porosity.

2.5 Hydrogen test

2.5.1 At the request of the manufacturer,

The first side is to be welded using the electrodes may be submitted to a hydrogen test.
maximum size of electrode manufactured and A suffix H15, H10 or H5 will be added to the
the second side is to be welded using the grade number to indicate compliance with the
minimum size of electrode manufactured and requirements of this test.
recommended for fillet welding. The fillet size
will in general be determined by the electrode 2.5.2 The mercury method or thermal
size and the welding current employed during conductivity detector method according to
testing. standard ISO 3690 is to be used. Four weld
assemblies are to be prepared. The temperature
2.4.3 The assembly is to be sectioned to form of the specimens and minimum holding time are
three macro sections each about 25 [mm] thick to be complied with following, according to the
and the hardness readings are to be made in measuring method respectively:
each section as indicated in Fig.2.4.2. The
hardness of the weld is to be determined and is
to meet the following listed equivalent values:-

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corrected for temperature and pressure to
Measuring Method Test Minimum 20C and 760 [mm] Hg.
Temp Holding
(° C) Time 2.5.4 The individual and average diffusible
Thermal Gas 45 72 hydrogen contents of the four specimens are to
Conductiv Chromat 150 6 be reported, and the average value in [cm3] per
ity ography 100 grams is not to exceed the following:
Detector
Method 1 Mark Diffusible Measuring Method
Note 1 - The use of hot carrier gas extraction Hydrogen
method may be considered subject to Contents
verification of the testing procedure to confirm H15 151 Mercury Method
that collection and measurement of the H10 102 Thermal Conductivity
hydrogen occurs continuously until all of the Detector Method
diffusible hydrogen is quantified. Glycerine Method
H5 5 Mercury Method
Thermal Conductivity
Alternatively, the glycerine method as described Detector Method
below is to be used. 1 – 10 cm3 per 100 gms where the glycerine
method is used
2.5.3 Glycerine method 2 – 5 cm3 per 100 gms where the glycerine
method is used
a) Four test specimens are to be prepared Note :- The glycerine method is not to be used
measuring 12 x 25 [mm] in cross- section by for welding consumables with H5 mark.
about 125 [mm] in length. The parent metal
may be any grade of ship building steel and,
before welding, the specimens are to be 2.6 Covered electrodes for gravity or contact
weighed to the nearest 0.1 gram. On the 25 welding
[mm] surface of each test specimen a single
bead of welding is to be deposited about 2.6.1 Where an electrode is submitted solely for
100 [mm] in length by a 4 [mm] electrode approval for use in contact welding using
using about 150 [mm] of the electrode. The automatic gravity or similar welding devices,
welding is to be carried out with as short an deposited metal tests (see 2.2), fillet weld tests
arc as possible and with a current of about (see 2.4) and, where appropriate, butt weld tests
150 amperes. The electrode prior to (see 2.3) similar to those for normal manual
welding, can be submitted to the normal electrodes are to be carried out using the
drying process recommended by the process for which the electrode is recommended
manufacturer. by the manufacturer.

b) Within thirty seconds of the completion of 2.6.2 Where an electrode is submitted for
welding of each specimen the slag is to be approval for use in contact welding using
removed and the specimen quenched in automatic gravity or similar welding devices in
water at approximately 20C. After a further addition to normal manual welding, fillet weld
thirty seconds the specimens are to be tests (see 2.4) and, where appropriate, butt weld
cleaned and placed in an apparatus suitable tests (see 2.3) similar to those for normal
for the collection of hydrogen by manual electrodes are to be carried out using
displacement of glycerine. The glycerine is the process for which the electrode is
to be kept at a temperature of 45C during recommended by the manufacturer and these
the test. All the four specimens are to be tests are to be in addition to the normal approval
welded and placed in the hydrogen tests.
collecting apparatus within 30 minutes.
2.6.3 In the case of approval of a fillet welding
c) The specimens are to be kept immersed in electrode using automatic gravity or similar
the glycerine for a period of 48 hours and, contact welding devices, the fillet welding is to
after removal, are to be cleaned in water be carried out using the welding process
and spirit, dried and weighed to the nearest recommended by the manufacturer, with the
0.1 gram to determine the amount of weld longest size of electrode manufactured. The
deposited. The amount of gas evolved is to manufacturer's recommended current range is
be measured to the nearest 0.05 [cm3] and to be reported for each electrode.

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2.6.4 Where approval is requested for the 2.8 Upgrading and uprating
welding of both normal strength and higher
tensile steels, the assemblies are to be prepared 2.8.1 Upgrading and uprating will be considered
using higher tensile steel. only at the manufacturer's request and
preferably at the time of annual testing. Tests on
2.7 Annual tests butt weld assemblies, in addition to the
requirements of annual testing, are to be carried
2.7.1 For normal penetration electrodes, the out.
annual tests are to consist of two deposited
metal test assemblies. These are to be prepared 2.9 Certification
and tested in accordance with 2.2. If an
electrode is available in one diameter only, one 2.9.1 Each carton or package of approved
test assembly is sufficient. electrode is to contain a certificate from the
manufacturer generally in accordance with the
2.7.2 Where an electrode is approved solely for following:-
gravity or contact welding, the annual test is to
consist of one deposited metal test assembly "The .......... company certifies that composition
using the gravity or other contact device as and quality of these electrodes conform with
recommended by the manufacturer. those of the electrodes used in making the test
pieces submitted to and approved by Indian
Register of Shipping."

Section 3

Deep Penetration Electrodes for Manual Welding

3.1 General 3.1.5 Where the manufacturer prescribes a

different welding current and procedure for the
3.1.1 Where an electrode is designed solely for electrode when used as a deep penetration
the deep penetration welding of downhand butt electrode and a normal penetration electrode,
joints and horizontal-vertical fillets, only the test the recommended current and procedure are to
detailed in 3.2 and 3.3 are required for initial be used when making the test specimens in
approval purposes. each case.

3.1.2 Deep penetration electrodes will only be 3.2 Deep penetration butt weld tests
approved as complying with Grade 1
requirements. The suffix D.P. will be added. 3.2.1 Two plates of thickness equal to twice the
diameter of the core of the electrode plus 2 [mm]
3.1.3 Where a manufacturer recommends that are to be butt welded together with one
an electrode having deep penetrating properties downhand run of welding from each side. The
can also be used for downhand butt welding of plates are to be not less than 100 [mm] wide
thicker plates with prepared edges, the and of sufficient length to allow the cutting out of
electrode will be treated as normal penetration the test specimens of the correct number and
electrode, and the full series of tests in the size as shown in Fig.3.2.1. Grade A steel is to
downhand position is to be carried out as per be used for these test assemblies. The joint
normal penetration electrode, together with deep edges are to be prepared square and smooth
penetration tests given in 3.2 and 3.3. and, after tacking, the gap is not to exceed 0.25
[mm].
3.1.4 Where a manufacturer desires to
demonstrate that an electrode in addition to its 3.2.2 The test assembly is to be welded using a
use as normal penetration electrode also has 8 [mm] diameter electrode or the largest
deep penetrating properties when used for diameter size manufactured if this is less than 8
downhand butt welding and horizontal - vertical [mm].
fillet welding, the additional tests given in 3.2
and 3.3 are to be carried out.

