W11

W11 Normal and higher strength hull structural

(1979)
(cont)
(Rev.1
steels
1986)
1. Scope
(Rev. 2
1995 v.2.1)
1.1 These requirements apply to weldable normal and higher strength hot-rolled steel
(Rev.3
plates, wide flats, sections and bars intended for use in hull construction.
June 2000)
(Rev.4
1.2 The requirements are primarily intended to apply to steel products with a thickness as
May
follows:
2001)
(Rev.5 July
For steel plates and wide flats;
2002)
- All Grades: Up to 100mm in thickness
(Rev.6 May
2004)
For sections and bars;
(Rev.7 Apr
- All Grades: Up to 50mm in thickness
2008)
(Corr.1
For greater thickness certain variations in the requirements may be allowed or required in
Feb 2009)
particular cases after consideration of the technical circumstances involved.
(Rev.8
Apr 2014)
1.3 Provision is made for four grades of normal strength steel based on the impact test
(Rev.9
requirements. For higher strength steels provision is made for three strength levels (315, 355
May 2017)
and 390 N/mm2) each subdivided into four grades based on the impact test temperature.

1.4 Steels differing in chemical composition, deoxidation practice, conditions of supply

and mechanical properties may be accepted, subject to the special approval of the
Classification Society. Such steels are to be given a special designation.

Note:

1. Changes introduced in Rev.8 are to be uniformly implemented by IACS Societies on

ships contracted for construction on or after 1 July 2015 and when the application for
certification of steel plates is dated on or after 1 July 2015.

2. Changes introduced in Rev.9 are to be uniformly implemented by IACS Societies on

ships contracted for construction on or after 1 July 2018, or when the application for
certification of steel products is dated on or after 1 July 2018, or the application for
certification of manufacturer approval is dated on or after 1 July 2018.

23. The “contracted for construction” date means the date on which the contract to build the
vessel is signed between the prospective owner and the shipbuilder. For further details
regarding the date of “contract for construction”, refer to IACS Procedural Requirement (PR)
No. 29.

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W11 1.5 These requirements also apply to normal and higher strength Corrosion Resistant
(cont) steels when such steel is used as the alternative means of corrosion protection for cargo oil
tanks as specified in the performance standard MSC.289 (87) of Regulation 3-11, Part A-1,
Chapter II-1 of the SOLAS Convention (Corrosion protection of cargo oil tanks of crude oil
tankers). Corrosion Resistant steels as defined within this UR, are steels whose corrosion
resistance performance in the bottom or top of the internal cargo oil tank is tested and
approved to satisfy the requirements in MSC.289 (87) in addition to other relevant
requirements for hull structural steels, structural strength and construction. It is not intended
that such steels be used for corrosion resistant applications in other areas of a vessel that are
outside of those specified in the performance standard MSC.289 (87) of Regulation 3-11, Part
A-1, Chapter II-1 of the SOLAS Convention. These requirements apply to plates, wide flats,
sections and bars in all grades up to a maximum thickness of 50 mm.

2. Approval

2.1 All materials are to be manufactured at works which have been approved by the
Classification Society for the type and grade of steel which is being supplied. The suitability of
each grade of steel for forming and welding is to be demonstrated during the initial approval
tests at the steelworks. Approval of the steel works is to follow a scheme given in the
Appendix A. For the steels intended for high heat input welding over 50kJ/cm, the approval of
the manufacturer is to follow a scheme given in the Appendix B. For steels intended for a
corrosion resistant designation, the approval of the manufacturer is to additionally follow the
scheme given in Appendix C.

2.2 It is the manufacturer’s responsibility to assure that effective process and production
controls in operation are adhered to within the manufacturing specifications. Where control
imperfection inducing possible inferior quality of product occurs, the manufacturer is to
identify the cause and establish a countermeasure to prevent its recurrence. Also, the
complete investigation report is to be submitted to the Surveyor.

For further use, each affected piece is to be tested to the Surveyor’s satisfaction.

The frequency of testing for subsequent products offered may be increased to gain
confidence in the quality at the discretion of the Society.

2.3 When steel is not produced at the works at which it is rolled, a certificate is to be
supplied to the Surveyor at the rolling mill stating the process by which it was manufactured,
the name of the manufacturer who supplied it, the number of the cast from which it was made
and the ladle analysis. The Surveyor is to have access to the works at which the steel was
produced.

Note:

1. The attention of the users must be drawn to the fact that when fatigue loading is present, the
effective fatigue strength of a welded joint of higher strength steel may not be greater than that of
a welded joint in normal strength steels.
2. Before subjecting steels produced by thermo-mechanical rolling to further heating for forming or
stress relieving, or using high heat-input welding, special consideration must be given to the
possibility of a consequent reduction in mechanical properties.

3. Method of Manufacture

3.1 Steel is to be manufactured by the basic oxygen, electric furnace or open hearth
processes or by other processes specially approved by the Classification Society.

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W11 3.2 The deoxidation practice used for each grade is to comply with the appropriate
(cont) requirements of Tables 1 and 2.

3.3 The rolling practice applied for each grade is to comply with the appropriate condition
of supply of Tables 4 and 5.

The definitions of applicable rolling procedures and the schematic diagrams are given as
follows:

(i) As Rolled, AR
This procedure involves steel being cooled as it is rolled with no further heat treatment
the rolling of steel at high temperature followed by air cooling. The rolling and finishing
temperatures are typically in the austenite recrystallization region and above the
normalising temperature. The strength and toughness properties of steel produced by
this process are generally less than steel heat treated after rolling or than steel produced
by advanced processes.

(ii) Normalising, N
Normalising involves heating rolled steel above the critical temperature, Ac3, and in the
lower end of the austenite recrystallization region for a specific period of time, followed by
air cooling. The process improves the mechanical properties of as rolled steel by refining
the grain size and homogenising the microstructure.

(iii) Controlled Rolling, CR (Normalizing Rolling, NR):

A rolling procedure in which the final deformation is carried out in the normalising
temperature range, allowed to cool in air, resulting in a material condition generally
equivalent to that obtained by normalising.

(iv) Quenching and Tempering, QT

Quenching involves a heat treatment process in which steel is heated to an appropriate
temperature above the Ac3, held for a specific period of time, and then cooled with an
appropriate coolant for the purpose of hardening the microstructure. Tempering
subsequent to quenching is a process in which the steel is reheated to an appropriate
temperature not higher than the Ac1, maintained at that temperature for a specific period
of time to restore toughness properties by improving the microstructure and reduce the
residual stress caused by the quenching process.

(v) Thermo-Mechanical Rolling, TM (Thermo-Mechanical Controlled Processing, TMCP):

This is a procedure which involves the strict control of both the steel temperature and the
rolling reduction. Generally a high proportion of the rolling reduction is carried out close
to the Ar3 temperature and may involve the rolling in the dual phase temperature region.
Unlike controlled rolled (normalised rolling) the properties conferred by TM (TMCP)
cannot be reproduced by subsequent normalising or other heat treatment.

The use of accelerated cooling on completion of TM-rolling may also be accepted subject
to the special approval of the Society. The same applies for the use of tempering after
completion of the TM-rolling.

(vi) Accelerated Cooling, AcC

Accelerated cooling is a process, which aims to improve mechanical properties by
controlled cooling with rates higher than air cooling immediately after the final TM-rolling
operation. Direct quenching is excluded from accelerated cooling.

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The material properties conferred by TM and AcC cannot be reproduced by subsequent

W11 normalising or other heat treatment.
(cont) Where NR (CR) CR and TM with/without AcC are applied, the programmed rolling schedules
are to be verified by the Classification Society at the time of the steel works approval, and are
to be made available when required by the attending Surveyor. On the manufacturer’s
responsibility, the programmed rolling schedules are to be adhered to during the rolling
operation. Refer to the above 2.2. To this effect, the actual rolling records are to be reviewed
by the manufacturer and occasionally by the Surveyor.

When deviation from the programmed rolling schedules or normalizing or quenching and
tempering procedures occurs, the manufacturer shall take further measures required in the
above 2.2 to the Surveyor’s satisfaction.

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Schematic Diagrams of Thermo-Mechanical and Conventional Processes

W11
(cont)

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

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 W11

W11
(cont)

4. Chemical Composition

4.1 The chemical composition of samples taken from each ladle of each cast is to be
determined by the manufacturer in an adequately equipped and competently staffed
laboratory and is to comply with the appropriate requirements of Tables 1 and 2. For steel
plates and wide flats over 50 mm thick, slight deviations in the chemical composition may be
allowed as approved by the Classification Society.

