Section 2 Welding procedure qualification tests for steels

2.1.1 The requirements of this Section relate to welding procedure test requirements of carbon, carbon-manganese steels and low alloys steels. Additional requirements for austenitic and austenitic/ferritic duplex stainless steels, aluminium and copper alloys are specified in Sections 3 and 4 respectively.

2.1.2 Prior to performing the welding procedure qualification test, the manufacturer is to present to the Surveyor a preliminary Welding Procedure Specification (pWPS) detailing the welding processes, positions, joint types, materials and heat treatments to be performed during the test. The pWPS is to be presented for information prior to commencing the test.

2.1.3 The type and extent of testing to be applied to each welding procedure test is to be in accordance with subsequent Sections of this Chapter.

2.1.4 For the welding procedure approval, the welding procedure qualification tests given in this Section are to be carried out with satisfactory results. Welding procedure specifications are to refer to the test results achieved during welding procedure qualification testing.

2.2.1 In order that the conditions of the qualification test may be applied to production welding operations, the appropriate variables are to be recorded by the manufacturer during welding and testing from the following list:

1. The unique qualification reference number and the date of welding;

2. The material type, grade, product form, dimensions and identification;

3. Welding process(es), including tack welds;

4. Joint type, dimensions and surface condition;

5. Welding position(s);

6. Welding technique(s), weaving, multiple electrodes, etc;

7. Welding consumables including fluxes, shielding gases, etc;

8. Control of consumables, baking or drying conditions, etc;

9. Welding parameters, current, voltages, travel speeds, etc;

10. Number and sequence of weld runs;

11. Backing materials including any backing gas;

12. Preheats and interpass temperatures;

13. Methods used for cleaning and inspection of root deposits;

14. Post-weld heat treatment, temperature and cycle times;

15. Special weld profiling requirements.

2.2.2 Other variables may need to be recorded depending on the particular welding process or application and are to be agreed with the Surveyor, for example the peak and base current and cycle times for pulse welding, electrode type and nozzle size for GTAW welding, etc.

2.3.1 Tests are to be performed using the welding process and positions anticipated for actual construction. The weld test assemblies are to be representative of construction conditions and are to be welded in the same manner as intended for the actual production welds. Where prefabrication primers are used in the shipyard, these are to be included in the test assemblies.

2.3.2 For plate tests, the direction of plate rolling relative to the weld direction is to be considered. Where the material used for the test requires longitudinal impact tests, the plate rolling direction is to be perpendicular to the weld direction and for material which requires impact testing in the transverse direction, the rolling direction is to be parallel to the weld direction. For weld tests intended for liquefied gas storage or cargo tanks and associated process pressure vessels, the direction of plate rolling is to be parallel to the weld direction in all cases.

2.3.3 Typical test assemblies are shown in Figure 12.2.1 Butt weld test assembly in plate to Figure 12.2.3 Fillet weld test assembly in plate. These are a minimum requirement to permit the removal of all the necessary mechanical test specimens. Where impact tests or other toughness tests are required, the total width is not to be less than 8 times the material thickness of the thicker material being joined.

Figure 12.2.1 Butt weld test assembly in plate

Figure 12.2.2 Butt weld test assembly in pipe

Figure 12.2.3 Fillet weld test assembly in plate

2.3.4 Welding procedure test assemblies are to be welded separately from production welds and are to be marked with the unique test identification number. The individual pieces of the test assembly may be held together to maintain their relative joint conditions by means of suitable tack welds, clamps or strongbacks.

2.3.5 Welding of the test assemblies and testing of test specimens is to be monitored by the Surveyor.

2.3.6 The test assembly is to be placed in one of the welding positions shown in Figure 12.2.4 Plate butt weld test positions to Figure 12.2.7 Pipe fillet weld test positions, as specified in the test Welding Procedure Specification (pWPS) and the specified level of preheat applied prior to the start of welding.

