CERTIFICATION SCHEME FOR WELDING AND INSPECTION PERSONNEL
DOCUMENT No. CSWIP-ISO-NDT-11/93-R
Requirements for the Certification of Personnel
Engaged in Non-Destructive Testing
APPENDIX 1
Examination Format and Syllabuses for the Certification of
Personnel Engaged in Non-Destructive Testing of Welded Joints
and General Engineering Components
PART 7: Examination format and syllabus on which candidates
for ACFM Inspector, Level 1, 2 and 3 will be examined
1st Edition September 2001
Issued under the authority of the Governing Board for Certification
All correspondence should be addressed to:
TWI Certification Ltd
Granta Park, Great Abington, Cambridge CB1 6AL, UK
Telephone: +44 (0) 1223 891162;
Telefax: +44 (0) 1223 894219.
E:mail: twicertification@twi.co.uk
Web: http://www.twi.co.uk
CSWIP is administered by TWI Certification Ltd
The use of the UKAS Accreditation Mark indicates accreditation in respect of those activities covered by
Accreditation Certificate No 25
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EXAMINATION FORMAT AND SYLLABUSES ON WHICH CANDIDATES FOR
CERTIFICATION IN THE NON-DESTRUCTIVE TESTING OF WELDS AND
GENERAL ENGINEERING COMPONENTS WILL BE EXAMINED
1 ACFM INSPECTOR – EXAMINATION FORMAT
1.1 Level 1 – Two categories of certification are available:
• general engineering (covering welds, plates, castings, forging and bars made
of ferritic steel or electromagnetically similar materials, excluding rails)
• rails
Endorsements are available for the inspection of:
• aluminium
• stainless steels
• rails
1.1.1 General Theory Examination
h 40 multiple choice questions
h Time allowed: 60 minutes.
h Weighting factor: 0.25
h Pass mark: 70%
1.1.2 Specific Theory Examination
h 20 multiple choice questions
h Time allowed: 30 minutes
h Weighting factor: 0.25
h Pass mark: 70%
1.1.3 General Practical
In the practical part, the candidate is required to set up and conduct
operational and function checks on equipment and probes; record
function check data and print out hard copy.
h Time allowed: 30 minutes
h Weighting factor: 0.2
h Pass mark: 70%
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1.1.4 Specific practical
In the specific practical part the candidate is required to carry out
inspections following written procedures as specified by an NDT level 2
operator. The candidate is required to test and report on two specimens
selected by the examiner; carry out sizing for length and depth; record
inspection data in accordance with accepted conventions; transfer
inspection data files to long term storage.
h Time allowed: 1 hour
h Weighting factor: 0.3
h Pass mark: 70%
h
1.1.5 Additional Endorsements – Level 1
For those seeking endorsements in: ACFM inspection of aluminium;
stainless steel and the inspection of rails, endorsement examinations may
be taken at the same time as the initial examination, or as a separate
examination at a later occasion, providing the candidate holds a valid
Level 1 certificate.
1.2 Level 2 - Two categories of certification are available:
• general engineering (covering welds, plates, castings, forgings and bars made
of ferritic steel or electromagnetically similar materials, excluding rails)
• rails
Endorsements are available for the inspection of:
• aluminium
• stainless steels
• rails
1.2.1 General Theory Examination
h 40 multiple-choice questions.
h Time allowed: 60 minutes
h Weighting factor: 0.25
h Passmark: 70%.
1.2.2 Specific Theory Examination
h 20 multiple-choice questions
h Time allowed: 30 minutes duration.
h Weighting factor: 0.25
h Passmark is 70 %.
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1.2.3 General Practical Examination
In the practical part, the candidate is required to choose the necessary
probes and equipment to conduct the test; conduct operational and
function checks on equipment and probes; record function check. Data
and print out hard copy.
h Time allowed: 30 minutes
h Weighting factor: 0.1
h Passmark: 70%.
1.2.4 Specific Practical Examination
To test and report on three specimens selected by the examiner; carry out
sizing for length and depth on a fatigue crack specified by the examiner;
record inspection data in accordance with accepted conventions; transfer
inspection data files to long term storage.
h Time allowed: 1 hour 30 minutes
h Weighting factor: 0.3
h Passmark: 70%.
1.2.5 Instruction writing – practical
To write an NDT instruction suitable for Level 1 personnel.
• Time allowed: 1 hour
• Weighting factor 0.1
• Passmark 70%
1.2.6 Additional Endorsements – Level 2
For those seeking endorsements in: ACFM inspection of aluminium;
stainless steel and the inspection of rails, endorsement examinations may
be taken at the same time as the initial examination, or as a separate
examination at a later occasion, providing the candidate holds a valid
Level 2 certificate.
1.3 Level 3 – Welds, plates, castings, forgings, bars and rails made of ferritic steel (or
electromagnetically similar material), aluminium or stainless steel.