4.2 The manufacturer's declared analysis will be accepted subject to occasional checks if
required by the Surveyor.

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Table 1 Chemical composition and deoxidation practice for normal strength steels
W11
(cont) Grade A B D E

Deoxidation Practice For t ≤ 50 mm For t ≤ 50 mm For t ≤ 25 mm Killed and fine

Any method Any method Killed grain treated
except rimmed except rimmed
steel (1)
For t > 50 mm For t > 50 mm For t > 25 mm
Killed Killed Killed and
fine grain
treated

Chemical Carbon plus 1/6 of the manganese content is not to exceed 0.40%
Composition % (4) (7) (8)
(ladle samples)
C max. 0.21 (2) 0.21 0.21 0.18
Mn min. 2.5 x C 0.80 (3) 0.60 0.70
Si max. 0.50 0.35 0.35 0.35
P max. 0.035 0.035 0.035 0.035
S max. 0.035 0.035 0.035 0.035
Al (acid soluble min) - - 0.015 (5) (6) 0.015 (6)

t = thickness

Notes:

1. Grade A sections up to a thickness of 12.5 mm may be accepted in rimmed steel subject to the
special approval of the Classification Society.
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 the Classification Society.
5. For Grade D steel over 25 mm thick.
6. For Grade D steel over 25 mm thick and Grade E steel the total aluminium content may be
determined instead of acid soluble content. In such cases the total aluminium content is to be not
less than 0.020%. A maximum aluminium content may also be specified by the Classification
Society. Other suitable grain refining elements may be used subject to the special approval of the
Classification Society.
7. The Classification Society may limit the amount of residual 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 indicated.

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Table 2 Chemical composition and deoxidation practice for higher strength steels
W11
(cont) Grade (1) A32 D32 E32 F32
A36 D36 E36 F36
A40 D40 E40 F40

Deoxidation Practice killed and fine grain treated

Chemical Composition % (5) (7)
(ladle samples)
C max. 0.18 0.16
Mn 0.90 – 1.60 (2) 0.90 – 1.60
Si max. 0.50 0.50
P max. 0.035 0.025
S max. 0.035 0.025
Al (acid soluble min) 0.015 (3) (4) 0.015 (3) (4)
Nb 0.02 – 0.05 (4) ) total: 0.02 – 0.05 (4) ) total:
V 0.05 – 0.10 (4) ) 0.12 0.05 – 0.10 (4) ) 0.12
Ti max. 0.02 ) max. 0.02 ) max.
Cu max. 0.35 0.35
Cr max. 0.20 0.20
Ni max. 0.40 0.80
Mo max. 0.08 0.08
N max. - 0.009 (0.012 if Al is present)
Carbon Equivalent (6)

Notes:

1. The letter “H” may be added either in front or behind the grade mark e.g. HA 32 or AH 32.
2. Up to a thickness of 12.5 mm the minimum manganese content may be reduced to 0.70%.
3. The total aluminium content may be determined instead of the acid soluble content. In such cases
the total aluminim content is to be not less than 0.020%.
4. 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.
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 the Classification
Society.
6. When required, the carbon equivalent value is to be calculated from the ladle analysis using the
following formula.
Mn Cr  Mo  V Ni  Cu
Ceq  C    (%)
6 5 15
This formula is applicable only to steels which are basically of the carbon-manganese type and
gives a general indication of the weldability of the steel.
7. Where additions of any other element have been made as part of the steelmaking practice, the
content is to be indicated.

4.3 For TM (TMCP) steels the following special requirements apply:

(i) The carbon equivalent value is to be calculated from the ladle analysis using the
following formula and to comply with the requirements of Table 3;
Mn Cr  Mo  V Ni  Cu
Ceq  C    (%)
6 5 15

(ii) The following formula (cold cracking susceptibility) may be used for evaluating weldability
instead of the carbon equivalent at the discretion of the Classification Society;

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 W11

Si Mn Cu Ni Cr Mo V
W11 Pcm  C  
30 20
    
20 60 20 15 10
 5B %

(cont)
In such cases the cold cracking susceptibility value required may be specified by the
Classification Society.

Table 3 Carbon equivalent for higher strength steels up to 100 mm in thickness

produced by TM

Grade Carbon Equivalent, max. (%) (1)

t ≤ 50 50 < t ≤ 100

A32, D32, E32, F32 0.36 0.38

A36, D36, E36, F36 0.38 0.40
A40, D40, E40, F40 0.40 0.42

t: thickness (mm)

Notes:

(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.

5. Condition of Supply

5.1 All materials are to be supplied in a condition complying with the appropriate
requirements of Tables 4 and 5.

Table 4 Condition of supply for normal strength steels (1)

Grades Thickness Condition of Supply

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

Notes:

(1) These conditions of supply and the impact test requirements are summarised in Table 8.
(2) Subject to the special approval of the Classification Society, Grades A and B steel plates may be
supplied in the as rolled condition - see 11.13.2 W11.14.2 (ii).
(3) Subject to the special approval of the Classification Society, 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. The frequency of impact tests is to be in accordance with W11.13.2
W11.14.2 (ii) and W11.13.3 W11.14.3 (iii) respectively.

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Table 5 Condition of supply for higher strength steels (1)

W11
(cont) 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 the Classification Society (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 the Classification Society (2)
or with Ti
Normalized, controlled rolled or thermo-
> 25 mm ≤ 100 mm
mechanically rolled (3)
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 9.
(2) The frequency of impact tests is to be in accordance with W11.13.2 W11.14.2 (ii).
(3) Subject to the special approval of the Classification Society, sections in Grades A32, A36, D32
and D36 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 E32 and E36
steels maybe supplied in the as rolled or controlled rolled condition. The frequency of impact tests
is to be in accordance with W11.13.2 W11.14.2 (ii) and W11.13.2 W11.14.2 (iii) respectively.
(4) Subject to the special approval of the Classification Society, sections in Grades F32 and F36
steels may be supplied in the controlled rolled condition. The frequency of impact tests is to be in
accordance with W11.13.3 W11.14.3 (iii).

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6. Mechanical Properties
W11
(cont) 6.1 For tensile test either the upper yield stress (ReH) or where ReH cannot be determined,
the 0.2 percent proof stress (Rp 0.2) is to be determined and the material is considered to
comply with the requirements if either value meets or exceeds the specified minimum value
for yield strength (Re).

6.2 The results obtained from tensile tests are to comply with the appropriate
requirements of Tables 6 and 7.

Table 6 Mechanical properties for normal strength steels

Impact Test
Yield
Tensile Average Impact Energy (J)
Strength Elongation
Strength Test min
Grade ReH (5.65 √S0)
Rm Temp.
(N/mm2) A5 (%) t ≤ 50 50 < t ≤ 70 70 < t ≤ 100
(N/mm2) °C
min
Long(3) Trans(3) Long(3) Trans(3) Long(3) Trans(3)
A +20 - - 34 (5) 24 (5) 41 (5) 27 (5)
B 400/520 0 27 (4) 20 (4) 34 24 41 27
235 (1) 22 (2)
D -20 27 20 34 24 41 27
E -40 27 20 34 24 41 27

t: thickness (mm)

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

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

≤5 ≤ 10 ≤ 15 ≤ 20 ≤ 25 ≤ 30 ≤ 40 ≤ 50

Elongation % 14 16 17 18 19 20 21 22

(3) See paragraph W11.6.3.

(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 the Society.

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Table 7 Mechanical properties for higher strength steels

W11
(cont) Yield
Impact Test
Tensile Average Impact Energy (J)
Strength Elongation
Strength Test min
Grade ReH (5.65 √S0)
Rm Temp.
(N/mm2) A5 (%) t ≤ 50 50 < t ≤ 70 70 < t ≤ 100
(N/mm2) °C
min
Long(2) Trans(2) Long(2) Trans(2) Long(2) Trans(2)
(3) (3)
A32 0 31 22 38 26 46 31
D32 -20 31 22 38 26 46 31
315 440/570 22 (1)
E32 -40 31 22 38 26 46 31
F32 -60 31 22 38 26 46 31
A36 0 34 (3) 24 (3) 41 27 50 34
D36 -20 34 24 41 27 50 34
355 490/630 21 (1)
E36 -40 34 24 41 27 50 34
F36 -60 34 24 41 27 50 34
A40 0 39 26 46 31 55 37
D40 -20 39 26 46 31 55 37
390 510/660 20 (1)
E40 -40 39 26 46 31 55 37
F40 -60 39 26 46 31 55 37

t: thickness (mm)

Notes:

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

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

(mm)
≤5 ≤ 10 ≤ 15 ≤ 20 ≤ 25 ≤ 30 ≤ 40 ≤ 50

Elongation A32, D32, E32 & F32 14 16 17 18 19 20 21 22

%
A36, D36, E36 & F36 13 15 16 17 18 19 20 21
A40, D40, E40 & F40 12 14 15 16 17 18 19 20

(2) See paragraph W11.6.3.

(3) For Grades A32 and A36 steels a relaxation in the number of impact tests for acceptance
purposes may be permitted by special agreement with the Classification Society provided that
satisfactory results are obtained from occasional check tests.

6.3 Minimum average energy values are specified for Charpy V-notch impact test
specimens taken in either the longitudinal or transverse directions (see W11.12.2 W11.13.2).
Generally only longitudinal test specimens need to be prepared and tested except for special
applications where transverse test specimens may be required by the purchaser or the
Classification Society. Transverse test results are to be guaranteed by the supplier.

The tabulated values are for standard specimens 10 mm x 10 mm. For plate thicknesses less
than 10 mm, impact test may be waived at the discretion of the Classification Society or sub-
size specimens, as specified in UR W2, may be used.

6.4 The average value obtained from one set of three impact tests is to comply with the
requirements given in Tables 6 and 7. One individual value only may be below the specified
average value provided it is not less than 70% of that value.