Figure 12.2.4 Plate butt weld test positions

Figure 12.2.5 Pipe butt weld test positions

Figure 12.2.6 Plate fillet weld test positions

Figure 12.2.7 Pipe fillet weld test positions

2.3.7 Designations for equivalent welding positions shown by different standards are shown in Table 12.2.1 Equivalent designations of welding positions.

2.4.1 Welding of the test assembly is to be carried out in accordance with the agreed pWPS. Where, during the progress of the test, it is found necessary to change the conditions specified on the pWPS, this is to be brought to the attention of the Surveyor. If agreed, the test may be permitted to continue with the new conditions and these are to be recorded.

2.4.2 Where the production work requires welding over tack welds, the test is to simulate this condition and the tack welds are to be included in the inspection length of the test weld and their position recorded.

2.4.3 For manual and semi-automatic welding processes, weld stops and re-starts are to be included in the inspection length of the test weld.

2.4.4 Fillet weld test assemblies are welded on one side only.

2.4.5 Where the construction welding is predominately fillet welding, in addition to the butt weld qualification test, a fillet weld qualification test is to be performed to confirm that acceptable weld quality is achieved.

2.5.1 On completion of welding, prior to sectioning for mechanical tests, the inspection length of the test assembly is to be subjected to both visual examination and surface crack detection.

2.5.2 Butt weld assemblies are also to be subjected to radiographic or ultrasonic examination over the whole inspection length of the weld.

2.5.3 For welds in steels with specified yield strength less than 420 N/mm², and with carbon equivalent less than or equal to 0,41 per cent, NDE may be performed as soon as the test assembly has cooled to ambient temperature. For other steels, NDE is to be delayed for a period of at least 48 hours after the test assembly has cooled to ambient temperature.

2.5.4 Where post-weld heat treatment is required, NDE is to be performed after the heat treatment is complete.

2.5.5 All NDEs are to be carried out in accordance with the requirements of Ch 1, 5 Non-destructive examination. Assessment of results is to be in accordance with ISO 5817 Level B except for excess convexity and excess throat thickness where Level C will apply. Linear porosity is not permitted.

2.5.6 As an alternative to radiography, ultrasonic examination may be carried out and acceptance criteria that are considered to result in equivalent weld quality (in accordance with Ch 12, 2.5 Non-destructive examination (NDE) 2.5.5) are to be agreed, with the Surveyor, prior to the tests being carried out. Ultrasonic testing will be subject to the thickness limitation specified in Ch 13, 2.12 Non-destructive examination of steel welds 2.12.5.

2.5.7 Where the test assembly does not satisfy the nondestructive examination acceptance criteria, the test is to be rejected. A duplicate test assembly may be welded using the original welding conditions. If this fails NDE, the welding procedure is to be considered as incapable of achieving the requirements without modification.

2.5.8 Subject to prior agreement with the Surveyor, where unacceptable imperfections are of a volumetric nature and are localised in one small area of the test assembly, the test may be permitted to continue and specimens for destructive testing may be removed, avoiding this area.

2.6.1 The weld test assembly may only be sectioned for destructive testing after any heat treatment and the required non-destructive examinations have been completed successfully.

2.6.2 The dimensions of the test specimens and testing conditions are to be in accordance with the requirements specified in Ch 2 Testing Procedures for Metallic Materials.

2.6.3 The results of destructive tests are to be assessed in accordance with the acceptance criteria specified in Ch 12, 2.12 Mechanical test acceptance criteria for steels, unless other, more stringent requirements are specified for the application.

2.6.4 Where a weld test is made between materials of different grades, the acceptance criteria that are to be applied are those applicable to the lower grade material.

2.7.1 The test assembly is to be sectioned for mechanical testing in accordance with Figure 12.2.8 Butt welds in plate or Figure 12.2.9 Butt welds in pipe less than 750 mm diameter.

Note 1 Radiographic examination may be replaced by ultrasonic examination for test assembly thickness of 8 mm or above.

