Section 5 Welder qualification tests

5.1.1 The requirements of this Section relate to qualification of welders involved in welded construction and repair associated with ships, or other marine structures, and products or components intended for use on or in these structures.

5.1.2 The requirements relate to fusion welding processes that are designated as manual, semi-automatic or partly mechanised. Special consideration will be given to other welding processes adapted from these requirements.

5.1.3 The qualification test and approval range of welding operators for fully mechanised and automatic welding processes are to be carried out with reference to ISO 14732 or equivalent.

5.1.4 Prior to commencing production welding, the welder is to have performed a qualification test that satisfies these requirements. It is the responsibility of the manufacturer to ensure that the welder possesses the required level of skill for the work to be undertaken.

5.1.5 The qualification of welders is to be documented by the manufacturer and the records are to be available for review by the Surveyor.

5.1.6 Welder qualification tests made in accordance with EN, ISO, JIS, ASME or AWS may be considered for acceptance provided that, as a minimum, they are equivalent to, and meet the technical intent of these Rules in terms of qualification examination, testing, and range of approval to the satisfaction of the Surveyor. The extension of validity of welder qualifications shall be in accordance with the requirements of Ch 12, 5.7 Welders qualification certification.

5.2.1 The welding of the welder qualification test assembly is to simulate, as far as practicable, the conditions to be experienced in production and be witnessed by the Surveyor. The test is to be carried out on a test assembly piece and not by way of production welding.

5.2.2 The test is to simulate, as far as practicable, the welding techniques and practices to be encountered during production welding. The test assembly is to be designed to test the skill of the welder and have the shape and dimensions appropriate to the range of approval required.

5.2.3 The inspection length of the test weld is to be such as to permit the removal of all the necessary test specimens and for plate tests, but in no case is to be less than 250 mm. The test assembly is to be set in one of the positions as shown in Figure 12.2.4 Plate butt weld test positions to Figure 12.2.7 Pipe fillet weld test positions appropriate to the welding positions to be approved.

5.2.4 A welding procedure specification (WPS) is required for the execution of the qualification test and is to include the information specified in Ch 12, 2.2 Welding variables 2.2.1, as a minimum.

5.2.5 The test assembly is to be marked with a unique identification and the inspection length is to be identified prior commencing welding. For pipe welds, the whole circumference is to be considered as the inspection length.

5.2.6 During welding of the test assembly, the welding time is to be similar to that expected under production conditions. For manual or semi-automatic processes, at least one stop and re-start in the root and in the top surface layer is to be included in the inspection length and marked for future inspection.

5.2.7 During welding of the test assembly, minor imperfections may be removed by the welder by any method that is used in production, except on the surface layer.

5.2.8 The Surveyor may stop the test if the welding conditions are not correct or if there is any doubt about the competence of the welder to achieve the required standard.

5.3.1 Each completed test weld is to be examined and tested in accordance with the requirements of Table 12.5.1 Welder qualification test requirements. All examinations and tests are to be witnessed by the Surveyor.

5.3.2 Visual examination is to be performed in the as welded state prior to any other assessment.

5.3.3 For plate butt welds, fracture testing may be used in place of radiography.

5.3.4 Where a backing strip has been used, it is to be retained for non-destructive examinations, but is to be removed prior to performing any bend or fracture tests.

5.3.5 Where fracture tests are required, they are to sample as much of the inspection length as practicable and the test assembly may be cut into several test specimens to achieve this. Testing is to be performed as shown in Figure 12.5.1 Preparation and fracture testing of test specimens for a fillet weld in plate or Figure 12.5.2 Preparation and fracture testing of test specimens for a butt weld in plate.

Figure 12.5.1 Preparation and fracture testing of test specimens for a fillet weld in plate

Figure 12.5.2 Preparation and fracture testing of test specimens for a butt weld in plate

5.3.6 For butt weld tests in aluminium alloys both radiography and bend tests are required.

5.3.7 When bend tests are required, 2 root and 2 face bends are to be tested and where the test thickness exceeds 12 mm, these may be substituted by 4 side bends specimens. The diameter of former to be used is to be in accordance with that specified for welding procedure qualification testing given in Ch 12, 2.7 Destructive tests for steel butt welds 2.7.6.(a).

5.3.8 Where macro examination is required, the specimen is to be polished and etched to reveal the weld runs and heat affected zones, and be examined at a magnification between x5 and x10.

5.4.1 The acceptance criteria are to be in accordance with Ch 12, 2.5 Non-destructive examination (NDE) 2.5.5.

5.4.2 Fracture tests and macro-sections are to be assessed in accordance with the non-destructive examination acceptance criteria.

5.4.3 Bend tests are considered acceptable if after bending through an angle of at least 180°, there are no defects on the tension side of the specimen greater than 3 mm in any direction.

5.5.1 Where a macro-section fails to meet requirements, one additional specimen may be removed from the test assembly and examined.

5.5.2 Where a bend or fracture test specimen fails to meet requirements, two additional specimens may be prepared from the same test assembly. If there is insufficient material, the welder may be permitted to weld an additional assembly to the same WPS, at the discretion of the Surveyor.

5.5.3 Where any of the additional test specimens fails to satisfy the requirements, the test will be considered as not meeting the requirements.

5.5.4 Where a test fails to comply with the acceptance criteria, the welder may be permitted to weld a second test piece. If this does not meet requirements, the welder is to be considered as not being capable of achieving the requirements.

5.6.1 Upon successful completion of all the necessary examinations and tests, the welder is to be considered qualified. The essential variables and the range of welding conditions for which the welder is considered approved are specified in the following paragraphs.

5.6.2 Welding variables such as preheat, interpass temperature, heat input and current type are not considered welder qualification variables. However, if the WPS used for testing specify these, they are to be included in the test and the welder is expected to follow the specific instructions.