1.3.1 Section A (Exempt if already holding Level 3)
No of questions Time allowed Weighting Passmark
a) Materials science
30 45 minutes 0.25 70%
and processing
b) Other NDT
60 1 hr 30 minutes 0.5 70%
methods
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c) NDT personnel
30 45 minutes 0.25 70%
certification
Section B - Level 3 knowledge of the test method
50 multiple choice questions
Time allowed: 1 hr 15 minutes
Weighting factor: 0.333
Passmark: 70%
1.3.2 Specific theory – application of the NDT method
40 multiple choice questions
Time allowed: 1 hour
Weighting factor: 0.333
Passmark: 70%
NDT Procedure preparation for a component selected by the examiner
Time allowed 3 hours
Weighting factor 0.333
Passmark 70%
2 ACFM INSPECTOR – SYLLABUSES
2.1 Level 1 ACFM Syllabus
2.1.1 General Theory
a) Overview of NDT techniques.
Visual inspection; MPI; History of electromagnetic testing
b) Electricity
Formation of electrical current; current and voltage; resistance
and Ohm’s law; alternating current
c) Magnetism
Line of force and force fields; residual magnetism; effect of
material geometry on magnetic fields
d) Electromagnetism
Induction and magnetic fields; magnetic permeability; induced
magnetic flux; magnetic field produced by a current
e) Eddy Currents
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Eddy current induced by a magnetic field; fields created by
eddy currents; eddy current distribution; standard depth of
penetration; factors affecting penetration; theory of deflection
of currents by defects
2.1.2 Specific ACFM Theory
a) ACFM Theory
Uniform fields; interaction of field with defects; effects of field
curvature; Bx and Bz field components; typical displays; Bx and
Bz timebase; butterfly plot; ACFM defect models
b) ACFM Equipment
Equipment design and construction; equipment set up and basic
operation; basic maintenance; potential equipment faults, causes
and corrective actions
c) ACFM Manual and Array Probes
Simple probes; field generation; Bx and Bz sensors; multiple coil
configurations; advantages and limitations of array probes;
position encoders; X and Y field direction switching; optical
encoder; identity chip; multiple Bz coil pencil probes
d) ACFM Software
Role of individual package components; task based operation;
importance of component identification; software set up;
operation of main inspection screen
e) Defect Sizing
Manual software sizing; automatic sizing and limitations, defect
sizing limits defect detection limits; minimum detectable defect
size and measurement
f) Basic Signal Interpretation
Signals influenced by geometry and material variations; defect
shape and orientation; edge effects; influence of attachments;
material changes; surface finish; effects of non-conductive
coatings; false indications and causes
g) Basic scanning techniques
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Function checks; probe deployment including A / C / T direction;
software operation to start and stop scan; operation of markers
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h) Detailed Signal interpretation
Relationship between Bx, Bz and butterfly plot; typical signals
from spark eroded slot; general strategies for crack identification;
effect on signal from, lift off, plate edges, welds, bolt holes, other
general geometry effects, inclined defects, transverse defects
i) Defect sizing
Use of ACFM model; data required to size using models; sizing
problems
j) Data
Storage of data; retrieval of data
k) Reporting
Marking the product under test; individual data print outs;
creating standard reports; retrieval of information
l) Standards
The standards and specifications to be used will be relevant to the
region in which the examination is to be conducted and to the
employment of the candidate.
2.1.3 Specific Theory – General Engineering
a) Welding technology
Terminology for welds, welded joints, welding procedures; types
of defects in welds and parent metals detectable by ACFM
inspection methods.
b) Basic Casting Production Methods – Finished Products
Definition of casting how it works; types of defect in castings
detectable by ACFM inspection methods
c) Wrought Production Processes
Definition of rolling and how it works; types of defects in rolled
material detectable by ACFM inspection methods; definition of
forging and how it works; types of defect in forged products
detectable by ACFM inspection methods.
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d) Rails
Stress areas; types of defect and their related signals; sizing
different defect types
e) Wheelsets
Axles; wheels
2.2 Level 2 ACFM Syllabus
2.2.1 General Theory
As for level 1 but the examination questions will be more complex.