Note 2 If required by Figure 12.2.11 Locations of V-notch for butt weld of normal heat input (heat input ≤ 50 kJ/cm) and Figure 12.2.12 Locations of V-notch for butt weld of high heat input (heat input > 50 kJ/cm).

Figure 12.2.8 Butt welds in plate

Note 1 Radiographic examination may be replaced by ultrasonic examination for test assembly thickness of 8 mm or above.

Note 2 If required by Figure 12.2.11 Locations of V-notch for butt weld of normal heat input (heat input ≤ 50 kJ/cm) and Figure 12.2.12 Locations of V-notch for butt weld of high heat input (heat input > 50 kJ/cm).

Figure 12.2.9 Butt welds in pipe less than 750 mm diameter

2.7.2 The longitudinal all weld metal tensile test specimen is to be of circular cross-section as detailed in Ch 11, 2.1 Dimensions of test specimens 2.1.1. Where more than one welding process or type of consumable has been used to make the weld, test specimens are to be removed from each respective area of the weld. This does not apply to the process or consumables used to make the root or first weld run. During the test, the yield or proof stress, ultimate tensile strength, and elongation to failure are to be recorded.

2.7.3 Where approved welding consumables have been used, the longitudinal all weld metal tensile test may be omitted. For Type C independent tanks intended for liquefied gases, the all weld tensile test is mandatory for all welding procedure tests.

2.7.4 The transverse tensile test specimen is to be of full thickness with the dimensions shown in Ch 11, 2.1 Dimensions of test specimens 2.1.1. The tensile strength and fracture locations are to be reported.

2.7.5 Where the maximum load required to fracture the transverse tensile specimen is likely to exceed the capacity of the tensile testing equipment, several tensile specimens may be removed through the thickness and tested. Specimens are to be prepared such that they overlap in the thickness direction so that the full plate thickness is tested.

2.7.6 Transverse bend specimens of rectangular section are to be prepared with the weld centred in the middle of the specimen as shown in Figure 12.2.10 Transverse bend test specimens. For material of thickness 12 mm or greater, the face and root bends may be substituted by side bend tests. Where there is a significant difference between the strength of the weld and base material, longitudinal bend specimens may be used. The weld reinforcement may be removed by grinding or machining prior to testing and the edges rounded to a radius not exceeding 10 per cent of the specimen thickness. Each specimen is to be bent through an angle of at least 180°. The bend test ratio is to be the lesser of the following:

1. D f

   =

   (D/t) + 1

   or

2. D f

   =

   100/E m (rounded up to the next whole number)

   where

   D f	=	is the bend test ratio
   (D/t)	=	is the value from Table 11.3.3 Requirements for butt weld tests (covered electrodes), Table 11.4.3 Requirements for butt weld tests (wire-flux combinations) or Table 11.8.2 Requirements for butt weld tests (all techniques) in Chapter 11, as appropriate
   E m	=	is the minimum specified percentage elongation for the test material (based on a proportional gauge length of

2.7.7 Where the weld test is made between different material types, the requirements of Ch 12, 2.7 Destructive tests for steel butt welds 2.7.8 are to be applied to the material with the lower toughness specification.

Figure 12.2.10 Transverse bend test specimens

2.7.8 For hull structural steels, impact test specimens are to be prepared from the locations shown in Figure 12.2.11 Locations of V-notch for butt weld of normal heat input (heat input ≤ 50 kJ/cm) or Figure 12.2.12 Locations of V-notch for butt weld of high heat input (heat input > 50 kJ/cm), with the notch perpendicular to the plate surface and have the dimensions and proportions in accordance with Ch 2, 3 Impact tests. Where more than one welding process or type of consumable has been used to make the weld, test specimens are also to be removed from these respective parts of the weld. Note that this does not apply to the welding process or consumables used solely to make the root or first weld run. Where the weld thickness exceeds 50 mm, an additional set of impact tests is required from the root area of the weld irrespective or whether different welding process or welding consumables are used as shown in Figure 12.2.11 Locations of V-notch for butt weld of normal heat input (heat input ≤ 50 kJ/cm) and Figure 12.2.12 Locations of V-notch for butt weld of high heat input (heat input > 50 kJ/cm).