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3.2.3 After welding the test assembly is to be cut 3.2.4 The discards at the end of the welded
to form two transverse tensile test pieces, two assemblies are to be not more than 35 [mm]
bend test pieces and three Charpy V-notch test wide. The joints of these discards are to be
pieces as shown in Fig.3.2.1. The results of polished and etched and must show complete
tensile and impact testing are to comply with the fusion and interpenetration of the welds. At each
requirements of Table 2.3.1 for Grade 1 cut in the test assembly the joints are also to be
electrodes. examined to ensure that complete fusion has
taken place.

Thickness of plate twice core

of electrode plus 2 mm

35 mm
Discard

Charpy V-notch

30 mm 30 mm
Face bend

Root bend

50 mm
Transverse tensile

50 mm
Transverse tensile
35 mm

Discard

0.25 mm
max.
100 mm min. 100 mm min.

Fig. 3.2.1 : Deep penetration butt weld

test assembly

3.3 Deep penetration fillet weld test

3.3.1 A fillet weld assembly is to be prepared as

shown in Fig.3.3.1 with plates about 12.5 [mm]
in thickness. The welding is to be carried out
with one run for each fillet with plate A in the
horizontal plane during the welding operations.
The length of the fillet is to be 160 [mm] and the
gap between the plates is to be not more than
0.25 [mm]. Grade A steel is to be used for these
test assemblies.

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3.3.2 The fillet weld on one side of the assembly automatic gravity or similar welding devices in
is to be carried out with 4 [mm] electrode and addition to normal manual welding, butt weld
that on the other side with the maximum size of and, where appropriate, fillet weld tests, using
the electrode manufactured. The welding current gravity or other contact device as recommended
used is to be within the range recommended by by the manufacturer, are to be carried out in
the manufacturer and the welding is to be addition to the normal approval tests.
carried out using normal welding practice.
3.5 Annual tests
3.3.3 The welded assembly is to be cut by
sawing or machining within 35 [mm] of the ends 3.5.1 Where an electrode is approved only for
of the fillet welds and the joints are to be deep penetration welding, the annual test is to
polished and etched. The welding of the fillet consist of one butt welded test assembly in
made with a 4 [mm] electrode is to show a accordance with 3.2.
penetration of 4 [mm] (See Fig.3.3.1) and the
corresponding penetration of the fillet made with 3.5.2 Where an electrode is approved for both
the maximum size of electrode manufactured is normal and deep penetration welding, annual
to be reported. tests are to consist of following:-

3.4 Electrodes designed for gravity or a) Two deposited metal test assemblies in
contact welding accordance with 2.2; and

3.4.1 This type of approval is available for b) One butt welded test assembly in
welding only normal strength and higher tensile accordance with 3.2.
steels with minimum specified yield strengths up
to 345 [N/mm2]. 3.5.3 Where an electrode is approved solely for
gravity or contact welding, the annual test is to
3.4.2 Where an electrode is submitted solely for consist of one deposited metal test assembly
approval for use in contact welding using using the gravity or other contact device as
automatic gravity or similar welding devices, recommended by the manufacturer.
deposited metal tests, and where appropriate,
fillet weld tests similar to those for normal 3.6 Certification
manual electrodes are to be carried out using
the process for which the electrode is 3.6.1 Each carton or package of approved
recommended by the manufacturer. electrodes is to contain a certificate from the
manufacturer generally in accordance with 2.9.
3.4.3 Where an electrode is submitted for
approval for use in contact welding using

Section 4

Wire-flux Combinations for Submerged Arc Automatic Welding

4.1 General Wire-flux combinations for multiple electrode

submerged arc welding will be subject to
4.1.1 Wire-flux combinations for single electrode separate approval tests. They are to be carried
submerged-arc automatic or semi-automatic out generally in accordance with the
welding are divided into following two requirements of this section.
categories:-
4.1.2 Dependent on the results of impact tests,
a) For use with multi-run technique; wire-flux combinations are divided into the
following grades:-
b) For use with two-run technique.
For normal strength steel - Grades 1, 2 or 3;
Where wire-flux combinations are suitable for
welding with both the techniques, tests are to be For higher strength steel with minimum yield
carried out for each technique. strength upto 355 [N/mm2] - Grades 1Y, 2Y, 3Y
or 4Y.

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For higher strength steels with minimum yield 200
strength upto 390 [N/mm2] - Grades 2Y40, 10°
3Y40, 4Y40 or 5Y40.

4.1.3 The suffixes T, M or TM will be added to

20
the grade mark to indicate two-run technique,

12
multi-run technique or both techniques Tack weld
16
respectively.
50

4.1.4 The welding current may be either a.c. or

d.c. (electrode positive or negative) according to
the recommendation of the manufacturer. If both
a.c. and d.c. are recommended, a.c. is to be Tensile
used for the tests.

4.2 Multi-run technique

30
4.2.1 When approval for use with multi-run
technique is required, deposited metal and butt

10 10 10 10 10
weld tests are to be carried out in accordance
with 4.3 and 4.4 respectively. Impact

4.3 Deposited metal tests

4.3.1 An all weld metal test assembly is to be Line of cut

prepared in the downhand position as shown in Tensile
Fig.4.3.1, using any grade of hull structural
steel.

4.3.2 The bevelling of the plate edges is to be 30

carried out by machining or mechanized gas
cutting. In the latter case any remaining scale is
All dimensions in mm unless otherwise indicated
to be removed from the bevelled edges.
Fig. 4.3.1 : Deposited metal test assembly
4.3.3 The direction of deposition of each run is
to alternate from each end of the plate and after 4.3.5 The welded assembly is to be cut
completion of each run the flux and welding slag longitudinally at a distance of 30 [mm] from the
is to be removed. Between each run the edges of the weld and then cut transversely.
assembly is to be left in still air until it has cooled
to 250C but not below 100C, the temperature 4.3.6 Two longitudinal tensile and three impact
being taken in the centre of the weld, on the test specimens are to be taken from each test
surface of the seam. The thickness of the layer assembly as shown in Fig.4.3.1. Care is to be
is to be not less than the diameter of the wire taken that the axes of the tensile test specimens
but not less than 4 [mm]. coincide with the centre of the weld and the
midthickness of the plates. The impact test
4.3.4 The welding conditions (amperage, specimens are to be cut perpendicular to the
voltage and rate of travel) are to be in weld with their axes 10 [mm] from the upper
accordance with the recommendations of the surface. The notch is to be positioned in the
manufacturer and are to conform with normal centre of the weld and cut in the face of the test
good welding practice for multi-run welding. specimen perpendicular to the surface of the
plate.