2.2.2 Specific Theory
As for Level 1, plus:
a) ACFM Specific Theory
Probe characteristics and selection
b) Defect Sizing
Limitations of ACFM model; advanced manual sizing
c) Safety Precautions
Fire hazards; electrical safety
d) Conduct of test
Test procedures and reasons for NDT instructions; briefing of the
remote probe operator; minimum qualifications for remote probe
operator; supervision of level 1 personnel; production of probe
files; computer file handling
e) Detailed Signal Interpretation
Types of discontinuity and their identification; relevant and non-
relevant indications and their cause; identification of crack
features; capabilities and limitations of other NDT methods in
terms of detection; characterisation and confirmation of defects
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f) Reporting
Responsibilities for reporting; origination and authentication of
NDT reports; content and layout of report; presentation of the
inspection results of an NDT report; hard copy computer
generated reports; maintenance and retention of records
2.2.3 Specific Theory – General Engineering
As for Level 1 plus:
a) Welding and Wrought Product Technology
Terminology of welds; basic principles of fusion welding
processes; methods of producing welds including, MMA, TIG,
MAG, Submerged Arc, and Electroslag; rail weld types
Basic types of welds including, fillet welds, butt welds. Variable
configuration welds including, ‘T’s nozzles and nodes
Terminology for wrought products including, forging, hammer
forging and press forging. Methods of casting
Influence on techniques of geometry, size, surface condition,
parent metal composition; influence of non – conductive and
conductive paint coatings and weld repairs; types of defect in
welds and parent metals including lack of fusion, porosity, worm
holes and cracks
b) Equipment maintenance
Probe care; trouble shooting; instrument and battery care
c) Reporting
Configuring customers reports; emailing reports; incorporating
results into reports; searching for and emailing data records
2.3 Level 3 ACFM Syllabus
2.3.1 General theory
2.3.1.1 Section A
1 Materials, Processes and Product Technology:
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Material Technology
Properties of materials, origin of discontinuities and
failure modes, statistical process control and
probability of detection.
Basic Production – Crude and Finished Products
Ingot types narrow end up and wide end up, concast
methods (continuous casting process). Definition
used in the production of ingots and casting.
Difference between ingot and concast production
processes.
Ingot casting further hot working, rolling, forging
and extrusion.
Basic Casting Production Methods – Finished
Products
Methods of casting: sand casting, die casting,
investment casting
Basic defects associated with cast products, their
appearance and how they are formed: shrinkage,
inks, cold shuts, porosity, laps, hot tears, cracks
Wrought Production Processes
Rolling process: primary rolling – blooms and slabs,
secondary rolling, billets, sections and plates, cold
rolling, sheets and strips, basic rolling defects,
appearance and how they are formed
Forging: open die forging and press forging, closed
die forging
Basic forging defects, their appearance and how
they are formed: forging bursts, laps, seams, cracks
Extrusion: definition of and how it works, why
extrusion is used instead of rolling or forging
Heat Treatment Processes
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Annealing. How annealing is carried out and the
results obtained, full anneal and definitions, sub
critical anneal and definition
Normalising: how it is carried out and the results
obtained.
Stress relieving. What stress relieving is and why it
is carried out.
Machining and material removal
Turning, boring, milling, grinding and
electrochemical.
Surface finishing and corrosion protection.
Shot peening, grit blasting, painting, plating, chemical
conversion coatings.
Non-metals and composite materials processing
Dimensional Metrology
2 Other NDT Methods:
Electromagnetic Testing
Principles, properties of eddy currents, effect of
varying frequency, equipment, application and test
results interpretation.
Magnetic Particle Inspection
Principles, technique selection, equipment,
application and test results interpretation.
Liquid Penetrant Inspection
Principles, technique selection, equipment,
application and test results interpretation.
Radiographic Inspection
Principles, technique selection, equipment,
application and test results interpretation.
Ultrasonic Inspection
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Principles, technique selection, equipment,
application and test results interpretation.
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Visual and Optical Inspection
Principles, technique selection, equipment,
application and test results interpretation.
3 Standards and Documentation Relating to the
Certification of NDT Operators
ISO 9712, EN 473, SNT-TC-1A
2.3.1.2 Section B
Candidates for Level 3 examinations will be questioned
on the contents of the syllabus for Levels 1 and 2, the
questions will however be of a more complex nature.
2.3.2 Specific Theory
Candidates for Level 3 examinations will be questioned on the
contents of the syllabus for Levels 1 and 2, the questions will
however be of a more complex nature.
REFERENCE LITERATURE
Product Technology Classroom Training Handbook – The British Institute of NDT 1995
‘Ultrasonic Testing of Materials’ by J and H Krautkramer. George Allen & Unwin Limited,
London, 1990 ISBN 0387512314.
‘Principles and practice of non-destructive testing’ edited by Dr J H Lamble. Heywood and
Company, London, 1962.
Non-Destructive Testing (second edition, 1991) by R Halmshaw. Edward Arnold, London
1991 ISBN 0340545216.
TWI Training Hand Book for electromagnetic inspection using ACFM (July 2000)
ASNT Level III Study Guide.
NDT Handbook, volume 7 Ultrasonic Handbook, ASNT 1991, Columbus, Ohio ISBN
0931403049.
TSC Handbook and operating instructions manuals. Technical Software Consultants Ltd, 6
Mill Square, Featherstone Road, Wolverton Mill, Milton Keynes, MK12 5RB
Copyright© 2001, TWI Certification Ltd
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