Figure 12.2.11 Locations of V-notch for butt weld of normal heat input (heat input ≤ 50 kJ/cm)

Figure 12.2.12 Locations of V-notch for butt weld of high heat input (heat input > 50 kJ/cm)

2.7.9 For offshore structures and pressure vessels, impact test specimens are not required to be notched at the FL + 10 mm location. Where more than one welding process or type of consumable has been used to make the weld, test specimens are to be removed from the respective areas of the weld. This does not apply to the process or consumables used solely to make the root or first weld run.

2.7.10 For pressure vessels and tanks employed in transportation of liquefied gases, Charpy impact test locations from the weld and heat affected zone are to be in accordance with Figure 12.2.13 Locations of V-notch tests for butt welds intended for liquefied gas containment systems.

Figure 12.2.13 Locations of V-notch tests for butt welds intended for liquefied gas containment systems

2.7.11 At least one macro examination specimen is to be removed from the test plate, near the end where welding started. The specimen is to include the complete cross-section of the weld and the heat affected zone and be prepared and etched to clearly reveal the weld runs and the heat affected zone. Examination is to be performed under a magnification of between x5 and x10.

2.7.12 A chemical analysis of the weld metal is to be performed on the macro specimen where approved welding consumables have not been used. The results are to comply with the limits given in the welding consumable specification.

2.7.13 Hardness surveys:

1. A Vickers hardness survey is to be performed on the macro specimen taken from the weld start end of the test assembly in accordance with that shown in Figure 12.2.14 Hardness testing locations for butt welds, using a test load not in excess of 10 kg. For each row of indents, there are to be a minimum of 3 individual indentations in the weld metal, the heat affected zones (both sides), the base metal (both sides), and in addition, 2 indentations are required in the grain coarsened heat affected zone, one above and one below the hardness survey row. The recommended distance between indents is 1,0 mm, but the distance between indents should not be less than the minimum specified in ISO 6507-1.
2. For steel grades EH47, EH47-BCA1 and EH47-BCA2 an additional row of indents is required from the mid-thickness of macro specimen.

Figure 12.2.14 Hardness testing locations for butt welds

2.8.1 Fillet weld test assemblies are to be sectioned for destructive testing in accordance with Figure 12.2.3 Fillet weld test assembly in plate and as follows:

1. two fracture tests;

2. three macro-sections;

3. one hardness survey.

2.8.2 Two fracture test specimens are to be removed from the test weld and are to be subjected to testing by bending the upright plate onto the through plate to produce fracture, as shown in Figure 12.2.3 Fillet weld test assembly in plate.

2.8.3 At least three macro examination specimens are to be removed from the test plate. The specimens are to include the complete cross-section of the weld and the heat affected zone and is to be prepared to clearly reveal the weld runs and the heat affected zone. One of the specimens is to include a weld stop/start position. Examination is to be performed under a magnification of between x5 and x10.

2.8.4 A Vickers hardness survey is to be performed on the macro specimen taken from the weld start end of the test assembly in accordance with that shown in Figure 12.2.15 Hardness test locations for fillet welds, using a test load not exceeding 10 kg.

Figure 12.2.15 Hardness test locations for fillet welds

2.9.1 Full penetration ‘T', ‘K’ and ‘Y’ joints for structural applications and nozzle welds for pressure vessels are to be sectioned for testing in accordance with Figure 12.2.16 Location of macro-examination test specimens for T, K and Y joints and tested as detailed below:

1. three macro specimens;

2. impact tests from the weld, fusion line and fusion line + 2 (where the material thickness permits);

3. one hardness survey.

In addition, butt weld tests are to be performed in accordance with Ch 12, 2.7 Destructive tests for steel butt welds, using the same welding conditions, in order to verify acceptable weld and heat affected zone properties.