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4.3.7 The results of all tests are to comply with 12 to 15 [mm] and 20
requirements of Table 4.3.1 as appropriate. The For Grades 1 and 1Y
to 25 [mm]
chemical analysis of the deposited weld metal For Grades 2, 2Y, 3, 20 to 25 [mm] and 30
including the content of the significant alloying 3Y and 4Y to 35 [mm]
elements is to be submitted by the
For Grades 2Y40,
manufacturer. 20 to 25 [mm] and 30
3Y40, 4Y40 and
to 35 [mm]
5Y40
Table 4.3.1 : Requirements for deposited
A limitation of the approval to the medium range
metal tests (wire-flux combinations)
(upto the maximum welded plate thickness) may
Elon- Charpy V-
be agreed in which case the test assemblies are
gation notch impact to be welded using plates of 12 to 15 [mm] and
Yield
Tensile on 50
Avg.
20 to 25 [mm] irrespective of the grade for which
stren- mm the approval is requested.
Grade stress Test ener
gth gauge
[N/mm2] temp. gy -
[N/mm2] length
C J Where approval is requested for welding of both
%
min.
min. normal strength and higher tensile steel, two
1
400 -
20 assemblies are to be prepared using higher
2 305 22 0 34
560 tensile steel.
3 -20
1Y 20
2Y 490 - 0 4.4.2 The maximum diameter of wire, grades of
375 22 34
3Y 660 -20 steel plate and edge preparation to be used are
4Y -40 to be in accordance with Table 4.4.2. Small
2Y40 0
3Y40 510 - -20 deviations in the edge preparation may be
400 22 39 allowed if requested by the manufacturer. The
4Y40 690 -40
5Y40 -60 bevelling of the plate edges is to be performed
by machining or mechanized gas cutting. In the
4.4 Butt weld test (two-run technique) latter case any remaining scale is to be removed
from the bevelled edges. The root gap should
4.4.1 Two welded assemblies for each grade of not exceed 1.0 [mm].
wire-flux combination are to be prepared in
accordance with Fig.4.4.1, using the following
plate thicknesses:-

Table 4.4.2 : Butt weld test assemblies (two-run technique)

Plate Recommended preparation Max. Grade of Grade of Grade of higher strength

thick- [mm] diameter wire-flux normal steel
ness of wire combi- strength
[mm] [mm] nation steel
1 A -
About
5 AH32
12 -15 1Y -
AH36
1 A -
1Y - AH32, AH36
2 A,B or D -
2Y - AH32, AH36, DH32, DH36
2Y40 - AH40, DH40
About 3 A,B,D or E -
6
20 - 25 AH32, AH36, DH32
3Y -
DH36, EH32, EH36
3Y40 - AH40, DH40, EH40
AH32, AH36, DH32, DH36
4Y -
EH32, EH36, FH32, FH36
4Y40 - AH40, DH40, EH40, FH40
5Y40 - AH40, DH40, EH40, FH40

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2 A, B or D -
2Y - AH32, AH36, DH32, DH36
2Y40 - AH40, DH40
3 A, B, D or E -
About H32, AH36, DH32, DH36,
7 3Y -
30 - 35 EH32, EH36
3Y40 - AH40, DH40, EH40
AH32, AH36, DH32, DH36,
4Y -
EH32, EH36, FH32, FH36
4Y40 - AH40, DH40, EH40, FH40
5Y40 - AH40, DH40, EH40, FH40

Fig.4.4.1 : Butt weld test assembly (two-

run technique)

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4.4.3 The welding current may be either a.c. or

d.c. (electrode positive or negative) according to 4.4.6 It is recommended that welded assemblies
the recommendation of the manufacturer. If both be subjected to radiographic examination to
a.c. and d.c. are recommended a.c. is to be ascertain any defects in the weld prior to testing.
used for test pieces.
4.4.7 The assemblies are to be cut transversely,
4.4.4 Each butt weld is to be welded in two runs, to form two tensile test pieces and two bend test
one from each side, using amperages, voltages pieces as shown in Fig.4.4.1, three impact test
and travel speeds in accordance with the pieces as shown in Fig.4.4.1 and Fig.4.4.3. The
recommendations of the manufacturer and edges of all test pieces and also the discards
normal good welding practice. are to be examined to ensure complete fusion
and interpenetration of welds.
4.4.5 After completion of the first run, the flux
and welding slag are to be removed and the 4.4.8 Where the wire-flux combination is to be
assembly is to be left in still air until it has cooled used for two-run technique only, a longitudinal
to 100C, the temperature being taken in the test is also to be made in accordance with
centre of the weld, on the surface of the seam. Fig.4.5.1 on the thicker plate tested.
After being welded the test assemblies are not
to be subjected to any heat treatment. 4.4.9 The results of the transverse tensile and
impact tests are to comply with the requirements
of Table 4.5.1 as appropriate. The results of
longitudinal tensile test are to comply with the
requirements of Table 4.3.1 as appropriate
except that for Grades 1Y, 2Y and 3Y the tensile
strength is not to be less than 490 [N/mm2].

4.5 Butt weld test (multi-run technique)

4.5.1 A butt weld assembly, as shown in

Fig.4.5.1, is to be prepared in the downhand
position by welding together two 20 [mm] thick
plates of not less than 150 [mm] in width and of
sufficient length to allow the cutting out of test
specimens of the prescribed number and size.

