GB/T 24598-2009Qualification test of welders -- Fusion welding for aluminium and aluminium alloys (English PDF)

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).

4.3 Abbreviations

sl - Single-layer welding;

ss - Single-sided welding.

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 <= alpha <= 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

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;

......