2.9.2 The impact tests are to be removed from the vertical (up) position ‘B’ in Figure 12.2.16 Location of macro-examination test specimens for T, K and Y joints and tested in accordance with Ch 12, 2.7 Destructive tests for steel butt welds 2.7.8.

Figure 12.2.16 Location of macro-examination test specimens for T, K and Y joints

2.9.3 A Vickers hardness survey is to be performed on the macro-section removed from position ‘A’ or ‘C’ in accordance with that shown in Figure 12.2.17 Hardness test locations for T, K and Y joints using a test load not exceeding 10 kg.

Figure 12.2.17 Hardness test locations for T, K and Y joints

2.10.1 Pipe branch welds may be by either full penetration, partial penetration or fillet welded, depending on the application and the approved plans. Where these types of welded joints are used, tests are to be performed which simulate the construction conditions.

2.10.2 The test weld assembly is to simulate the smallest angle between the branch and main pipe and is to be subjected to macro-examination and hardness testing, as follows:

1. For a branch weld that is full penetration, testing is to be performed in accordance with the requirements for ‘T', ‘K’ and ‘Y’ joints in Ch 12, 2.9 Destructive tests for T, K, Y steel nozzle welds.

2. For a branch weld that is either a partial penetration or fillet weld, testing is to be in accordance with the requirements for fillet welds in Ch 12, 2.8 Destructive tests for steel fillet welds.

2.11.1 Where weld cladding or overlay is allowed by Ch 13 Requirements for Welded Construction, and is considered as providing strength to the component to which it is welded, the type and location of test specimens are to be in accordance with Figure 12.2.18 Type and location of test specimens for weld cladding, except that micro-sections are not required. Impact tests may be omitted where the base material does not have specified impact properties. The longitudinal tensile and bend tests are to be tested in a similar manner to transverse specimens specified in Ch 12, 2.7 Destructive tests for steel butt welds 2.7.2 and Ch 12, 2.7 Destructive tests for steel butt welds 2.7.6, respectively.

Figure 12.2.18 Type and location of test specimens for weld cladding

2.11.2 Where the weld cladding is not considered as contributing to the strength of the component, but is required for corrosion or wear resistance, the type and location of test specimens are to be in accordance with Figure 12.2.18 Type and location of test specimens for weld cladding, except that tensile and impact tests are not required.

2.11.3 Where the weld cladding is applied for corrosion resistance, in addition to the above, weld metal analysis is to be performed on one of the micro-sections, on the final weld surface but 2 mm deep. The analysis is to be within the limits specified for the corrosion resistance required.

2.12.1  Longitudinal all weld metal tensile test:

1. In general, the longitudinal all weld tensile test is to meet the minimum properties specified in Table 11.3.2 Requirements for deposited metal tests (covered electrodes) or Table 11.4.2 Requirements for deposited metal tests (wire-flux combinations), as appropriate to the grade of steel and welding process used in the test.

2. Where the application is such that no consumable approvals are specified in Ch 11 Approval of Welding Consumables, the longitudinal all weld tensile test tensile is to meet the minimum properties specified for the base materials used in the test.

3. For pressure vessels manufactured from carbon or carbon/manganese steels, the tensile strength from the longitudinal all weld tensile test is not to be less than the minimum specified for the plate material and is not to be more than 145 N/mm² above this value,see Ch 13, 4.8 Mechanical requirements 4.8.3.

4. For tanks intended for liquefied gases, the weld metal strength may be lower than the minimum specified for the base metal provided that the application has design approval. In such cases the strength is not to be less than that specified in the approved design.

5. For base metal grades with minimum specified yield strength level of 890 and 960 N/mm², the weld metal strength may be lower than the minimum specified for the base metal provided that the application has design approval for the undermatching weld metal. In such cases the weld metal strength is not to be less than that specified in the approved design.