4.5.2 The grade of steel used for the preparation

of the test assembly is to be as follows:-

Grade 1 wire-flux combination Grade A

Grade 2 wire-flux combinations Grade A, B, D
Grade 3 wire-flux combinations Grade A, B, D, E
Grade 1Y wire-flux combinations Grade AH32, AH36
Grade 2Y wire-flux combinations AH32, AH36, DH32, DH36
Grade 3Y wire-flux combinations AH32, AH36, DH32, DH36, EH32, EH36
Grade 4Y wire-flux combinations AH32, AH36, DH32, DH36, EH32, EH36,
FH32, FH36
Grade 2Y40 wire-flux combinations AH40, DH40
Grade 3Y40 wire-flux combinations AH40, DH40, EH40
Grade 4Y40 wire-flux combinations AH40, DH40, EH40, FH40
Grade 5Y40 wire-flux combinations AH40, DH40, EH40, FH40

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Fig 4.5.1 Multi-run butt weld test assembly (Submerged arc welding)

4.5.3 Welding is to be carried out in the

downhand position, and the direction of 4.5.4 The plate edges are to be prepared to
deposition of each run is to alternate from each form a single vee joint, the included angle
end of the plate. After completion of each run, between the fusion faces being 60 degrees and
the flux and welding slag is to be removed. the root face being 4 [mm]. The bevelling of the
Between each run the assembly is to be left in plate edges is to be carried out by machining or
still air until it has cooled to less than 250C but mechanized gas cutting. In the latter case, any
not below 100C, the temperature being taken in remaining scale is to be removed from the
the centre of the weld, on the surface of the bevelled edges.
seam. The thickness of the layer is to be not
less than the diameter of the wire nor less than 4.5.5 The welding is to be carried out by the
4 [mm]. multi-run technique and the welding conditions

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are to be the same as those adopted for the

deposited metal test assembly. 4.5.8 The test assembly is to be cut to form two
tensile; two face bend; two root bend; three
4.5.6 The back sealing run is to be applied in the impact test pieces as shown in Fig.4.5.1.
downhand position after cutting out the root run
to clean metal. After being welded the test 4.5.9 The results of all tensile and impact test
assembly is not to be subjected to any heat specimens are to comply with the requirements
treatment. of Table 4.5.1 as appropriate. The position of
the fracture of the transverse tensile test is to be
4.5.7 It is recommended that the welded reported.
assembly be subjected to radiographic
examination to ascertain any defects in the weld
prior to testing.

Table 4.5.1 : Requirements for butt weld tests (wire flux-combination)

Tensile strength Charpy V-notch impact test

Grade (transverse test) [N/mm2] Avg. energy J min.
Test temp. C
min. (See note)
1 20
2 400 0 34
3 -20
1Y 20
2Y 0
490 34
3Y -20
4Y -40
2Y40 0
3Y40 -20
510 39
4Y40 -40
5Y40 -60
Note : No individual impact test value is to be less than 23J

4.6 Annual tests b) For multi-run technique :- Deposited metal

Tests - One tensile and three impact tests in
4.6.1 Following tests on wire-flux combinations accordance with 4.3.
are to be carried out at the time of annual
inspection:- 4.6.2 The specimens are to be prepared and
tested in accordance with, and on grades of
a) For two-run technique :- On butt weld steel specified for initial approval tests and the
assembly with 20 [mm] minimum plate results are to comply with the results of the
thickness : One transverse tensile, two approved grade.
transverse bends and three impact tests.
One longitudinal tensile test specimen is 4.7 Upgrading and uprating
also to be prepared where the wire-flux
combination is approved solely for the two- 4.7.1 Requests for upgrading and uprating will
run technique. generally be considered at the time of annual
testing and additional tests in accordance with
the requirements of 2.8 would be required.

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Section 5

Wires and Wire-gas Combinations for Semi-automatic and

Automatic Welding

5.1 General 5.1.4 For wires intended for automatic welding,

the suffixes T, M or TM will be added after the
5.1.1 Wire-gas combinations and flux-cored or grade mark to indicate approval for two-run,
flux-coated wires (for use with or without a multi- run or both welding techniques,
shielding gas) are divided into following respectively.
categories for the purposes of approval testing:-
5.1.5 For wires intended for both semi-automatic
a) For use in semi-automatic multi-run welding; and automatic welding, the suffixes will be
added in combination.
b) For use in single electrode multi-run
automatic welding; and 5.1.6 Where applicable, the composition of the
shielding gas is to be reported. Unless otherwise
c) For use in single electrode two-run agreed, additional approval tests are required
automatic welding. when the shielding gas is different from that
used for the original approval tests.
5.1.2 The term 'semi-automatic' is used to
describe processes in which the weld is made Where a wire in combination with any particular
manually by a welder holding a gun through gas has been approved, usage of the same wire
which the wire is continuously fed. A suffix S will with another gas in the same group as defined
be added after the grade mark to indicate in Table 5.1.6 may be considered.
approval for semi-automatic multi-run welding.
5.1.7 Flux-cored or flux-coated wires which have
5.1.3 Dependent on the results of impact tests, satisfied the requirements for Grades 2, 2Y,
wires and wire-gas combinations are divided 2Y40, 3, 3Y, 3Y40, 4Y, 4Y40 and 5Y40 may, at
into the following grades:- the option of the manufacturer, be submitted to
the hydrogen test as detailed in 2.5 using the
For normal strength Grades 1, 2 and manufacturer's recommended welding condi-
steel 3 tions and adjusting the deposition rate to give a
For higher strength steel Grades 1Y, 2Y, weight of weld deposit per sample similar to that
with minimum yield 3Y and 4Y. deposited when using manual electrodes. A
strength upto 355 suffix H15, H10 or H5 will be added to the grade
[N/mm2] mark, in the same conditions as for manual arc
For higher strength Grades 2Y40, welding electrodes to indicate compliance with
steels with minimum 3Y40, 4Y40 and the requirements of the test.
yield strength upto 390 5Y40
[N/mm2]

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Table 5.1.6 : Compositional limits of designated groups of gas types and mixtures

Group Gas Composition (Vol. %)

CO2 O2 H2 Ar
M1 1 > 0 to 5 - > 0 to 5
2 > 0 to 5 - -
Rest 1) 2)
3 - > 0 to 3 -
4 > 0 to 5 > 0 to 3 -
M1 1 > 5 to 25 - -
2 - 3 to 10 - Rest 1) 2)
3 > 5 to 25 > 0 to 3 -
M1 1 > 25 to 50 - -
2 - > 10 to 15 - Rest 1) 2)
3 > 5 to 50 > 8 to 15 -
C 1 100 - -
Rest 1) 2)
2 Rest > 0 to 30 -

1) Argon may be substituted by Helium upto 95% of the Argon content.

2) Approval covers gas mixtures with equal or higher Helium contents only.

5.2 Approval tests for two-run automatic prepared using plates approximately 20 [mm] in
welding thickness and the other using plates of
maximum thickness for which approval is
5.2.1 Approval tests for two-run automatic requested.
welding are to be carried out generally in
accordance with the requirements of Sec.4 5.2.4 The edge preparation of test assemblies is
using the two-run automatic welding technique to be as shown in Fig.5.2.1. Small deviations in
for the preparation of all test assemblies. the edge preparation may be allowed, if
requested by the manufacturer. For assemblies
using plates over 25 [mm] in thickness, the edge
preparation is to be reported for information.

5.3 Approval tests for semi-automatic multi-

run welding

5.3.1 Approval tests for semi-automatic multi-run

welding are to be carried out generally in
accordance with the requirements of Sec.2,
using the semi-automatic multi-run technique for
the preparation of all test assemblies.