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6.5 Generally, impact tests are not required when the nominal plate thickness is less than
W11 6 mm.
(cont)
7. Surface quality Freedom from Defects

7.1 The steel is to be reasonably free from segregations and non-metallic inclusions. The
finished material is to have a workmanlike finish and is to be free from internal and surface
defects prejudicial to the use of the material for the intended application.

7.2 The acceptance criteria for surface finish and procedures for the repair of defects, as
detailed in Recommendation, No 12, "Guidance for the Surface Finish of Hot Rolled Steel
Plates and Wide Flats" are to be observed.

7.1 The steel is to be free from surface defects prejudicial to the use of the material for the
intended application.
The finished material is to have a surface quality in accordance with a recognized standard
such as EN 10163 parts 1, 2 and 3, or an equivalent standard accepted by the Classification
Society, unless otherwise specified in this section.

7.2 The responsibility for meeting the surface finish requirements rests with the
manufacturer of the material, who is to take the necessary manufacturing precautions and is
to inspect the products prior to delivery. At that stage, however, rolling or heat treatment scale
may conceal surface discontinuities and defects. If, during the subsequent descaling or
working operations, the material is found to be defective, the Classification Society may
require materials to be repaired or rejected.

7.2.1 The surface quality inspection method shall be in accordance with recognized national
or international standards agreed between purchaser and manufacturer, accepted by the
Classification Society.

7.2.2 If agreed by the manufacturer and purchaser, steel may be ordered with improved
surface finish over and above these requirements.

7.3 Acceptance Criteria

7.3.1 Imperfections

Imperfections of a harmless nature, for example pitting, rolled-in scale, indentations, roll
marks, scratches and grooves, regarded as being inherent of the manufacturing process, are
permissible irrespective of their number, provided the maximum permissible limits of Class A
of EN 10163-2 or limits specified in a recognized equivalent standard accepted by the
Classification Society, are not exceeded and the remaining plate or wide flat thickness
remains within the average allowable minus thickness tolerance specified in UR W13.
Total affected area with imperfection not exceeding the specified limits are not to exceed 15
% of the total surface in question.

7.3.2 Defects

Affected areas with imperfections with a depth exceeding the limits of Class A of EN 10163-2
or the maximum permissible limits specified in a recognized equivalent standard accepted by
the Classification Society, shall be repaired irrespective of their number.

Cracks, injurious surface flaws, shells (over lapping material with non-metallic inclusion),
sand patches, laminations and sharp edged seams (elongated defects) visually evident on

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 W11

surface and/or edge of plate are considered defects, which would impair the end use of the
W11 product and which require rejection or repair, irrespective of their size and number.
(cont)
7.4 Repair

7.4.1 Grinding repair

Grinding may be applied provided all the conditions below are adhered to:

(a) The nominal product thickness will not be reduced by more than 7% or 3 mm,
whichever is the less.

(b) Each single ground area does not exceed 0,25 m2.

(c) All ground areas do not exceed 2% of the total surface in question.

(d) Ground areas lying in a distance less than their average breadth to each other are to be
regarded as one single area.

(e) Ground areas lying opposite each other on both surfaces shall not decrease the product
thickness by values exceeding the limits as stated under (a).

Defects or unacceptable imperfections are to be completely removed by grinding and the

remaining plate or wide flat thickness shall remain within the average allowable minus
thickness tolerance specified in UR W13. The ground areas shall be a smooth transition to
the surrounding surface of the product. Complete elimination of the defect is to be verified by
magnetic particle or by liquid penetrant testing.

7.4.2 Welding repair

Weld repair procedures and the method are to be reported and be approved by the
Classification Societies. Repair of defects such as unacceptable imperfections, cracks, shells
or seams shall be followed by magnetic particle or liquid penetrant testing.

Local defects which cannot be repaired by grinding as stated in 7.4.1 may be repaired by
welding with the agreement of the Classification Society subject to the following conditions:

(a) Any single welded area shall not exceed 0,125 m2 and the sum of all areas shall not
exceed 2% of the surface side in question.

(b) The distance between two welded areas shall not be less than their average width.

(c) The weld preparation shall not reduce the thickness of the product below 80% of the
nominal thickness. For occasional defects with depths exceeding the 80% limit, special
consideration at the Surveyor’s discretion will be necessary.

(d) If weld repair depth exceeds 3 mm, UT may be requested by the Classification Society.
If required, UT shall be carried out in accordance with an approved procedure.

(e) The repair shall be carried out by qualified welders using an approved procedure for the
appropriate steel grade. The electrodes shall be of low hydrogen type and shall be dried
in accordance with the manufacturer’s requirements and protected against
rehumidification before and during welding.

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7.5 The surface quality and condition requirement herein are not applied to products in
W11 forms of bars and tubulars, which will be subject to manufacturers’ conformance standards.
(cont)
8. Internal soundness

8.1 If plates and wide flats are ordered with ultrasonic inspection, this is to be made in
accordance with an accepted standard at the discretion of the Classification Society.

8.2 Verification of internal soundness is the responsibility of the manufacturer. The

acceptance of internal soundness by the Classification Society’s surveyor shall not absolve
the manufacturer from this responsibility.

89. Tolerances

8.19.1 Unless otherwise agreed or specially required the thickness tolerances in Unified
Requirement W13 "Allowable under thickness Thickness tolerances of steel plates and wide
flats" are applicable.

910. Identification of Materials

9.110.1The steelmaker is to adopt a system for the identification of ingots, slabs and finished
pieces which will enable the material to be traced to its original cast.

9.210.2The Surveyor is to be given full facilities for so tracing the material when required.

1011. Testing and Inspection

10.111.1Facilities for Inspection

The manufacturer is to afford the Surveyor all necessary facilities and access to all relevant
parts of the works to enable him to verify that the approved process is adhered to, for the
selection of test materials, and the witnessing of tests, as required by the Rules, and for
verifying the accuracy of the testing equipment.

10.211.2Testing Procedures

The prescribed tests and inspections are to be carried out at the place of manufacture before
dispatch. The test specimens and procedures are to be in accordance with Unified
Requirement W2 “Test Specimens and Mechanical Testing Procedures for Materials”. All the
test specimens are to be selected and stamped by the Surveyor and tested in his presence,
unless otherwise agreed.

10.311.3Through Thickness Tensile Tests

If plates and wide flats with thickness of 15 mm and over are ordered with through thickness
properties, the through thickness tensile test in accordance with Unified Requirement W14
“Steel Plates and Wide Flats with specified minimum with Improved Through Thickness
Properties (“Z” quality)” is to be carried out.

10.4 Ultrasonic Inspection

If plates and wide flats are ordered with ultrasonic inspection, this is to be made in
accordance with an accepted standard at the discretion of the Classification Society.

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10.511.4Surface Inspection and Dimensions

W11
(cont) Surface inspection and verification Verification of dimensions are the responsibility of the
steel maker. The acceptance by the Classification Society’s Surveyor shall not absolve the
steel maker from this responsibility.

1112. Test Material

11.112.1Definitions

(a) Piece: the term "piece" is understood to mean the rolled product from a single slab, billet
or ingot if this is rolled directly into plates, sections or bars.

(b) Batch: a number of similar pieces presented as a group for acceptance tests.

11.212.2Test Samples

(a) All material in a batch presented for acceptance tests is to be of the same product form
e.g. plates, flats, sections, etc. from the same cast and in the same condition of supply.

(b) The test samples are to be fully representative of the material and, where appropriate,
are not to be cut from the material until heat treatment has been completed.

(c) The test specimens are not to be separately heat treated in any way.

(d) Unless otherwise agreed the test samples are to be taken from the following positions:

(i) Plates and flats with a width ≥ 600 mm. The test samples are to be taken from one
end at a position approximately midway between the axis in the direction of the
rolling and the edge of the rolled product (see Fig. 1). Unless otherwise agreed the
tensile test specimens are to be prepared with their longitudinal axes transverse to
the final direction of rolling.

(ii) Flats with a width < 600 mm, bulb flats and other sections. The test samples are to
be taken from one end at a position approximately one third from the outer edge (see
Figs. 2, 3 and 4) or in the case of small sections, as near as possible to this position.
In the case of channels, beams or bulb angles, the test samples may alternatively be
taken from a position approximately one quarter of the width from the web centre line
or axis (see Fig. 3). The tensile test specimens may be prepared with their
longitudinal axes either parallel or transverse to the final direction of rolling.

(iii) Bars and other similar products. The test samples are to be taken so that the
longitudinal axes of the test specimens are parallel to the direction of rolling and are
as near as possible to the following
– for non-cylindrical sections, at one third of the half diagonal from the outside,
– for cylindrical sections, at one third of the radius from the outside (see Fig. 6).

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W11
(cont)

1213. Mechanical Test specimens

12.113.1Tensile Test Specimens. The dimensions of the tensil test specimens are to be in
accordance with Unified Requirement, W2. Generally for plates, wide flats and sections flat
test specimens of full product thickness are to be used. Round test specimens may be used
when the product thickness exceeds 40 mm or for bards and other similar products.
Alternatively for small sizes of bars, etc. test specimens may consist of a suitable length of
the full cross section of the product.

