GB/T 24598-2009 PDF in English
GB/T 24598-2009 (GB/T24598-2009, GBT 24598-2009, GBT24598-2009)
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Qualification test of welders -- Fusion welding for aluminium and aluminium alloys
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Standards related to (historical): GB/T 24598-2009
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GB/T 24598-2009: PDF in English (GBT 24598-2009) GB/T 24598-2009
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 25.160.01
J 33
Qualification test of welders - Fusion welding
for aluminum and aluminum alloys
ISSUED ON. OCTOBER 30, 2009
IMPLEMENTED ON. APRIL 01, 2010
Issued by. General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Terms and definitions ... 5
4 Symbols and abbreviated terms ... 6
5 Main parameters and range of qualification ... 8
6 Examinations and testing ... 13
7 Acceptance requirements for test pieces ... 22
8 Re-tests ... 22
9 Period of validity ... 23
10 Certificate ... 23
11 Qualified designation for welder’s qualification test ... 24
Appendix A (Informative) Welder’s qualification test certificate ... 26
Appendix B (Informative) Examples of qualified designation for welder’s
qualification test ... 28
Appendix C (Normative) Job knowledge ... 32
Appendix D (Informative) Parameters to be confirmed and traceable for
prolongation ... 35
Appendix E (Informative) Guide for classification of aluminum and aluminum
alloy ... 36
Appendix F (Informative) Description of the ISO 9017 fracture test ... 37
Qualification test of welders - Fusion welding
for aluminum and aluminum alloys
1 Scope
This standard specifies the requirements for qualification of welders for fusion
welding of aluminum and aluminum alloys.
To ensure that the exam is suitable for different product types, regions, and
testing organizations, this standard provides a set of technical rules for
systematic qualification.
This standard focuses on qualifying the skills of the welder to manually operate
the welding tongs, welding guns, welding torches, and thereby produce a weld
of acceptable quality.
This standard applies to manual welding and semi-automatic welding methods.
2 Normative references
The provisions in following documents become the provisions of this standard
through reference in this standard. For the dated references, the subsequent
amendments (excluding corrections) or revisions do not apply to this standard;
however, parties who reach an agreement based on this standard are
encouraged to study if the latest versions of these documents are applicable.
For undated references, the latest edition of the referenced document applies.
GB/T 2653 Bend test methods on welded joints (GB/T 2653-2008, ISO
5173.2000, IDT)
GB/T 3323 Radiographic examination of fusion welded joints in metallic
materials
GB/T 3375 Welding terminology
GB/T 5185 Welding and allied processes - Nomenclature of processes and
reference numbers (GB/T 5185-2005, ISO 4063.1998, IDT)
GB/T 16672 Welds - Working positions - Definitions of angles of slope and
rotation (GB/T 16672-1996, ISO 6947.1993, IDT)
GB/T 19866 Specification and qualification of welding procedures for
Material placed at the reverse side of a joint preparation for the purpose of
supporting molten weld metal.
3.5
Root run
In multi-layer welding, the runs of the first layer deposited in the root.
3.6
Filling run
In multi-layer welding, the runs deposited after the root runs and before the
capping runs.
3.7
Capping run
In multi-layer welding, the runs visible on the weld faces after completion of
welding.
3.8
Weld metal thickness
Thickness of the weld metal excluding any reinforcement.
4 Symbols and abbreviated terms
4.1 General
When filling the welder’s qualification certificate (see Appendix A), it shall use
the following symbols and abbreviations.
4.2 Reference numbers of welding processes
This standard includes the following manual and semi-automatic welding
methods (see GB/T 5185 for the reference number of welding process).
131 Metal inert gas shielded arc welding (MIG welding)
141 Tungsten inert gas shielded arc welding (TIG welding)
15 Plasma arc welding.
4.3 Abbreviations
sl - Single-layer welding;
ss - Single-sided welding.