5.3.2 Two deposited metal test assemblies are

Fig.5.2.1 : Recommended edge preparation to be prepared in the downhand position as
for two-run butt weld test assemblies shown in Fig.2.2.1, one using the smallest
diameter, and the other using the largest
diameter of the wire intended for the welding of
ship structures. The weld metal is to be
5.2.2 Two butt weld test assemblies are to be deposited according to the practice
prepared generally as detailed in 4.4.1 and 4.4.2 recommended by the manufacturer, and the
using plates 12-15 [mm] and 20-25 [mm] in thickness of each layer of weld metal is to be
thickness. between 2 [mm] and 6 [mm]. Where only one
diameter is manufactured, only one deposited
5.2.3 If approval is requested for welding plates metal assembly is to be prepared.
thicker than 25 [mm], one assembly is to be

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5.3.3 Butt weld assemblies as shown in 5.5 Annual tests
Fig.2.3.1 are to be prepared for each welding
position (downhand, horizontal-vertical, vertical- 5.5.1 The annual tests are to consist of at least
upwards, vertical-downwards and overhead) for the following:-
which the wire is recommended by the
manufacturer. a) Wires approved for semi-automatic or for
both semi-automatic and automatic multi-
5.3.4 The downhand assembly is to be welded run welding: One deposited metal test
using, for the first run, wire of 1.2 [mm] diameter assembly prepared in accordance with 5.3
or of the smallest diameter manufactured and, using a wire of diameter within the range
for the remaining runs, wire of 2.4 [mm] intended for the welding of the ship
diameter or the largest diameter manufactured. structures;

5.3.5 Where approval is requested only in the b) Wires approved for automatic multi-run
downhand position, an additional butt weld welding: One deposited metal test assembly
assembly is to be prepared in that position using prepared in accordance with 5.4 using a
wires of different diameter from those required wire of diameter within the range intended
by 5.3.4. for the welding of the ship structure;

5.3.6 The butt weld assemblies, in positions c) Wires approved for two-run automatic
other than downhand, are to be welded using for welding: One butt weld test assembly
the first run, wire of 1.2 [mm] diameter or of the prepared in accordance with 5.2 using
smallest diameter manufactured, and for the plates 20 to 25 [mm] in thickness. The
remaining runs, the largest diameter of wire diameter of the wire used is to be reported.
recommended by the manufacturer for the
position concerned. 5.5.2 From the test assemblies prepared in
accordance with 5.5.1, only the following tests
5.3.7 Fillet weld test in accordance with Sec.2 is are to be carried out:-
to be carried out.
a) For deposited metal assemblies: One
5.4 Approval tests for multi-run automatic tensile and three impact tests;
welding
b) For butt weld assemblies: One transverse
5.4.1 Approval tests for multi-run automatic tensile, two bend and three impact tests.
welding are to be carried out generally in One longitudinal tensile test is also required
accordance with the requirements of Sec.4 where the wire is approved solely for two-
using the multi-run automatic welding technique run automatic welding.
for the preparation of all test assemblies.
5.6 Upgrading and uprating
5.4.2 One deposited metal test assembly is to
be prepared as shown in Fig.4.3.1. Welding is to 5.6.1 Requests for upgrading and uprating will
be as detailed in Sec.4 except that thickness of generally be considered at the time of annual
each layer is to be not less than 3 [mm]. testing and additional tests in accordance with
the requirements of 2.8 would be required.
5.4.3 A butt weld assembly is to be prepared, as
shown in Fig.4.5.1.

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Section 6

Consumables for use in Electro-slag and

Electro-gas Vertical Welding

6.1 General 6.2.2 Radiographic examination

6.1.1 The requirements for the two-run It is recommended that the welded assemblies
technique as detailed in Sec.4 are applicable for be subjected to a radiographic examination to
the approval of special consumable used in ascertain if there are any defects in the weld
electro-slag and electro-gas vertical welding with prior to the preparation of test specimens.
or without consumable nozzles except as
otherwise required by the following requirements 6.2.3 Test series
especially as regards the number and kind of
the test-pieces used for the mechanical tests - Each assembly shall be cut to give test
and taken from the butt welded assemblies. specimens according to Fig.6.2.1.

6.1.2 For Grades 1Y, 2Y, 3Y, 4Y, 2Y40, 3Y40, The length of the assembly should be sufficient
4Y40 and 5Y40 approval of the consumables to allow the selection of all the following test
may be restricted for use only with specific types specimens :
of higher tensile steel. This is in respect of the
content of grain refining elements, and if general 250 mm min. 250 mm min.
approval is required, a niobium treated steel is
to be used for the approval tests.

6.1.3 For these special welding consumables,

Longitudinal tensile
the requirements of 1.3 may not be entirely test specimen
applicable for technical reasons. (centre of weld)

Where approval is requested for welding of both Transverse tensile

test specimen
normal strength and higher tensile steel two Side bend
assemblies are to be prepared using higher test specimen
Macrography
tensile steel. Two assemblies prepared using
normal strength steel may also be required at 1 set of 3 charpy
the discretion of IRS. V-notch test specimen
1500 mm min

(centre line)

6.2 Butt weld tests 1 set of 3 charpy

V-notch test specimen
(2 mm from fusion line)
6.2.1 Preparation of test assemblies
Transverse tensile
- Two butt weld test assemblies are to be test specimen
Side bend
prepared, one of them with plates 20/25 test specimen
[mm] thick, the other with plates 35/40 [mm]
thick or more. The grade of the steel to be Longitudinal tensile
test specimen
used for each one of these assemblies must (centre of weld)
be selected according to the requirements
given in the Table 4.4.2. Macrography

- The chemical composition of the plate,

including the content of grain refining
Fig. 6.2.1 : Butt weld test assembly
elements is to be reported.

- The welding conditions and the edges

preparation are to be those recommended - 2 longitudinal tensile test specimens
by the welding consumable manufacturer with their axis at the centre of the weld;
and are to be reported.
- 2 transverse tensile test specimens;

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- 2 side bend test specimens;
- 1 transverse tensile specimen;
- 2 sets of 3 Charpy-V notch impact test
specimens in accordance with Fig.6.2.1 - 2 side bend specimens;
comprising of :
- 3 Charpy-V specimens notched at the
- 1 set with the notch in the axes of the centre of the weld (position 1 Fig.6.3.1);
weld;
- 3 Charpy-V specimens cut out
- 1 set with the notch at 2 [mm] from the transverse to the weld with their notches
fusion line in the deposited metal; and at 2 [mm] from the fusion line, in the
weld; and
- 2 macro-sections of the weld (towards
the middle of the weld and towards one - macro section.
end).
6.3.2 The results to be obtained should meet the
6.2.4 Results to be obtained requirements given in 4.4 (two-run welding) for
the class of the consumables in question.
The results of the tensile, bend and impact tests
are to comply with the requirements of 4.4 (two- 6.4 Upgrading and uprating
run welding) for the class of filler product in
question. 6.4.1 Upgrading and uprating will be considered
only at the manufacturers request, preferably at
6.3 Annual tests the time of annual testing. Generally, for this
purpose, full tests from butt weld assemblies as
6.3.1 One test assembly must be prepared from indicated in 6.2 will be required, irrespective of
plates 20/25 [mm] thick, and tested as indicated the other tests requested if the concerned
in 6.2. consumable is also approved (and possibly
upgraded or uprated) according to Sec.4 or
The following specimens are to be selected : Sec.5.