2.12.2  Transverse tensile test: The tensile strength measured from the transverse tensile test is not to be less than the minimum specified for the base material used in the test. For tanks intended for liquefied gases and for other types of assemblies for base metal grades with minimum specified yield strength level of 890 and 960 N/mm², a lower ultimate tensile may be accepted subject to design approval as in Ch 12, 2.12 Mechanical test acceptance criteria for steels 2.12.1.(d) and Ch 12, 2.12 Mechanical test acceptance criteria for steels 2.12.1.(e).

2.12.3  Bend tests:

1. In general, bend tests are to exhibit no defects exceeding 3,0 mm measured in any direction across the tension face of the specimen after being bent over the required diameter of former to the appropriate angle.

2. Bend tests for pressure vessel applications are to exhibit no defects exceeding 3,0 mm measured along the specimen or 1,5 mm measured transverse to the specimen axis, after bending.

3. In all cases, premature failure of the bend tests at the edges of the specimen is to not be cause for rejection unless these are associated with a weld defect.

2.12.4  Impact toughness tests:

1. Impact test specimens for hull construction are to be tested at the temperature, and are to achieve the minimum impact energy, as specified in Table 12.2.2 Impact test requirements for butt joints (t ≤ 50 mm) see Notes 1 and 2 and Table 12.2.3 Impact test requirements for butt joints (t > 50 mm) see Notes 1 and 2 .

2. Impact test specimens for applications other than hull construction are to be tested at the same temperature and achieve the same minimum energy values, as specified for the base materials used in the test.

3. Impact test acceptance criteria are to be in accordance with the above unless the Rules applicable to the particular construction specify more stringent requirements.

4. For quench and tempered steels, the required test temperature and absorbed energy are to be in accordance with that specified for the parent materials. For base metal grades with minimum specified yield strength level of 890 and 960 N/mm², the weld metal absorbed energy may be lower than the minimum specified for the base metal provided that the application has design approval for the undermatching weld metal. In such cases the absorbed energy is not to be less than that specified in the approved design.

2.12.5  Macro-examination:The macro-section is to reveal an even weld profile blending smoothly with the base material. The weld dimensions are to be in accordance with the requirements of the pWPS and any defects present are to be assessed against the non-destructive examination acceptance criteria given in Ch 12, 2.5 Non-destructive examination (NDE) 2.5.5.

2.12.6 Hardness surveys:

1. The maximum hardness value is not to exceed 350 Hv for steel grade EH47 and 380 Hv for steel grades EH47-BCA1 and EH47-BCA2.
2. For all other steel grades, themaximum hardness value is not to exceed 350 Hv for steels with a specified minimum yield strength up to ≤420 N/mm², nor exceed 420 Hv for steels with a specified minimum yield strength in the range 420 N/mm2 t o690 N/mm².

2.12.7  Weld fracture or break tests (for pressure vessel test welds): The faces of the broken fillet weld fracture or weld break test are to be examined for defects and assessed in accordance with the non-destructive acceptance criteria given in ISO 5817 Level B, except for excess convexity and excess throat thickness where Level C will apply.

2.13.1 Where a tensile, bend or hardness specimen fails to meet requirements, further test specimens may be removed and tested in accordance with the requirements of Ch 2, 1.4 Re-testing procedures 1.4.1.

2.13.2 Where an impact specimen fails to meet requirements, a further set of three specimens may be removed and tested in accordance with the requirements of Ch 2, 1.4 Re-testing procedures 1.4.4.

2.13.3 Where a macro specimen reveals a defect that is planar in nature, the welding procedure test is to be considered as not satisfying the requirements and a new test assembly is required.

2.13.4 Where a macro specimen does not meet requirements as a result of a volumetric imperfection exceeding the permitted size, two additional specimens may be removed from the same test weld and examined. If either of these macro-sections also fails to satisfy the requirements, the welding procedure is to be considered as not having met the requirements.

2.13.5 If there is a single hardness value above the maximum values specified, additional hardness tests are to be carried out, either on the reverse of the specimen, or after sufficient grinding of the tested surface. None of the additional hardness values is to exceed the maximum hardness values specified, otherwise the welding procedure is to be considered as not having met the requirements.