12.213.2 Impact Test Specimens. The impact test specimens are to be of the Charpy V-notch
type cut with their edge within 2 mm from the “as rolled” surface with their longitudinal axes
either parallel (indicated “Long” in Table 6 & 7) or transverse (indicated "Trans" in Tables 6 &
7) to the final direction of rolling of the material. The notch is to be cut in a face of the test
specimen 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 edge (see also W11.6.3). Where the
product thickness exceeds 40 mm, the impact test specimens are to be taken with their
longitudinal axis at a quarter thickness position.

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1314. Number of Test Specimens

W11
(cont) 13.114.1Number of Tensile Tests. For each batch presented, except where specially agreed
by the Classification Society, one tensile test is to be made from one piece unless the weight
of finished material is greater than 50 tonnes or fraction thereof. Additionally tests are to be
made for every variation of 10 mm in the thickness or diameter of products from the same
cast.

13.214.2Number of Impact Tests (except for Grades E, E32, E36, E40, F32, F36 and F40),
see Tables 8 & 9.

(i) Except where otherwise specified or specially agreed by the Classification Society, for
each batch presented, at least one set of three Charpy V-notch test specimens is to be
made from one piece unless the weight of finished material is greater than 50 tonnes, in
which case one extra set of three test specimens is to be made from a different piece
from each 50 tonnes or fraction thereof. When steel plates except for Grade A steel over
50 mm in thickness is supplied in the controlled rolled condition, the frequency of impact
test is to be made from a different piece from each 25 tonnes or fraction thereof.

(ii) For steel plates of Grades A40 and D40 with thickness over 50 mm in normalized or TM
condition, one set of impact test specimens is to be taken from each batch of 50 tonnes
or fraction thereof. For those in QT condition, one set of impact test specimens is to be
taken from each length as heat treated.

(iii) When, subject to the special approval of the Classification Society, material is supplied in
the as rolled condition, the frequency of impact tests is to be increased to one set from
each batch of 25 tonnes or fraction thereof. Similarly Grade A steel over 50 mm in
thickness may be supplied in the as rolled condition. In such case one set of three
Charpy V-notch test specimens is to be taken from each batch of 50 tonnes or fraction
thereof.

(iv) The piece selected for the preparation of the test specimens is to be the thickest in each
batch.

13.314.3Number of Impact Tests (Grades E, E32, E36, E40, F32, F36 and F40).

(i) For steel plates supplied in the normalised or TM condition one set of impact test
specimens is to be taken from each piece. For quenched and tempered steel plates one
set of impact test specimens is to be taken from each length as heat treated.

(ii) For sections one set of impact tests is to be taken from each batch of 25 tonnes or
fraction thereof.

(iii) When, subject to the special approval of the Classification Society, sections other than
Grades E40 and F40 are supplied in the as rolled or controlled rolled condition, one set
of impact tests is to be taken from each batch of 15 tonnes or fraction thereof.

(iv) For (ii) and (iii) above the piece selected for the preparation of the test specimens is to be
the thickest in each batch.

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1415. Retest Procedures

W11
(cont) 14.115.1When the tensile test from the first piece selected in accordance with W11.13.1
W11.14.1 fails to meet the requirements re-test requirements for tensile tests are to be in
accordance with UR W2.

14.215.2If one or both of the additional tests referred to above are unsatisfactory, the piece is
to be rejected, but the remaining material from the same batch may be accepted provided
that two of the remaining pieces in the batch selected in the same way, are tested with
satisfactory results. If unsatisfactory results are obtained from either of these two pieces then
the batch of material is to be rejected.

14.315.3Re-test requirements for Charpy impact tests are to be in accordance with UR W2.

14.415.4When the initial piece, representing a batch, gives unsatisfactory results from the
additional Charpy V-notch impact tests referred to above, this piece is to be rejected but the
remaining material in the batch may be accepted provided that two of the remaining pieces in
the batch are tested with satisfactory results. If unsatisfactory results are obtained from either
of these two pieces then the batch of material is to be rejected. The pieces selected for these
additional tests are to be the thickest remaining in the batch.

14.515.5If any test specimen fails because of faulty preparation, visible defects or (in the
case of tensile test) because of fracturing outside the range permitted for the appropriate
gauge length, the defective test piece may, at the Surveyors discretion, be disregarded and
replayed by an additional test piece of the same type.

14.615.6At the option of the steelmaker, when a batch of material is rejected, the remaining
pieces in the batch may be resubmitted individually for test and those pieces which give
satisfactory results may be accepted.

14.715.7At the option of the steelmaker, rejected material may be resubmitted after heat
treatment or reheat treatment, or may be resubmitted as another grade of steel and may then
be accepted provided the required tests are satisfactory.

14.815.8In the event of any material proving unsatisfactory during subsequent working or
fabrication, such material may be rejected, notwithstanding any previous satisfactory testing
and/or certification.

1516. Branding

15.116.1Every finished piece is to be clearly marked by the maker in at least one place with
the Classification Society's brand and the following particulars:

(i) Unified identification mark for the grade steel (e.g. A, A36).
(ii) Steels which have been specially approved by the Classification Society and which differ
from these requirements (see W11.1.4) are to have the letter "S" after the above
identification mark (e.g. A36S, ES).
(iii) When required by the Classification Society, material supplied in the thermo-
mechanically controlled process condition is to have the letters TM added after the
identification mark (e.g. E36 TM).
(iv) Name or initials to identify the steelworks.
(v) Cast or other number to identify the piece.
(vi) If required by the purchaser, his order number or other identification mark.

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15.216.2 Steel plates that have complied with the requirements for corrosion resistant
W11 steel will be identified by adding a corrosion designation to the unified identification mark for
(cont) the grade of steel.

The corrosion resistant steel is to be designated according to its area of application as

follows:

- Lower surface of strength deck and surrounding structures; RCU

- Upper surface of inner bottom plating and surrounding structures; RCB
- For both strength deck and inner bottom plating; RCW

Example of designation:

A36 TM RCB Z35

15.316.3The above particulars, but excluding the manufacturer's name or trade mark where
this is embossed on finished products are to be encircled with paint or otherwise marked so
as to be easily recognisable.

15.416.4Where a number of light materials are securely fastened together in bundles the
manufacturer may, subject to the agreement of the Classification Society, brand only the top
piece of each bundle, or alternatively, a firmly fastened durable label containing the brand
may be attached to each bundle.

15.516.5In the event of any material bearing the Classification Society's brand failing to
comply with the test requirements, the brand is to be unmistakably defaced by the
manufacturer.

1617. Documentation

16.117.1The Surveyor is to be supplied with the number of copies as required by the

Classification Society, of the test certificates or shipping statements for all accepted
materials. The Classification Society may require separate documents of each grade of steel.
These documents are to contain, in addition to the description, dimensions, etc., of the
material, at least the following particulars:

(i) Purchaser's order number and if known the hull number for which the material is
intended.
(ii) Identification of the cast and piece including, where appropriate, the test specimen
number.
(iii) Identification of the steelworks.
(iv) Identification of the grade of steel.
(v) Ladle analysis (for elements specified in Tables 1 & 2).
(vi) For steel with a corrosion resistant steel designation the weight percentage of each
element added or intentionally controlled for improving corrosion resistance.
(vii) Condition of supply when other than as rolled i.e. normalised, controlled rolled or
thermomechanically rolled.
(viii) State if rimming steel has been supplied for grade A sections, up to 12.5 mm thick.
(ix) Test Results

16.217.2Before the test certificates or shipping statements are signed by the Surveyor, the
manufacturer is required to furnish him with a written declaration stating that the material has
been made by an approved process and that it has been subjected to and has withstood
satisfactory the required tests in the presence of the Surveyor or his authorized deputy. The
name of the Classification Society is to appear on the test certificate. The following form of

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declaration will be accepted if stamped or printed on each test certificate or shipping

W11 statement with the name of the steelworks and initialled for the makers by an authorized
(cont) official:

"We hereby certify that the material has been made by an approved process and has been
satisfactorily tested in accordance with the Rules of the Classification Society."

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Table 8 Required condition of supply and number of impact tests for normal
W11 strength steels
(cont)

Remarks:

1. Condition of Supply
A – Any
N – Normalised Condition
CR – Controlled Rolled Condition
TM – Thermo-Mechanical rolling
AR* – As Rolled Condition subject to special approval of the Classification Society
CR* – Controlled Rolled Condition subject to special approval of the Classification Society
2. Number of Impact Tests
One set of impact tests is to be taken from each batch of the "specified weight" in ( ) or fraction
thereof.
3. See Note (5) of Table 6.

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Table 9 Required condition of supply and number of impact tests for higher
W11 strength steels
(cont)

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W11
(cont)

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Table 9 Required condition of supply and number of impact tests for higher
W11 strength steels (cont’d)
(cont)

Remarks:

(1) Condition of Supply

A - Any
N - Normalized Condition
CR - Controlled Rolled Condition
TM - Thermo-Mechanical Rolling
QT - Quenched and Tempered Condition
AR* - As Rolled Condition subject to the special approval of the Classification Society
CR* - Controlled Rolled Condition subject to the special approval of the Classification Society
(2) Number of Impact Tests
One set of impact tests is to be taken from each batch of the “specified weight” in ( ) or fraction
thereof.
For grades A32 and A36 steels a relaxation in the number of impact tests may be permitted. (See
Note(3) of Table 7.)