- 1 longitudinal tensile specimen from the

axis of the weld:

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Section 7

Welding Consumables for High Strength Steels for Welded Structures

7.1 General Y69 for welding steels with minimum yield

strength 690 [N/mm2]
7.1.1 Scope
Y89 for welding steels with minimum yield
7.1.1.1 These requirements supplement the strength 890 [N/mm2]
requirements of Sections 1 to 6 and give the
conditions of approval and inspection of welding Y96 for welding steels with minimum yield
consumables used for high strength steels for strength 960 [N/mm2].
welded structures according to Ch.3, Sec.4 with
yield strength levels from 420 [N/mm2] upto 960 Wire-flux combinations for single or two-run
[N/mm2] and impact grades AH, DH, EH and technique are subject to special consideration of
FH, except impact grade FH is not applicable for IRS.
890 [N/mm2] and 960 [N/mm2] yield strength
levels. 7.1.2.2 Each of the eight (yield) strength groups
is further divided into three main grades in
Where no special requirements are given, those respect of charpy V-notch impact test
of Sections 1 to 6 apply in analogous manner. requirements (test temperatures):

7.1.1.2 The welding consumables preferably to Grade Test temperature

be used for the steels concerned are divided 3 - 20C
into several categories as follows:
4 - 40C
- covered electrodes for manual welding, 5 - 60C

- wire-flux combinations for multirun sub- 7.1.2.3 Analogously to the designation scheme
merged arc welding, used in Section 1 to 6 the welding consumables
for high strength steels are subject to additional
- solid wire-gas combinations for arc welding designation and approval as follows:
(including rods for gas tungsten arc
welding),
- According to 7.1.2.2 with the quality grades
3, 4 or 5.
- flux cored wire with or without gas for arc
welding.
- With the added symbol Y and an appended
code number designating the minimum yield
7.1.2 Grading, Designation
strength of the weld metal corresponding to
7.1.2.1 : Y42, Y46, Y50, Y55, Y62, Y69, Y89
7.1.2.1 Based on the yield strength of the weld and Y96.
metal, the welding consumables concerned are
divided into eight (yield) strength groups:
- With the added symbol H10 or H5 for
controlled hydrogen content of the weld
Y42 for welding steels with minimum yield
metal.
strength 420 [N/mm2]
- With the added symbol S (= semi-automatic)
Y46 for welding steels with minimum yield
for semi-mechanised welding.
strength 460 [N/mm2]
- With the added symbol M designating
Y50 for welding steels with minimum yield
multirun technique and is applicable only to
strength 500 [N/mm2] welding consumables for fully mechanised
welding).
Y55 for welding steels with minimum yield
strength 550 [N/mm2]
7.1.2.4 Each higher quality grade includes the
one (or those) below, AH, DH steels according
Y62 for welding steels with minimum yield
to Ch.3, Sec.4 are to be welded using welding
strength 620 [N/mm2]
consumables of at least quality grade, 3, grade

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EH steels using at least quality grade 4 and or the side walls of the weld shall be buttered
grade FH steels using at least quality grade 5, with a weld metal of the same composition.
as per the following table:
7.2.2 The chemical composition of the deposited
weld metal shall be determined and certified in a
Consumables Steel Grades manner analogous to that prescribed in Sec.2,
Grade covered Cl.2.2.4. The results of the analysis shall not
3Y.. DH.. exceed the limit values specified in the
4Y.. EH..and FH.. standards or by the manufacturer, the narrower
5Y.. FH.., EH.. and DH.. tolerances being applicable in each case.

7.1.2.5 Welding consumables approved with 7.2.3 Depending on the type of the welding
grades.Y42, ..Y46 and ..Y50 are also consumables (and according to the welding
considered suitable for welding steels in the two process), the test specimens prescribed in
strength levels below that for which they have Sections 1 to 6 respectively shall be taken from
been approved. Welding consumables approved the weld metal test pieces in a similar manner.
with grades ..Y55, ..Y62 and ..Y69 are also
considered suitable for welding steels in the one 7.2.4 The mechanical properties must meet the
strength level below that for which they have requirements stated in Table 7.2.1 and Table
been approved. Welding consumables with 7.2.2. The provisions of Sections 1 to 6 apply in
grade Y89 are considered suitable for welding analogous manner to the performance of the
steels in the same strength level only. Welding tests, including in particular the maintenance of
consumables with grade Y96 are also the test temperature in the notched bar impact
considered suitable for welding steels in the one test and the carrying out of results.
strength level below that for which they have
been approved. For grade Y89 and Y96, where 7.2.5 Specifications of welding consumables
the design requirements permit undermatching used for welding high strength extremely thick
weld joint, then welding consumables within the steel plates of thickness more than 50 [mm] but
scope of this section can be considered subject not exceeding 100[mm] of EH47 grade used in
to IRS’s discretion and Manufacturer’s container carriers are to be in accordance with
recommendations. Table 7.2.3

7.1.2.6 IRS may, in individual cases, restrict the 7.2.6 Welding consumables for brittle crack
range of application in (up to) such a way, that arrest steels are to be in accordance with the
approval for any one strength level does not relevant requirements for each steel grade
justify approval for any other strength level. excluding suffix “BCA1” or “BCA2” specified in
Table 10.1.3 of Chapter 3, Section 10.
7.1.3 Manufacture, testing and approval
procedure 7.3 Testing on welded joints