2.13.6 Where there is insufficient material available in the welded test assembly to provide re-test specimens, subject to prior agreement with the Surveyor, a second assembly may be welded using the same conditions as the original test weld.

2.14.1 The procedure qualification record (PQR) is to be prepared by the manufacturer and is to include details of the welding conditions used in the test specified in Ch 12, 2.2 Welding variables and the results of all the non-destructive examinations and destructive tests, including re-tests.

2.14.2 Provided that the PQR lists all the relevant variables and there are no inconsistent features and the results satisfy the requirements, the PQR may be endorsed by the Surveyor as satisfying the requirement of the Rules, see also Ch 12, 1.1 General 1.1.4.

2.15.1 A welding procedure qualification test that has successfully met the requirements may be used for a wider range of applications than those used during the test.

2.15.2 Changes outside of the ranges specified are to require a new welding procedure test.

2.15.3 Other ranges of approval from those specified in this Section may be agreed with the Surveyor, provided that they are in accordance with recognised National or International Standards.

2.15.4  Manufacturer. A welding procedure qualified by a manufacturer is valid for welding in workshops under the same technical and quality management.

2.15.5  Welding process and technique. The welding process and welding techniques approved are to be those employed during the welding procedure qualification test. Where multiple welding processes are used, these are to be employed in the same order as that used in the welding procedure qualification test. However, it may be acceptable to delete or add a welding process where it has been used solely to make the first weld run in the root of the joint, provided back gouging or grinding of the root weld is specified on the WPS. For multi-process procedures, the welding procedure approval may be carried out with separate welding procedure tests for each welding process.

2.15.6  Welding positions. Approval for a test made in any position is restricted to that position. To qualify a range of positions, test assemblies are to be welded for the highest heat input position, and the lowest heat input position, and all applicable tests are to be made on those assemblies. The above excludes welding in the vertical position with travel in the downward direction which will always require separate qualification testing and only be acceptable for that position.

2.15.7  Joint types. A qualification test performed on a butt weld may be considered acceptable for fillet and partial penetration welds, provided the same welding conditions are used. The range of approval depending on the type of joint for butt welds is given in Table 12.2.4 Range of approval for different types of butt joints.

2.15.8  Range of material types:

1. For normal and higher strength steels, for each strength level, welding procedures are considered applicable to the same and lower toughness grades as that tested. For each toughness grade, welding procedures are considered applicable to the same and two lower strength levels as that tested with the exception of the two-run (T) or high welding heat input (A) techniques where acceptance is limited to the strength level used in the test.

2. A qualification test performed on H47 strength grade steels may be used to weld the steel of the same strength level or grade H40 and all lower toughness grades to that tested.

3. The range of approval for the crack arrest steel grades is shown in Table 12.2.5 Range of approval for crack arrest steel grades. Welding procedures qualified on non-brittle crack steel grades are also considered applicable to corresponding brittle crack arrest steel grades where production heat input does not exceed 50 KJ/cm. For higher heat input, the welding procedures are to be qualified on crack arrest steel grades.

   Guidance: As an example, the corresponding crack arrest steel grades for non-brittle crack arrest steel grade EH40 are EH40-BCA1 and EH40-BCA2.

4. For high strength quenched and tempered steels, for each strength level, welding procedures are considered applicable to the same and lower toughness grades as that tested. For each toughness grade, welding procedures are considered applicable to the same and one lower strength level as that tested. The approval of quenched and tempered steels does not qualify thermo-mechanically rolled steels (TMCP steels) and vice versa.

5. For weldable C and C-Mn steel forgings, welding procedures are applicable to the same and lower strength level as that tested. The approval of quenched and tempered steel forgings does not qualify other delivery conditions and vice versa.

6. For weldable C and C-Mn steel castings, welding procedures are applicable to the same and lower strength level as that tested. The approval of quenched and tempered steel castings does not qualify other delivery conditions and vice versa.

7. Dissimilar materials. Where a qualification test has been performed using dissimilar materials, acceptance is to be limited to the materials used in the test.