5 Main parameters and range of qualification
5.1 General
The qualification of welder is based on the main parameters. This standard
determines the scope of approval for each main parameter. Except as
described in 5.7 and 5.8, all test pieces shall be welded using the main
parameters. If the welder is engaged in welding outside the range of
qualification, a new qualification test is required. The main parameters are.
a) Welding processes;
b) Type of test piece (plate and tube);
c) Type of weld (butt weld and fillet weld);
d) Base metal;
e) Welding consumables;
f) Size (base metal’s thickness and tube’s outer diameter);
g) Welding position;
h) Weld details (welding with backing, single-sided welding, double-sided
welding, single-layer welding, multi-layer welding).
5.2 Welding processes
Each test usually qualifies only one welding process. A change of welding
process requires a new qualification test. However, it is permitted for a welder
to be qualified for two or more welding processes by welding a single test piece
(combined welding method) or by two or more separate qualification tests. Table
1 provides the ranges of qualification for single welding process and multi-
welding process against the butt weld.
For the welding process 141, if the current is changed from DC to AC and vice
versa, it needs a new qualification test.
5.6 Welding consumables
Qualification with filler metal (e.g. welding processes 141 and 15) qualifies for
welding without filler metal, but not vice versa.
Qualification with AlMg alloy type filler metals qualifies the use of AISi alloy
types, but not vice versa.
For the welding process 131, an increase of the Helium content of the shielding
gas greater than 50% requires a new qualification test.
5.7 Dimensions
The welder qualification test of butt welds is based on the material thickness
and tube’s outer diameters. Tables 3 and 4 specify the range of qualification.
Table 5 specifies the range of qualification of the base metal’s thickness for fillet
welds.
For branch tube’s welding, based on the following conditions, the range of
qualification of the base metal’s thickness is determined in accordance with
Table 3, the range of qualification of the tube’s outer diameter is determined in
accordance with Table 4.
- Set-in type. the thickness and outer diameter of the base metal of the
branch tube;
- Set-in or set-through type. the thickness of the base metal of the main tube
or housing and the outer diameter of the branch tube.
For test pieces with different outer diameters and base metal thicknesses,
welders are qualified as follows.
1) The range of qualification of base metal’s thickness is as specified in
Table 3;
2) The range of qualification of tube’s outer diameter is as specified in
Table 4.
Table 3 -- Range of qualification of base metal’s thickness for test piece
of butt weld (multiple welding methods), Unit in mm
Thickness of test piece, t Range of qualification
t ≤ 6 0.5t ~ 2t
t > 6 ≥ 6
l2 - Length of test plate;
t - Thickness of test piece (plate thickness or wall thickness);
z - Dimension of weld leg;
0.5t ≤ α ≤ 0.7t.
Figure 4 -- Test piece’s dimensions for fillet weld of tube/plate
6.3 Welding conditions
Welder’s qualification test shall be carried out in accordance with pWPS or WPS
as defined in GB/T 19867.1.
Welding during the qualification test shall meet the following requirements.
a) The welding time of the test piece shall be consistent with the welding time
under normal production conditions;
b) The test piece shall have at least one stop and one re-start in the root run
and in the capping run and be identified in length to be examined;
c) Any post-welded heat treatment required in the pWPS or WPS can be
omitted unless bend or tensile tests are required;
d) Identification of the test piece;
e) The welder may, only with the permission of the examiner or examining
body, remove minor imperfections by grinding or planing, except on the
surfaces.
6.4 Testing method
Each completed weld shall be tested in the as-welded condition as specified in
Table 9.
The additional tests specified in Table 9 shall be carried out after passing the
visual inspection.
When using permanent backing in the qualification test, it shall be removed
prior to destructive testing.
In order to clearly show the weld, it shall be prepared and etched on one side
of the macro specimen, polishing is generally not required.
When radiographic testing of butt welds made by welding process 131 (MIG
welding) is undertaken, it shall be supplemented by either two additional bend
tests (one face and one root or two side bends) or two fracture tests (one face
7 Acceptance requirements for test pieces
The test piece shall be evaluated in accordance with the acceptance
requirements specified in the corresponding imperfection type.