7.1.3.1 Manufacturer's plant, production 7.3.1 Depending on the type of the welding
methods and quality control measures shall be consumables (and according to the welding
such as to ensure reasonable uniformity in process), the testing on the welded joints shall
manufacture, see also Sec.1. be performed on butt-weld test pieces in a
manner analogous to that called for in Sections
7.1.3.2 Testing and approval procedure shall be 1 to 6.
in accordance with Sec.1 and as required in
Section 1 to 6 for the individual categories 7.3.2 Depending on the type of the welding
(types) of welding consumables mentioned in consumables (and according to the welding
7.1.1.2 above. process), the butt-weld test pieces called for in
para 7.3.1 shall be welded in a manner
7.2 Testing of the weld metal analogous to that prescribed in Sections 1 to 6.
The base metal used shall be a high-strength
7.2.1 For testing the deposited weld metal, test fine-grained structural steel with a minimum
pieces analogous to those called for in Sections yield strength and tensile strength matching the
1 to 6 respectively shall be prepared, depending consumable grade being approved and
on the type of the welding consumables (and compatible with the added symbol for which
according to the welding process). The base application is made.
metal used shall be a fine-gained structural steel
compatible with the properties of the weld metal,

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7.3.3 Depending on the type of the welding provisions of Sections 1 to 6 apply in analogous
consumables (and according to the welding manner to the performance of the tests,
process), the test specimens described in including in particular the maintenance of the
Sections 1 to 6 shall be taken from the butt-weld test temperatures in the notched bar impact test
test pieces. and the requirements regarding the retest
specimens.
7.3.4 The mechanical properties must meet the
requirements stated in Table 7.3.1. The

Table 7.2.1 : Required toughness properties of the weld metal

Quality Grade Test temp.C Min. notch impact energy [J]1)

3 - 20 Y42:  47
Y46:  47
4 - 40 Y50:  50
Y55:  55
5 - 60 Y62:  62
Y69:  69
Y89:  692)
Y96:  692)
1) Charpy V-notch impact test specimen, mean value of three specimens; for
requirements regarding minimum individual values and retests, See Section 1,
1.10
2) Quality grade 5 is not applicable for Y89 and Y96 grade consumables.

Table 7.2.2 : Required strength properties of the weld metal

Symbols added to Min. yield strength or Tensile Strength Minimum elongation

quality grade 0.2% proof stress [N/mm2] [%]
[N/mm2]
Y42 420 520 - 680 20
Y46 460 540 - 720 20
Y50 500 590 - 770 18
Y55 550 640 – 820 18
Y62 620 700 - 890 18
Y69 690 770 - 940 17
Y89 890 940 - 1100 14
Y96 960 980 - 1150 13

Table 7.2.3 : Required strength properties for deposited metal used to weld high strength
extremely thick steel plates of thickness more than 50[mm] but not exceeding 100[mm], of EH47
grade used in container carriers,

Mechanical Properties Impact Test

Yield Strength Tensile Strength Elongation (%) Test Temp. [oC] Average Impact
[N/mm2] min. [N/mm2] min Energy [J] min.
460 570 - 720 19 -20 64

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7.3.5 Where the bending angle required in Table 7.3.6 Mechanical Properties for Butt weld tests
7.3.1 is not achieved, the specimen may be for high strength extremely thick steel plates of
considered as fulfilling the requirements, if the thickness more than 50[mm] but not exceeding
bending elongation on a gauge length Lo fulfills 100[mm], of EH47 grade used in container
the minimum elongation requirements stated in carriers are to be as per Table 7.3.2
Table 7.2.2. The gauge length Lo = Ls + t (Ls =
width of weld, t = specimen thickness), see
Fig.7.3.1.

Table 7.3.1 : Required properties of welded joints

Quality Grade Added symbol Min. tensile Min. notch impact Minimum Bend ratio
strength energy, test bending D/t 2)
[N/mm2] temperature angle 1)
Y42 520 4
Y46 540 4
3 to 5 in Y50 590 Depending on the 4
accordance Y55 640 quality grade and yield 5
120
with Table Y62 700 strength in accordance 5
7.2.1 Y69 770 with Table 7.2.1 5
Y89 940 6
Y96 980 7

Fig.7.3.1 : Required proportion of welded joints

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1) Bending angle attained before the first incipient crack, minor pore exposures upto a maximum length of 3 mm
allowed.

2) D = Mandrel diameter, t = specimen thickness

Table 7.3.2 : Mechanical Properties for Butt weld tests for high strength extremely thick steel
plates of thickness more than 50[mm] but not exceeding 100[mm], of EH47 grade used in
container carriers

Tensile Strength Bend Test Ratio: Charpy V-notch Impact Tests

[N/mm2] D/t
Test Temperature Average Energy (J) min.
(oC)
570-720 4 -20 64

7.4 Hydrogen test 7.4.2 The diffusible hydrogen content of the

weld metal determined in accordance with the
7.4.1 The welding consumables, other than solid provisions of Sec.2, Para 2.5 shall not exceed
wire-gas combinations, shall be subjected to a the limits given in Table 7.4.1.
hydrogen test in accordance with the mercury
method to ISO 3690, or any other method such
as the gas chromatographic method which
correlates with that method, in respect of cooling
rate and delay times during preparation of the
weld samples, and the hydrogen volume
determinations.

Table 7.4.1 : Allowable diffusible hydrogen content

Yield strength group Hydrogen symbol Max. hydrogen content

[cm3/100 g deposited weld
metal]
Y42
Y46 H 10 10
Y50
Y55
Y62 H5 5
Y69
Y89
H5 5
Y96

7.5 Annual tests

7.5.1 The annual repeat tests specified in

Sections 1 to 6 shall entail the preparation and
testing of weld metal test pieces as prescribed
under 7.2. For grades Y69 to Y96 annual
hydrogen test is required. In special cases, IRS
may require more extensive tests.

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Section 8

Consumables for Welding of Aluminium Alloys

8.1 General W = wire electrode, wire - gas combinations for

metal arc inert gas welding (MIG, 131 according
8.1.1 Tests for the approval of consumables to ISO 4063), tungsten inert gas welding (TIG,
intended for welding the aluminium alloys 141) or plasma arc welding (15)
detailed in Ch.9 are to be carried out generally
in accordance with the requirements of Secs.1,2 R = rod - gas combinations for tungsten inert
and 5, except as otherwise detailed in this gas arc welding (TIG, 141) or plasma arc
Section. welding (15)

8.1.2 The welding consumables are divided into 8.1.3 Approval will be indicated by the grade as
two categories as follows: shown in Table 8.1.3.

Table 8.1.3 : Consumables grades and base materials for the approval test

Consumable quality Base material for the tests

grade (Symbol) Alloy Designation
Numerical Chem-Symbol
RA/WA 5754 AlMg3
RB/WB 5086 AlMg4
RC/WC 5083 AlMg4.5 Mn0.7
5383 AlMg4.5 Mn0.9
5456 AlMg5
5059 -
RD/WD 6082 AlSi1MgMn
6005A AlSiMg(A)
6061 AlMg1SiCu
Note: Approval on higher strength AlMg base materials covers also the lower strength AlMg grades and
their combination with AlSi grades

8.1.4 The welding technique will be indicated in 8.1.6 Approval of a wire or a rod will be granted
the approval grading by a letter as under: in conjunction with a specific shielding gas
according to Table 8.1.6 or defined in terms of
m - manual multi-run welding (GTAW); composition and purity of "special" gas to be
S - semi-automatic multi-run welding (GMAW); designated with group sign "S". The composition
M - automatic multi-run welding (GTAW or of the shielding gas is to be reported. Where a
GMAW); wire in combination with any particular gas has
T - automatic two-run welding (GMAW). been approved, usage of the same wire with
another gas in the same group as defined in
8.1.5 The compositions, of the shielding gas and Table 8.1.6 may be considered.
the filler/electrode wire are to be reported.