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Appendix A. Manufacturing Approval Scheme of Hull Structural Steels

W11
(cont)
A1. Manufacturing Approval Scheme of Semi Finished Products for Hull Structural
Steels

1. Scope of application

This document specifies, as given in W11.2.1, the scheme for the approval of the
manufacturing process of semi-finished products such as ingots, slabs, blooms and billets for
the structural steels.

The manufacturing approval scheme is valid for verifying the manufacturer’s capability to
provide satisfactory products stably under effective process and production controls in which
is required in W11.2.2.

2. Approval application

2.1 Documents to be submitted

The manufacturer has to submit to the Society, request of approval, proposed approval test
program (see 3.1) and general information relevant to:

a) Name and site address of the manufacturer, location of the workshops, general
indications relevant to the background, dimension of the works, estimated total annual
production of finished products for shipbuilding and for other applications, as deemed
useful.

b) Organization and quality:

 organizational chart
 staff employed
 staff employed and organization of the quality control department
 qualification of the personnel involved in activities related to the quality of the products
 certification of compliance of the quality system with IS0 9001 or 9002, if any
 approval certificates already granted by other Classification Societies, if any

c) Manufacturing facilities
 flow chart of the manufacturing process
 origin and storage of raw materials
 storage of finished products
 equipment for systematic control during fabrication

d) Details of inspections and quality control facilities

 details of system used for identification of materials at the different stages of
manufacturing
 equipment for chemical analyses and relevant calibration procedures
 list of quality control procedures

e) Type of products (ingots, slabs, blooms, billets); types of steel (normal or higher
strength), range of thickness and aim material properties as follows:
 range of chemical composition and aim analyses, including grain refining, micro
alloying and residual elements, for the various grades of steel; if the range of chemical

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composition depends on thickness and supply condition, the different ranges are to be
W11 specified, as appropriate
(cont)  aim maximum carbon equivalent according to IIW formula
 aim maximum Pcm content for higher strength grades with low carbon content C <
0.13 %
 production statistics of the chemical composition and, if available at rolling mills,
mechanical properties (ReH, Rm, A% and KV). The statistics are intended to
demonstrate the capability to manufacture the steel products in accordance with the
requirements.

f) Steelmaking
 steel making process and capacity of furnace/s or converter/s
 raw material used
 deoxidation and alloying practice
 desulphurisation and vacuum degassing installations, if any
 casting methods: ingot or continuous casting. In the case of continuous casting,
information relevant to type of casting machine, teeming practice, methods to prevent
re-oxidation, inclusions and segregation control, presence of electromagnetic stirring,
soft reduction, etc., is to be provided as appropriate.
 ingot or slab size and weight
 ingot or slab treatment: scarfing and discarding procedures

g) Approval already granted by other Classification Societies and documentation of

approval tests performed.

2.2 Documents to be submitted for changing the approval conditions

The manufacturer has to submit to the Society the documents required in 2.1 together with
the request of changing the approval conditions, in the case of the following a) through c):

a) Change of the manufacturing process (steel making process, casting method, steel
making plant, caster)
b) Change of the thickness range (dimension)
c) Change of the chemical composition, added element, etc.

However, where the documents are duplicated by the ones at the previous approval for the
same type of product, part or all of the documents may be omitted except the approval test
program (see 3.1).

3. Approval tests

3.1 Extent of the approval tests

The extent of the test program is specified in 3.6, it may be modified on the basis of the
preliminary information submitted by the manufacturer.

In particular a reduction of the indicated number of casts, product thicknesses and types to be
tested or complete suppression of the approval tests may be accepted by the Society taking
into account:

a) Approval already granted by other Classification Societies and documentation of

approval tests performed.

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b) Types of steel to be approved and availability of long term statistic results of chemical
W11 properties and of mechanical tests performed on rolled products.
(cont) c) Change of the approval conditions.

On the other hand, an increase of the number of casts and thicknesses to be tested may be
required in the case of newly developed types of steel or manufacturing processes.

3.2 Approval test program

Where the number of tests differs from those shown in 3.6, the program is to be confirmed by
the Society before the tests are carried out.

3.3 Approval survey

The approval tests are to be witnessed by the Surveyor at the manufacturer’s plant and the
execution of the plant inspection in operation may be required by the Surveyor during the visit
for the approval.

If the testing facilities are not available at the works, the tests are to be carried out at
recognized laboratories.

3.4 Selection of the test product

For each type of steel and for each manufacturing process (e.g. steel making, casting), one
test product with the maximum thickness and one test product with the minimum thickness to
be approved are in general to be selected for each kind of product (ingots, slabs,
blooms/billets).

The selection of the casts for the test product is to be based on the typical chemical
composition, with particular regard to the specified Ceq or Pcm values and grain refining
micro-alloying additions.

3.5 Position of the test samples

The test samples are to be taken, unless otherwise agreed, from the product (slabs, blooms,
billets) corresponding to the top of the ingot, or, in the case of continuous casting, a random
sample.

3.6 Tests on base material

3.6.1 Type of tests

The tests to be carried out for the approval of the manufacturing process of semi-finished
products are:

- Chemical analysis. The analysis is to be complete and is to include micro alloying

elements.
- Sulphur prints.

In addition, for initial approval and for any upgrade of the approval, the Society will require full
tests indicated in Appendix A2.3 to be performed at rolling mill on the minimum thickness
semi finished product.

In case of a multi-caster work, full tests on finished products shall be carried out for one
caster and reduced tests (chemical analysis and sulphur print) for the others. The selection of

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the caster shall be based on the technical characteristics of the casters to be evaluated on
W11 case by case basis to be performed at rolling mill on products manufactured from the
(cont) minimum thickness semi finished product.

3.6.2 Test specimens and testing procedure

The following tests and procedures apply:

a) Chemical analyses
Both the ladle and product analyses are to be reported. In general the content of the
following elements is to be checked: C, Mn, Si, P, S, Ni, Cr, Mo, Al, N, Nb, V, Cu, As, Sn,
Ti and, for steel manufactured from electric or open-hearth furnace, Sb and B.

b) Sulphur prints are to be taken from product edges which are perpendicular to the axis of
the ingot or slab. These sulphur prints are to be approximately 600 mm long taken from
the centre of the edge selected, i.e. on the ingot centreline, and are to include the full
product thickness.

4. Results

All the results, which are in any case to comply with the requirements of the Rules, are
evaluated for the approval; depending on the results, particular limitations or testing
conditions, as deemed appropriate, may be specified in the approval document.

All the information required under Appendix A2.2, applicable to the products submitted to the
tests, is to be collected by the manufacturer and put in the dossier which will include all the
results of the tests and operation records relevant to steel making, casting and, when
applicable, rolling and heat treatment of the test products.

5. Certification

5.1 Approval

Upon satisfactory completion of the survey, approval is granted by the Society.

On the approval certificate the following information is to be stated:

 Type of products (ingots, slabs, blooms, billets)

 Steelmaking and casting processes
 Thickness range of the semi-finished products
 Types of steel (normal or higher strength)

It is also to be indicated that the individual users of the semi finished products are to be
approved for the manufacturing process of the specific grade of rolled steel products they are
going to manufacture with those semi finished products.

5.2 List of approved manufacturers

The approved manufacturers are entered in a list containing the types of steel and the main
conditions of approval.

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6. Renewal of approval
W11
(cont) The validity of the approval is to be a maximum of five years.

Renewal can be carried out by an audit and assessment on the result of satisfactory survey
during the period*. Where for operational reasons, the renewal audit falls outside the period
of approval, the manufacturer will still be considered as approved if agreement to this audit
date is made within the original period of approval, in this instance if successful, the extension
of approval will be back dated to the original renewal date.

Manufacturers who have not produced the approved grades and products during the period
between renewals may be required to either carry out approval tests or, on the basis of
results of production of similar grades of products, at the discretion of the Society, be re-
approved.

7. Reconsideration of the approval

During the period of validity the approval may be reconsidered in the following cases:

a) in service failures, traceable to product quality

b) non conformity of the product revealed during fabrication and construction

c) discovered failure of the Manufacturer’s quality system

d) changes brought by the Manufacturer, without preliminary agreement of the Society, to

the extent of the approval defined at the time of the approval

e) evidence of major non conformities during testing of the products.

* The provision for renewal of approval is also to be applied to all grades and products which were
approved by the Society prior to an implementation of revision 4 of this UR W 11 regardless of the
validity of certificate in existing approvals. Such renewal is to be completed within five years after the
revision 4 becomes effective.

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A2. Manufacturing Approval Scheme of Hull Structural Steels

W11
(cont)
1. Scope of application

This document specifies, as given in W11.2.1, the scheme for the approval of the
manufacturing process of normal and higher strength hull structural steels.

The manufacturing approval scheme is valid for verifying the manufacturer’s capability to
provide satisfactory products stably under effective process and production controls in
operation including programmed rolling, which is required in W11.2.2 and W11.3.3.