2.15.9  Thickness and diameter range:

1. For straight butt welds, the material thickness range to be approved is to be based on the thickness of the test piece and the type of weld as shown in Table 12.2.6 Welding procedure thickness approval range - Butt welds.

2. For butt welds between plates of unequal thickness, the lesser thickness is the ruling dimension.

3. For fillet welds and ‘T’ butt welds, Table 12.2.6 Welding procedure thickness approval range - Butt welds is to be applicable to both the abutting and through member thicknesses. In addition to the requirements of Table 12.2.6 Welding procedure thickness approval range - Butt welds, the range of approval of throat thickness ‘a’ for fillet welds is to be as follows:

   • single run: 0,75a to 1,5a
   • multi-run: as for butt welds with multi-run (i.e. a =t)

4. Notwithstanding any of the above, the approval of maximum thickness of base metal for any technique is to be restricted to the thickness of the test assembly if three of the hardness values in the heat affected zone are found to be within 25 Hv of the maximum permitted.

5. The material diameter range to be approved is to be based on the diameter of the test piece and type of weld as shown in Table 12.2.7 Diameter range approved.

2.15.10  Welding consumables:

1. For manual and semi-automatic welding used for the fill and capping weld runs, it may be acceptable to change the brand or trade name of the welding electrode or wire from that used in the test, provided the proposed alternative has the same or higher approval grading and the same flux type (e.g. basic low hydrogen, rutile, etc.) as used in that test.

2. For the consumable used to make the root weld of full penetration butt welds made from one side only, no change in the type or trade name of the consumable or backing material is permitted. Alternative backing materials may be used provided they are equivalent to those used for approval. Where the approved backing material is a low hydrogen grade and the steel being welded requires a low hydrogen backing material, testing of the alternative backing material is to confirm compliance with the requirements of Ch 11, 7 Consumables for use in one-side welding with temporary backing materials.

3. For processes with heat input over 5 kJ/mm, no change in the type or trade name of the consumable is permitted.

2.15.11  Shielding gas. For gas shielded welding processes, a change in shielding gas composition from that used in the test will require a new qualification test.

2.15.12  Heat Input. The upper limit of heat input approved is 25 per cent greater than that used in the test, or 5,5 kJ/mm, whichever is the smaller. With heat input over 5,0 KJ/mm, the upper limit is 10 per cent above that used in the test. In all cases, the lower limit of heat input approved is 25 per cent lower than that used in the test.

2.15.13  Current type. The current type used during the qualification test is to be the only type approved. Additionally, changes from or to pulsed current require new qualification tests.

2.15.14  Preheat temperature. The temperature used during the test is to be the minimum approved. Higher temperatures may be specified for production welds up to the maximum interpass temperature. Where hardness tests have been performed that exhibit results near the maximum permitted, an increase in preheat temperature is required when welding material of greater thickness than that used in the test.

2.15.15  Interpass temperature. The maximum interpass temperature recorded during qualification testing is to be the maximum approved. Lower temperatures may be specified for production welding, but no lower than the minimum preheat temperature.

2.15.16  Post-weld heat treatment. A qualification test performed with no post weld heat treatment is only acceptable for production welding where no heat treatment is applied. Where the qualification test has included a post weld heat treatment, this is to be applied to all welds made with the welding procedure. The average specified soak temperature may vary by up to 25°C from that tested.

2.15.17  Shop primers. Welding procedure qualification with shop primers qualifies welds without primer, but not vice versa.

2.16.1 A welding procedure specification (WPS) is to be prepared by the manufacturer detailing the welding conditions and techniques to be employed for production welding. The WPS is to be based on the conditions and variables used during the qualification test, and is to include all the ranges of the essential variables specified in Ch 12, 2.2 Welding variables 2.2.1 and Ch 12, 2.15 Range of approval.

2.16.2 The WPS should reference the procedure qualification record upon which it is based and is to be approved by the Surveyor prior to commencing production welding.