5.6.3 Where the WPS used for the welder qualification test specifies post-weld heat treatment, this need not be applied to the test weld unless bend tests are required and the material exhibits low ductility in the as welded condition.

5.6.4 The qualification test performed by a manufacturer is only applicable to workshops under the same technical control and quality system as that used for the test.

5.6.5 The welding process used in the qualification test is the process approved. However, it is possible for the welder to use more than one process in the test and the range of approval that may be applied to each will be within the limits of the essential variables appropriate to the part of the test where each welding process was used.

5.6.6 A change from welding with solid wire to metal cored wire or vice versa is allowed. A change from or to welding with flux cored wire requires a new qualification test.

5.6.7 For gas tungsten arc welding in which the wire is added manually, welding with a filler wire qualifies welding without filler wire but not vice versa.

5.6.8 Material types are to be grouped as shown in Table 12.5.2 Welder qualification materials groupings for welder qualifications. A qualification test performed on one material from a group will permit welding of all other materials within the same group. In addition, qualification on one group of materials may confer approval to weld other groups as shown in Table 12.5.3 Welder qualification, range of approval for material groups.

5.6.9 A qualification test performed on one thickness will confer approval to weld other thicknesses as specified in Table 12.5.4 Welder qualification, range of approval for material thickness. Where welding is required between materials of different thickness, the reference thickness for approval purposes is to be the lesser thickness.

5.6.10 A qualification test performed on plate confers approval to weld on pipes having an outside diameter greater than 500 mm in a fixed position (see Table 12.5.5 Welder qualification, diameter range of approval for pipes and hollow sections and Table 12.5.7 Welding position ranges for welder qualification).

5.6.11 A qualification test performed using a specific diameter of pipe will give approval to weld other diameters as shown in Table 12.5.5 Welder qualification, diameter range of approval for pipes and hollow sections. For branch welds, the diameter upon which approval is based is to be the branch member.

5.6.12 A qualification test performed on a butt weld may be considered as giving approval for fillet welds. Where a welder is employed to perform fillet welding only, a fillet welding qualification test is required. For welding T joints with full or partial penetration a butt welding qualification is required.

5.6.13 A qualification test performed on one type of weld joint will give approval to weld other types of weld joint as shown in Table 12.5.6 Range of welded joints for welder qualification.

5.6.14 A qualification test performed in one position will give approval to weld in other positions as shown in Table 12.5.7 Welding position ranges for welder qualification.

5.6.15 For manual metal arc welding with covered electrodes, a qualification test performed using an electrode with one type of coating will only be approved for welding with that type of coating. However, a qualification test performed using a basic low hydrogen type coating will confer approval to use electrodes with rutile coatings.

5.6.16 For gas shielded welding processes that use a single component shielding gas, no change to the gas composition is permitted from that tested. Where the test has used a two component shielding gas, a change in the ratio of component gases is permitted, provided that one of the components is not reduced to zero. Where the test has used a three component shielding gas, changes are permitted in the ratio of component gases and the gas with the smallest ratio may be reduced to zero, provided this does not change the shielding gas from an active one to an inert one or vice versa. In addition, where a change in shielding gas composition requires a different welding method or technique to be employed, a new qualification test will be required.

5.6.17 A change of welding flux from that used for the test is permitted.

5.6.18 A qualification for butt or fillet welding qualifies welding of tacks.

5.6.19 Where a welder is employed in the welding of tack welds only and which are not incorporated into the final weld, a test assembly in accordance with Figure 12.5.3 Dimensions and types of test assembly for butt tack welding or Figure 12.5.4 Dimensions and types of test assembly for fillet tack welding may be prepared as an alternative to full butt or fillet weld qualification.

Figure 12.5.3 Dimensions and types of test assembly for butt tack welding

Figure 12.5.4 Dimensions and types of test assembly for fillet tack welding

5.7.1 All the relevant conditions used during the test are to be entered on the welder’s qualification certificate along with the permitted range of approval.

5.7.2 If the Surveyor is satisfied that the welder has demonstrated the appropriate level of skill and all tests are satisfactory, the Surveyor will endorse the certificate verifying that the details contained on it are correct and that the test welds were prepared, welded and tested in accordance with the specified Rules, Codes or Standards.

5.7.6 For the extension of welder’s qualification validity permitted by the method detailed in Ch 12, 5.7 Welders qualification certification 5.7.4.(c), the manufacturer should have certification to a recognised quality management system under LR, or under an independent body acceptable to LR, and include the following minimum requirements:

1. A designated person is responsible for the coordination of the welder quality management system.
2. A list of all welders, including their qualification status, and welding supervisors in the shipyard/manufacturer is maintained.
3. A welder qualification certificate is issued to each qualified welder.
4. Training requirements are specified for the welder qualification programme.
5. An identification and traceability system is in place for welders and WPS used on production welds.
6. A procedure is in place to monitor performance of each welder based on the results of weld examination records and the weld repair rates. The procedure should also specify the criteria for the retesting of each welder based on the performance results.

5.7.7 Where there is any reason to question the welder’s ability, or there is a lack of continuity in the use of the welding process, or insufficient recorded evidence of acceptable weld performance, the welder is to perform a new qualification test.

5.7.8 Where the manufacturer has existing welders that have previously performed qualification tests, these may be considered for acceptance provided they satisfy the above requirements and the tests have been performed in the presence of an independent examiner that is acceptable to the Society.

5.7.9 Not withstanding the above, the Surveyor may at any time request a review of a welder’s qualification records. If there is any reason for doubt concerning the skill of the welder, the Surveyor may withdraw the qualification and require a re-qualification test to be performed.