2. Approval application

2.1 Documents to be submitted

The manufacturer has to submit to the Society, request of approval, proposed approval test
program (see 3.1) and general information relevant to:

a) Name and site address of the manufacturer, location of the workshops, general
indications relevant to the background, dimension of the works, estimated total annual
production of finished products for shipbuilding and for other applications, as deemed
useful.

b) Organization and quality:

 organizational chart
 staff employed
 staff employed and organization of the quality control department
 qualification of the personnel involved in activities related to the quality of the products
 certification of compliance of the quality system with IS0 9001 or 9002, if any
 approval certificates already granted by other Classification Societies, if any

c) Manufacturing facilities
 flow chart of the manufacturing process
 origin and storage of raw materials
 storage of finished products
 equipment for systematic control during fabrication

d) Details of inspections and quality control facilities

 details of system used for identification of materials at the different stages of
manufacturing
 equipment for mechanical tests, chemical analyses and metallography and relevant
calibration procedures
 equipment for non destructive examinations
 list of quality control procedures

e) Type of products (plates, sections, coils), grades of steel, range of thickness and aim
material properties as follows:
 range of chemical composition and aim analyses, including grain refining, micro
alloying and residual elements, for the various grades of steel; if the range of chemical
composition depends on thickness and supply condition, the different ranges are to be
specified, as appropriate
 aim maximum carbon equivalent according to IIW formula

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 aim maximum Pcm content for higher strength grades with low carbon content C <
W11 0.13 %
(cont)  production statistics of the chemical composition and mechanical properties (ReH,
Rm, A% and KV). The statistics are intended to demonstrate the capability to
manufacture the steel products in accordance with the requirements.

f) Steelmaking
 steel making process and capacity of furnace/s or converter/s
 raw material used
 deoxidation and alloying practice
 desulphurisation and vacuum degassing installations, if any
 casting methods: ingot or continuous casting. In the case of continuous casting,
information relevant to type of casting machine, teeming practice, methods to prevent
re-oxidation, inclusions and segregation control, presence of electromagnetic stirring,
soft reduction, etc., is to be provided as appropriate.
 ingot or slab size and weight
 ingot or slab treatment: scarfing and discarding procedures

g) Reheating and rolling

 type of furnace and treatment parameters
 rolling: reduction ratio of slab/bloom/billet to finished product thickness, rolling and
finishing temperatures
 descaling treatment during rolling
 capacity of the rolling stands

h) Heat treatment
 type of furnaces, heat treatment parameters and their relevant records
 accuracy and calibration of temperature control devices

i) Programmed rolling
For products delivered in the controlled rolling(CR) or thermo-mechanical rolling (TM)
condition, the following additional information on the programmed rolling schedules is to
be given:
 description of the rolling process
 normalizing temperature, re-crystallization temperature and Ar3 temperature and the
methods used to determine them
 control standards for typical rolling parameters used for the different thickness and
grades of steel (temperature and thickness at the beginning and at the end of the
passes, interval between passes, reduction ratio, temperature range and cooling
speed of accelerated cooling, if any) and relevant method of control
 calibration of the control equipment

j) Recommendations for working and welding in particular for products delivered in the CR
or TM condition
 cold and hot working recommendations if needed in addition to the normal practice
used in the shipyards and workshops
 minimum and maximum heat input if different from the ones usually used in the
shipyards and workshops (15 - 50 kJ/cm)

k) Where any part of the manufacturing process is assigned to other companies or other
manufacturing plants, additional information required by the Society is to be included.

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l) Approval already granted by other Classification Societies and documentation of

W11 approval tests performed.
(cont)
2.2 Documents to be submitted for changing the approval conditions

The manufacturer has to submit to the Society the documents required in 2.1 together with
the request of changing the approval conditions, in the case of the following a) through e) as
applicable:

a) Change of the manufacturing process (steel making, casting, rolling and heat treatment)
b) Change of the maximum thickness (dimension)
c) Change of the chemical composition, added element, etc.
d) Subcontracting the rolling, heat treatment, etc.
e) Use of the slabs, blooms and billets manufactured by companies other than the ones
verified in the approval tests.

However, where the documents are duplicated by the ones at the previous approval for the
same type of product, part or all of the documents may be omitted except the approval test
program (see 3.1).

3. Approval tests

3.1 Extent of the approval tests

The extent of the test program is specified in 3.6 and 3.7; it may be modified on the basis of
the preliminary information submitted by the manufacturer.

In particular a reduction of the indicated number of casts, steel plate thicknesses and grades
to be tested or complete suppression of the approval tests may be accepted by the Society
taking into account:

a) Approval already granted by other Classification Societies and documentation of

approval tests performed
b) Grades of steel to be approved and availability of long term statistic results of chemical
and mechanical properties
c) Approval for any grade of steel also covers approval for any lower grade in the same
strength level, provided that the aim analyses, method of manufacture and condition of
supply are similar.
d) For higher tensile steels, approval of one strength level covers the approval of the
strength level immediately below, provided the steelmaking process, deoxidation and fine
grain practice, casting method and condition of supply are the same.
e) Change of the approval conditions

On the other hand, an increase of the number of casts and thicknesses to be tested may be
required in the case of newly developed types of steel or manufacturing processes.

In case of multi-source slabs or changing of slab manufacturer, the rolled steel manufacturer
is required to obtain the approval of the manufacturing process of rolled steels using the slabs
from each slab manufacturer and to conduct approval tests in accordance with 3.6 and 3.7. A
reduction or complete suppression of the approval tests may considered by the Society taking
into account previous approval as follows:

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 the rolled steel manufacturer has already been approved for the manufacturing
W11 process using other semi finished products characterized by the same thickness, steel
(cont) grade, grain refining and micro-alloying elements, steel making and casting process;
 the semi finished products manufacturer has been approved for the complete
manufacturing process with the same conditions (steelmaking, casting, rolling and
heat treatment) for the same steel types.

3.2 Approval test program

Where the number of tests differs from those shown in 3.6 and 3.7, the program is to be
confirmed by the Society before the tests are carried out.

3.3 Approval survey

The approval tests are to be witnessed by the Surveyor at the manufacturer’s plant and the
execution of the plant inspection in operation may be required by the Surveyor during the visit
for the approval.

If the testing facilities are not available at the works, the tests are to be carried out at
recognised laboratories.

3.4 Selection of the test product

For each grade of steel and for each manufacturing process (e.g. steel making, casting,
rolling and condition of supply), one test product with the maximum thickness (dimension) to
be approved is in general to be selected for each kind of product.

In addition, for initial approval, the Society will require selection of one test product of average
thickness.

The selection of the casts for the test product is to be based on the typical chemical
composition, with particular regard to the specified Ceq or Pcm values and grain refining
micro-alloying additions.

3.5 Position of the test samples

The test samples are to be taken, unless otherwise agreed, from the product (plate, flat,
section, bar) corresponding to the top of the ingot, or, in the case of continuous casting, a
random sample.

The position of the samples to be taken in the length of the rolled product, "piece" defined in
W11.11.1 W11.12.1 (a), (top and/or bottom of the piece) and the direction of the test
specimens with respect to the final direction of rolling of the material are indicated in Table 1.

The position of the samples in the width of the product is to be in compliance with W11.11.2
W11.12.2 (d).

3.6 Tests on base material

3.6.1 Type of tests

The tests to be carried out are indicated in the following Table 1.

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Table 1 Tests on base material

W11
(cont) Position of the samples and
Type of test Remarks
direction of the test specimens (1)
ReH, Rm, A5(%), RA(%) are to be
Tensile test Top and bottom transverse (2)
reported
Tensile test (stress relieved) Stress relieving at 600 °C
Top and bottom transverse (2)
only for TM steels (2 min/mm with minimum 1 hour)
Impact tests (3) on non aged
Testing temperature (°C)
specimens for grades:
A, B, A32, A36, A40 +20 0 -20
D, D32, D36, D40 0 -20 -40
Top and bottom - longitudinal
E, E32, E36, E40 0 -20 -40 -60
F32, F36, F40 -20 -40 -60 -80
A, B, A32, A36, A40 +20 0 -20
D, D32, D36, D40 0 -20 -40
Top - transverse (4)
E, E32, E36, E40 -20 -40 -60
F32, F36, F40 -40 -60 -80
Impact test (3) on strain aged
Testing temperature (°C)
specimens (5) for grades:
A32, A36, A40 +20 0 -20
D, D32, D36, D40 0 -20 -40
Top - longitudinal
E, E32, E36, E40 -20 -40 -60
F32, F36, F40 -40 -60 -80
Complete analyses including micro
Chemical analyses (6) Top
alloying elements
Sulphur prints Top
Micro examination Top
Grain size determination Top only for fine grain steels
only for grades E, E32, E36, E40,
Drop weight test (4) Top
F32, F36, F40
Through thickness tensile only for grades with improved
Top and bottom
tests through thickness properties

1) For hot rolled strips see 3.6.2.

2) Longitudinal direction for sections and plates having width less than 600 mm.
3) One set of 3 Charpy V-notch impact specimens is required for each impact test.
4) Not required for sections and plates having width less than 600 mm.
5) Deformation 5% + 1 hour at 250°C.
6) Besides product analyses, ladle analyses are required.

3.6.2 Test specimens and testing procedure

The test specimens and testing procedures are to be, as a rule, in accordance with W2.