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Table 8.1.6 : Compositional limits of shielding gases and mixtures to be used

Group Gas composition (Vol.%)1)

Argon Helium
I-1 100 -
I-2 - 100
I-3 Rest > 0 to 33
I-4 Rest > 33 to 66
I-5 Rest > 66 to 95
S Special gas, composition to be specified, See 8.1.6

1) Gases of other chemical composition (mixed gases) may be considered as "special gases" and
covered by a separate test.

8.1.7 On completion of welding, assemblies 8.2.3 Welded assemblies are to be prepared

must be allowed to cool naturally to ambient and tested in accordance with 8.3, 8.4 and 8.5.
temperature. Welded test assemblies and test
specimens must not be subjected to any heat 8.3 Deposited metal test assemblies
treatment after welding except for the alloy
Grades 6005A, 6061 and 6082. These are to be 8.3.1 One assembly is to be prepared in the
allowed to naturally age at ambient temperature downhand position as shown in Fig.8.3.1.
for a period of 72 hours from the completion of
welding, before the testing is carried out. A 8.3.2 The chemical composition of the plate
second solution heat treatment is not permitted. used for the assembly is to be compatible with
The time and temperature of any ageing the weld metal.
treatment is to be reported in detail.
8.3.3 The thickness of the plate used and the
8.2 Initial approval tests for manual, semi- length of the assembly are to be appropriate to
automatic and automatic multi-run the welding process. The plate thickness is to be
techniques not less than 12 [mm].

8.2.1 Plate of the corresponding type of 8.3.4 For the approval of filler wire/gas and
aluminium alloy and of appropriate thickness is electrode wire/gas combinations for manual or
to be used for the preparation of the weld test semi-automatic welding by GTAW or GMAW,
assemblies. one test assembly is to be welded using any
size of wire within the range for which approval
8.2.2 The welding current and power is sought.
requirements are to be within the range
recommended by the manufacturer and are to
be reported.

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The elements reported will be dependent on the

8.3.5 For automatic multi-run approval, one test type of aluminium alloy for which approval of the
assembly is to be welded by the respective consumables is requested. The results of the
process using the recommended diameter of analysis are to be within the tolerances specified
wire. in the standards and by the manufacturer.

8.3.6 The weld metal is to be deposited in multi- 8.4 Butt weld test assemblies
run layers in accordance with normal practice.
The direction of deposition of each layer is to 8.4.1 Plate of the corresponding type of
alternate from each end of the plate. aluminium alloy and of an appropriate thickness
is to be used for the preparation of the test
8.3.7 The deposited weld metal in each test assemblies.
assembly is to be analysed and reported
including the contents of all significant elements.

Table 8.4.1 : Requirements for the transverse tensile and bend tests

Grade Base material Tensile Former Bending angle 1)

used for the test strength Rm diameter [] min.
[N/mm2]
min.
RA/WA 5754 190 3t
RB/WB 5086 240 6t
RC/WC 5083 275
5383 or 5456 290 6t 180
5059 330
RD/WD 6061, 6005A or 6082 170 6t

1) During testing, the test specimen shall not reveal any one single flaw greater than 3 [mm] in any
direction. Flaws appearing at the corners of a test specimen shall be ignored in the evaluation, unless
there is evidence that they result from lack fusion.

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8.4.2 In order to ensure sound and 8.4.3 One additional assembly, as shown in
representative welds, it is essential that test Fig.8.4.3, is to be prepared for welding in the
assemblies are cleaned and degreased prior to downhand position. The assembly is to be
welding. Assemblies as shown in Fig.8.4.2 are welded using, for the first run, wire of the
to be prepared for each welding position smallest diameter recommended by the
(downhand, horizontal-vertical, vertical-upward, manufacturer and for the remaining runs, wire of
vertical-downward and overhead) for which the the largest diameter to be approved.
consumable is recommended by the
manufacturer; except that consumables 8.4.4 The manufacturer's recommended
satisfying the requirements for downhand and procedures are to be used in making the welds
vertical-upward positions will be considered as and are to be reported.
also complying with the requirements for the
horizontal-vertical position. 8.4.5 The welded assemblies should be
subjected to both radiographic and visual
Back sealing runs are allowed in single V weld examination, aided where necessary by dye
assemblies. In case of double V assembly both penetrant testing, to ensure that the welds are
sides shall be welded with the same welding free from cracks and porosity.
position.

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8.4.6 The test specimens are to be taken from recommended by the manufacturer for fillet
the welded assemblies as shown in Fig.8.4.2 welding.
and Fig.8.4.3. For each assembly they are to
comprise: 8.5.2 The results of examination of the macro
specimens and the fractured fillet welds are to
2 transverse tensile specimens; be reported in accordance with 2.4.3 and 2.4.5.
1 macro specimen; Particular attention is to be given to the
2 face bend specimens; and presence of any porosity.
2 root bend specimens.
8.6 Initial approval tests for two-run
8.4.7 All tensile test specimens should have a technique
tensile strength not less than the respective
value shown in Table 8.4.1. The position of each 8.6.1 Two butt weld test assemblies are to be
fracture is to be reported. prepared using the following plate thicknesses
as shown in Fig.8.7.1:
8.4.8 The bend test specimens are to be bent
around a former having a diameter not more a) one with the maximum thickness for which
than the number of times the thickness (t) of the approval is requested;
test specimen as shown in Table 8.4.1.
b) one with a thickness approximately one half
8.5 Fillet weld test assemblies to two thirds that of the maximum thickness.

8.5.1 Assemblies are to be prepared and tested 8.7 Annual tests

in accordance with the appropriate requirements
of 2.4 except that the plates are to be of the 8.7.1 Annual repeat tests are to consist of
aluminium alloy for which approval is required, preparation and testing of the deposited weld
that no hardness tests are required and that for metal test assembly as prescribed in 8.3
automatic multi-run approval only one fillet weld (Fig.8.3.1) and of the downhand buttweld
bead is to be made using the recommended assembly according to 8.4 (Fig.8.4.2).
wire diameter. In this case, the bead size should
be as large as the maximum single bead size

End of Chapter

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