Prior to any testing, it shall make the following inspections.
- All splashes are removed;
- No grinding has been performed on the root and the face side of the weld
(as per 6.3);
- The stop and restart in the root run and in the capping run are identified (as
per 6.3);
- The profile and dimensions are acceptable.
Unless otherwise specified, the acceptance requirements for imperfections
found by the test method in accordance with this standard shall be evaluated in
accordance with the provisions of GB/T 22087. If the imperfections are within
the quality level B as specified in GB/T 22087, a welder is qualified, except for
the following imperfections, such as the excess weld metal (butt weld),
excessive convexity (fillet weld), excessive throat thickness and excessive
penetration, for which level C shall apply.
Bend test specimens shall not reveal any one single flaw greater than 3 mm in
any direction. Flaws appearing at the edges of a test specimen during testing
shall be ignored in the evaluation, unless there is evidence that cracking is due
to incomplete penetration, inclusion slag or other flaw.
If the imperfection in the welder’s test piece exceeds the permitted maximum
specified, then the welder fails the test.
The corresponding acceptance criteria for non-destructive testing shall make
reference to the relevant standards, all destructive and non-destructive testing
shall be carried out in accordance with the prescribed procedures.
8 Re-tests
If any test fails to comply with the requirements of this document, the welder
shall be given the opportunity to repeat the qualification test.
If it is established that failure is due to metallurgical or other extraneous causes
that cannot be directly attributed to the welder’s lack of skill, it shall allow an
additional qualification test.
The welder’s qualification certificate shall be issued solely by the examining
body and shall include the contents listed in Appendix A. It is recommended to
use the format of Appendix A as a qualification certificate for a welder qualified.
If any other format of welder’s qualification certificate is used, the certificate
must contain the content required by Appendix A.
In principle, a welder’s qualification certificate shall be issued for each test piece.
If a welder has welded multiple test pieces, it can also be summarized on a
welder’s qualification certificate in accordance with its scope of application.
Except for the examples described in 5.7, only one of the following main
parameters is allowed to be changed.
- The type of weld;
- The welding position;
- The thickness of base metal.
The welder’s qualification certificate shall avoid ambiguity.
It shall use “qualified” or “not assessed” to indicate the actual skills assessment
and professional knowledge test (see Appendix A).
Any changes to the test’s main parameters beyond the scope of qualification
require new test and qualification.
11 Qualified designation for welder’s qualification test
The designation of a welder qualification shall comprise the following items.
a) The number of this standard;
b) Main parameters
1) Welding process. refer to 4.2, 5.2 and GB/T 16672;
2) Type of specimen. plate (P), tube (T), refer to 4.3.1 and 5.3;
3) Type of weld. butt weld (BW), fillet weld (FW), refer to 5.4;
4) Group of material. see 5.5;
5) Welding consumables. see 5.6;
6) Dimension of specimen. material thickness t and outer diameter of the
tube, see 5.7;
Appendix C
(Normative)
Job knowledge
C.1 General
It is recommended to conduct a job knowledge test for the welder, but it is not
mandatory.
If job knowledge test is carried out, it shall be recorded on the welder’s
qualification certificate.
This Appendix outlines the job knowledge that welders shall master to ensure
they follow the procedures and comply with the common practices. This
Appendix only specifies the overall objectives or categories of job knowledge,
which are only the most basic requirements.
Job knowledge test can be conducted in one of the following ways (or a
combination of these).
a) Written test (multiple choices);
b) Oral test based on a set of written questions;
c) Computer test;
d) Demonstration/observation testing in accordance with a written set of
criteria.
The test of job knowledge is limited to the matters related to the welding process
used in the test.
C.2 Requirements
C.2.1 Welding equipment
a) Identification and assembly of essential components and equipment;
b) Type of welding current;
c) Correct connection of welding circuit.
C.2.2 Welding process
a) Type and size of electrode;
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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