In particular the following applies:

a) Tensile test
 for plates made from hot rolled strip one additional tensile specimen is to be taken
from the middle of the strip constituting the coil.
 for plates having thickness higher than 40 mm, when the capacity of the available
testing machine is insufficient to allow the use of test specimens of full thickness,
multiple flat specimens, representing collectively the full thickness, can be used.

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Alternatively two round specimens with the axis located at one quarter and at mid-
W11 thickness can be taken.
(cont) b) Impact test
 for plates made from hot rolled strip one additional set of impact specimens is to be
taken from the middle of the strip constituting the coil.
 for plates having thickness higher than 40 mm one additional set of impact specimens
is to be taken with the axis located at mid-thickness.
 in addition to the determination of the energy value, also the lateral expansion and the
percentage crystallinity are to be reported.

c) Chemical analyses
Both the ladle and product analyses are to be reported. The material for the product
analyses should be taken from the tensile test specimen. In general the content of the
following elements is to be checked: C, Mn, Si, P, S, Ni, Cr, Mo, Al, N, Nb, V, Cu, As, Sn,
Ti and, for steel manufactured from electric or open-hearth furnace, Sb and B.

d) Sulphur prints are to be taken from plate edges which are perpendicular to the axis of the
ingot or slab. These sulphur prints are to be approximately 600 mm long taken from the
centre of the edge selected, i.e. on the ingot centreline, and are to include the full plate
thickness.

e) Micrographic examination: the micrographs are to be representative of the full thickness.

For thick products in general at least three examinations are to be made at surface, one
quarter and mid-thickness of the product.

All photomicrographs are to be taken at x100 magnification and where ferrite grain size
exceeds ASTM 10, additionally at x500 magnification. Ferrite grain size should be
determined for each photomicrograph.

f) Drop weight test: the test is to be performed in accordance with ASTM E208. The NDTT
is to be determined and photographs of the tested specimens are to be taken and
enclosed with the test report.

g) Through thickness tensile test: the test is to be performed in accordance with W14.
The test results are to be in accordance, where applicable, with the requirements
specified for the different steel grades in W11.

3.6.3 Other tests

Additional tests such as CTOD test, large scale brittle fracture tests (Double Tension test,
ESSO test, Deep Notch test, etc.) or other tests may be required in the case of newly
developed type of steel, outside the scope of W11, or when deemed necessary by the
Society.

3.7 Weldability tests

3.7.1 General

Weldability tests are required for plates and are to be carried out on samples of the thickest
plate. Tests are required for normal strength grade E and for higher strength steels.

3.7.2 Preparation and welding of the test assemblies

The following tests are in general required:

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a) 1 butt weld test assembly welded with a heat input approximately 15 kJ/cm
W11 b) 1 butt weld test assembly welded with a heat input approximately 50 kJ/cm.
(cont) The butt weld test assemblies are to be prepared with the weld seam transverse to the plate
rolling direction, so that impact specimens will result in the longitudinal direction.
The bevel preparation should be preferably 1/2V or K.
The welding procedure should be as far as possible in accordance with the normal welding
practice used at the yards for the type of steel in question.
The welding parameters including consumables designation and diameter, pre-heating
temperatures, interpass temperatures, heat input, number of passes, etc. are to be reported.

3.7.3 Type of tests

From the test assemblies the following test specimens are to be taken:

a) 1 cross weld tensile test

b) a set of 3 Charpy V-notch impact specimens transverse to the weld with the notch
located at the fusion line and at a distance 2, 5 and minimum 20 mm from the fusion line.
The fusion boundary is to be identified by etching the specimens with a suitable reagent.
The test temperature is to be the one prescribed for the testing of the steel grade in
question.

c) Hardness tests HV 5 across the weldment. The indentations are to be made along a 1
mm transverse line beneath the plate surface on both the face side and the root side of
the weld as follows:

 Fusion line
 HAZ: at each 0.7 mm from fusion line into unaffected base material (6 to 7 minimum
measurements for each HAZ)

The maximum hardness value should not be higher than 350 HV.

A sketch of the weld joint depicting groove dimensions, number of passes, hardness
indentations should be attached to the test report together with photomacrographs of the weld
cross section.

3.7.4 Other tests

Additional tests such as cold cracking tests (CTS, Cruciform, Implant, Tekken, Bead-on
plate), CTOD, or other tests may be required in the case of newly developed type of steel,
outside the scope of W11, or when deemed necessary by the Society.

4. Results

All the results, which are in any case to comply with the requirements of the Rules, are
evaluated for the approval; depending on the results, particular limitations or testing
conditions, as deemed appropriate, may be specified in the approval document.

All the information required under Appendix 2.2, applicable to the products submitted to the
tests, is to be collected by the manufacturer and put in the dossier which will include all the
results of the tests and operation records relevant to steel making, casting, rolling and heat
treatment of the test products.

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5. Certification
W11
(cont) 5.1 Approval

Upon satisfactory completion of the survey, approval is granted by the Society.

5.2 List of approved manufacturers

The approved manufacturers are entered in a list containing the types of steel and the main
conditions of approval.

6. Renewal of approval

The validity of the approval is to be a maximum of five years.

Renewal can be carried out by an audit and assessment on the result of satisfactory survey
during the period.*

Where for operational reasons, the renewal audit falls outside the period of approval, the
manufacturer will still be considered as approved if agreement to this audit date is made
within the original period of approval, in this instance if successful, the extension of approval
will be back dated to the original renewal date.

Manufacturers who have not produced the approved grades and products during the period
between renewals may be required to either carry out approval tests or, on the basis of
results of production of similar grades of products, at the discretion of the Society, be
reapproved.

7. Reconsideration of the approval

During the period of validity the approval may be reconsidered in the following cases:

a) in service failures, traceable to product quality

b) non conformity of the product revealed during fabrication and construction

c) discovered failure of the Manufacturer’s quality system

d) changes brought by the Manufacturer, without preliminary agreement of the Society, to

the extent of the approval defined at the time of the approval

e) evidence of major non conformities during testing of the products.

* The provision for renewal of approval is also to be applied to all grades and products which were
approved by the Society prior to an implementation of revision 4 of this UR W 11 regardless of the
validity of certificate in existing approvals. Such renewal is to be completed within five years after the
revision 4 becomes effective.

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Appendix B. Approval scheme for manufacturer of hull structural steels

W11 intended for welding with high heat input
(cont)

1. Scope

This document specifies the weldability confirmation scheme of normal and higher strength
hull structural steels stipulated in UR W11 intended for welding with high heat input over
50kJ/cm.

The weldability confirmation scheme is to be generally applied by manufacturer’s option and

valid for certifying that the steel has satisfactory weldability for high heat input welding
concerned under testing conditions.

Demonstration of conformance to the requirements of this document approves a particular

steel mill to manufacture grade of steel to the specific chemical composition range, melting
practice, and processing practice for which conformance was established. The approval
scheme does not apply to qualification of welding procedures to be undertaken by the
shipyards.

2. Application of certification

The manufacturer is to submit to the Classification Society, request of certification, proposed

weldability test program (see section 3.2) and technical documents relevant to:

a) Outline of steel plate to be certified

- grade
- thickness range
- deoxidation practice
- fine grain practice
- aim range of chemical composition
- aim maximum Ceq and Pcm
- production statistics of mechanical properties (tensile and Charpy V-notch impact
tests), if any

b) Manufacturing control points to prevent toughness deterioration in heat affected zone

when welded with high heat input, relevant to chemical elements, steel making, casting,
rolling, heat treatment etc.

c) Welding control points to improve joint properties on strength and toughness, if any.

3. Confirmation tests

3.1 Range of certification

Range of certification for steel grades is to be the following a) through e) unless otherwise
agreed by the Classification Society:

a) Approval tests on the lowest and highest toughness levels cover the intermediate
toughness level.
b) Approval tests on normal strength level cover that strength level only.

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 W11

c) For high tensile steels, approval tests on one strength level cover strength level
W11 immediately below.
(cont) d) Tests may be carried out separately subject to the same manufacturing process.
e) Certification and documentation of confirmation tests performed by other Classification
Society may be accepted at the discretion of the Classification Society.

3.2 Weldability test program

Extent of the test program is specified in section 3.5 but it may be modified according to the
contents of certification. In particular, additional test assemblies and/or test items may be
required in the case of newly developed type of steel, welding consumable and welding
method, or when deemed necessary by the Classification Society.

Where the content of tests differs from those specified in section 3.5, the program is to be
confirmed by the Classification Society before the tests are carried out.

3.3 Test plate

Test plate is to be manufactured by a process approved by the Classification Society in

accordance with the requirements of UR W11 Appendix A.

For each manufacturing process route, two test plates with different thickness are to be
selected. The thicker plate (t) and thinner plate (less than or equal to t/2) are to be proposed
by the manufacturer.

Small changes in manufacturing processing (e.g. within the TMCP process) may be
considered for acceptance without testing, at the discretion of the Classification Society.

3.4 Test assembly

One butt weld assembly welded with heat input over 50kJ/cm is to be generally prepared with
the weld axis transverse to the plate rolling direction.

Dimensions of the test assembly are to be amply sufficient to take all the required test
specimens specified in section 3.5.

The welding procedures should be as far as possible in accordance with the normal practices
applied at shipyards for the test plate concerned.

Welding process, welding position, welding consumable (manufacturer, brand, grade,

diameter and shield gas) and welding parameters including bevel preparation, heat input,
preheating temperatures, interpass temperatures, number of passes, etc. are to be reported.

3.5 Examinations and tests for the test assembly

The test assembly is to be examined and tested in accordance with the following a) through
h) unless otherwise agreed by the Classification Society.

a) Visual examination
Overall welded surface is to be uniform and free from injurious defects such as cracks,
undercuts, overlaps, etc.

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 W11

b) Macroscopic test
W11 One macroscopic photograph is to be representative of transverse section of the welded
(cont) joint and is to show absence of cracks, lack of penetration, lack of fusion and other
injurious defects.

c) Microscopic test
Along mid-thickness line across transverse section of the weld, one micrograph with
x100 magnification is to be taken at each position of the weld metal centreline, fusion line
and at a distance 2, 5, 10 and minimum 20 mm from the fusion line. The test result is
provided for information purpose only.

d) Hardness test
Along two lines across transverse weld section 1 mm beneath plate surface on both face
and root side of the weld, indentations by HV5 are to be made at weld metal centreline,
fusion line and each 0.7 mm position from fusion line to unaffected base metal (minimum
6 to 7 measurements for each heat affected zone).

The maximum hardness value should not be higher than 350 HV.

e) Transverse tensile test

Two transverse (cross weld) tensile specimens are to be taken from the test assembly.
Test specimens and testing procedures are to comply with the requirements of UR W2.

The tensile strength is to be not less than the minimum required value for the grade of
base metal.

f) Bend test
Two transverse (cross weld) test specimens are to be taken from the test assembly and
bent on a mandrel with diameter of quadruple specimen thickness. Bending angle is to
be at least 120°. Test specimens are to comply with the requirements of UR W2.

For plate thickness up to 20 mm, one face-bend and one root-bend specimens or two
side-bend specimens are to be taken. For plate thickness over 20 mm, two side-bend
specimens are to be taken.

After testing, the test specimens shall not reveal any crack nor other open defect in any
direction greater than 3 mm.

g) Impact test
Charpy V-notch impact specimens (three specimens for one set) are to be taken within 2
mm below plate surface on face side of the weld with the notch perpendicular to the plate
surface.

One set of the specimens transverse to the weld is to be taken with the notch located at
the fusion line and at a distance 2, 5 and minimum 20 mm from the fusion line. The
fusion boundary is to be identified by etching the specimens with a suitable reagent. The
test temperature is to be the one prescribed for the testing of the steel grade in question.

For steel plate with thickness greater than 50 mm or one side welding for plate thickness
greater than 20 mm, one additional set of the specimens is to be taken from the root side
of the weld with the notch located at each the same position as for the face side.

The average impact energy at the specified test temperature is to comply with the Tables
6 or 7 of UR W11 depending on the steel grade and thickness. Only one individual value
may be below the specified average value provided it is not less than 70% of that value.

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 W11

Additional tests at the different testing temperatures may be required for evaluating the
W11 transition temperature curve of absorbed energy and percentage crystallinity at the
(cont) discretion of the Classification Society.

h) Other test
Additional tests such as wide-width tensile test, HAZ tensile test, cold cracking tests
(CTS, Cruciform, Implant, Tekken, and Bead-on plate), CTOD or other tests should be
required at the discretion of the Classification Society (see section 3.2).

4. Results

The manufacturer is to submit to the Classification Society the complete test report including
all the results and required information relevant to the confirmation tests specified in section
3.

The contents of the test report are to be reviewed and evaluated by the Classification Society
in accordance with this weldability confirmation scheme.

5. Certification

The Classification Society issues the certificate where the test report is found to be
satisfactory.

The following information is generally required to be included on the certificate:

a) Manufacturer
b) Grade designation with notation of heat input (see section 6)
c) Deoxidation practice
d) Fine grain practice
e) Condition of supply
f) Plate thickness tested
g) Welding process
h) Welding consumable (manufacturer, brand, grade), if desired
i) Actual heat input applied.

6. Grade designation

Upon issuance of the certificate, the notation indicating the value of heat input applied in the
confirmation test may be added to the grade designation of the test plate, e.g. “E36-W300” (in
the case of heat input 300 kJ/cm applied). The value of this notation is to be not less than 50
and every 10 added.

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Appendix C Procedure for Approval of Corrosion resistant steels for cargo oil
W11 tanks
(cont)
Approval Procedure for Corrosion Resistant Steel

1. Scope

1.1 This document specifies, as given in W11 2.1, the scheme for the approval of corrosion
resistant steels based upon corrosion testing.

1.2 The corrosion testing is to be carried out in addition to the approval testing specified in
Appendix A1 and A2 for the approval of normal and higher strength hull structural steels.

1.3 The corrosion tests and assessment criteria are to be in accordance with the Appendix of
the Annex to Performance Standard for Alternative Means of Corrosion Protection for Cargo
Oil Tanks of Crude Oil Tankers (MSC.289 (87)).

2. Application for approval

2.1 The manufacturer is to submit to the Society a request for approval, which is to include
the following:

(a) Corrosion test plan and details of equipment and test environments.

(b) Technical data related to product assessment criteria for confirming corrosion resistance.

(c) The technical background explaining how the variation in added and controlled elements
improves corrosion resistance. The manufacturer will establish a relationship of all the
chemical elements which affect the corrosion resistance. The chemical elements added or
controlled to achieve the required level of corrosion resistance are to be specifically verified
for acceptance. Verification is to be based on the ladle analysis of the steel.

(d) The grades, the brand name and maximum thickness of corrosion resistant steel to be
approved. Designations for corrosion resistant steels are given in Table 2.1

(e) The welding processes and the brand name of the welding consumables to be used for
approval.

Table 2.1 Designations for Corrosion Resistant Steels

Type of steel Location where steel is Corrosion Resistant

effective Designation
Rolled steel for hull For lower surface of strength RCU
deck and surrounding
structures (ullage space)
For upper surface of inner RCB
bottom plating and
surrounding structures
For both strength deck and RCW
inner bottom plating

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3. Approval of test plan

W11
(cont) 3.1 The test program submitted by the manufacturer is to be reviewed by the Society, if found
satisfactory, it will be approved and returned to the manufacturer for acceptance prior to tests
being carried out. Tests that need to be witnessed by the society Surveyor will be identified.

3.2 Method for selection of test samples is to satisfy the following:

3.2.1 The numbers of test samples is to be in accordance with the requirements of the
Appendix of the Annex to Performance Standard for Alternative Means of Corrosion
Protection for Cargo Oil Tanks of Crude Oil Tankers (MSC.289 (87)).

3.2.2 The number of casts and test samples selected are to be sufficient to make it possible
to confirm the validity of interaction effects and/or the control range (upper limit, lower limit) of
the elements which are added or intentionally controlled, for improving the corrosion
resistance. Where agreed, this may be supported with data submitted by the manufacturer.

3.2.3 Additional tests may be required by the Society when reviewing the test program
against the paragraph 3.2.2

Remarks: Considerations for additional tests may include but not be limited to:

(a) When the Society determines that the control range is set by the theoretical analysis of
each element based on existing data, the number of corrosion resistance tests conducted in
accordance with the Appendix of the Annex to Performance Standard for Alternative Means
of Corrosion Protection for Cargo Oil Tanks (MSC.289 (87)) is too few to adequately confirm
the validity of the control range of chemical composition;

(b) When the Society determines that the data of the corrosion resistance test result obtained
for setting the control range of chemical composition varies too widely;

(c) When the Society determines that the validity of the corrosion resistance test result for
setting the control range of chemical composition is insufficient, or has some flaws; and

(d) When the Society's surveyor has not attended the corrosion resistance tests for setting
the control range of chemical composition, and the Society determines that additional testing
is necessary in order to confirm the validity of the test result data.

Remarks: The chemical composition of the corrosion resistant steel is to be within the range
specified for rolled steel for hull. Elements to be added for improving the corrosion resistance
and for which content is not specified are to be generally within 1% in total.

4. Carrying out the approval test

4.1 The manufacturer is to carry out the approval test in accordance with the approved test
plan.

5. Attendance of the Society's Surveyor for Test

5.1 The Society's Surveyor is to be present, as a rule, when the test samples for the approval
test are being identified and for approval tests, see also 3.1.

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6. Test Results
W11
(cont) 6.1 After completion of the approval test, the manufacturer is to produce the report of the
approval test and submit it to the Society.

6.2 The Society will give approval for corrosion resistant steel where approval tests are
considered by the society to have given satisfactory results based on the data submitted in
accordance with the provisions of this Appendix.

6.3 The certificate is to contain the manufacturer's name, the period of validity of the
certificate, the grades and thickness of the steel approved, welding methods and welding
consumables approved.

7. Assessment Criteria for Results of Corrosion Resistance Tests of Welded Joint

7.1 The results will be assessed by the Classification Society in accordance with the
acceptance criteria specified in the Appendix of the Annex to Performance Standard for
Alternative Means of Corrosion Protection for Cargo Oil Tanks (MSC.289 (87)).

End of
Document

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