Section 8 Consumables for welding austenitic and duplex stainless steels
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Clasifications Register Rules and Regulations - Rules for the Manufacture, Testing and Certification of Materials, July 2022 - Chapter 11 Approval of Welding Consumables - Section 8 Consumables for welding austenitic and duplex stainless steels

Section 8 Consumables for welding austenitic and duplex stainless steels

Parent topic: Chapter 11 Approval of Welding Consumables

8.1 General

8.1.1 Tests for the approval of consumables intended for welding the austenitic and duplex stainless steels detailed in Ch 3, 7 Austenitic and duplex stainless steels are to be carried out generally in accordance with the Ch 11, 3 Electrodes for manual and gravity welding, Ch 11, 4 Wire-flux combinations for submerged-arc automatic welding, Ch 11, 5 Wires and wire-gas combinations for manual, semi-automatic and automatic welding, Ch 11, 6 Consumables for use in electro-slag and electro-gas welding or Ch 11, 7 Consumables for use in one-side welding with temporary backing materials relevant to the type of consumable or combination.

8.1.2 Approval will be indicated by the grade or grades of parent stainless steel for which the consumable or combination is approved.

8.1.3 Where a shielding gas is employed separate approval will be required for each specific shielding gas composition.

8.1.4 Consumables for welding the austenitic stainless steels and the duplex stainless steels to carbon or carbon-manganese steels will be approved in a similar manner. Parent plate used for the butt and fillet weld test assemblies will be carbon or carbon-manganese steel with either austenitic stainless steel or duplex stainless steel, as appropriate. Approval will be indicated by `SS/CMn' and `Dup/CMn' respectively, however, no buttering of test assembly plates is allowed for these two approvals.

8.1.5 Separate approval will be given for welding chemical and cryogenic applications. For chemical use, evidence of relevant corrosion resistance will be required. Charpy impact toughness tests will be required for all uses, but for cryogenic use the Charpy impact toughness requirements are more severe.

8.1.6 The welding technique will be indicated in the approval grading by a letter:

m = for manual SMAW or GTAW welding.
S = for wire-gas combinations used with a semi-automatic multi-run technique.
M = for wire-flux or wire-gas combinations used with an automatic multi-run technique.
T = for wire-flux or wire-gas combinations used with an automatic two-run technique.
A = as for M but using a procedure with a high heat input rate (large bead size relative to thickness welded). This would apply to welds made by four or less runs in 20 mm thickness, or eight or less runs in 35 mm.

8.2 Deposited metal test assemblies

8.2.1 Where the relevant Section requires deposited metal assemblies to be made and tested, the plates used must be either of the type for which approval is required or of normal strength carbon, or carbon-manganese steel with the prepared edges built up with stainless steel weld metal and finished with a layer of weld metal from the consumable to be approved.

8.2.2 The chemical analysis of the deposited weld metal is to be reported, including all significant elements. The elements reported will be dependent on the type of stainless steel for which approval of the consumables is requested. Any unusual weld metal compositions will have to be justified in respect of the particular approval requested. This is to be supplied by the manufacturer and is to include the content of all significant elements. The results of the analysis are not to exceed the limit values specified in the standards or by the manufacturer, the narrower tolerances being applicable in each case.

8.2.3 The results of all tensile and notch impact tests are to comply with the requirements given in Table 11.8.1 Requirements for deposited metal tests (manual, semi-automatic and automatic multi-run techniques) as appropriate.

8.2.4 The ferrite content in the last weld run from each deposited metal assembly is to be determined by physical or metallographic means, and reported, indicating the method of determination.

8.3 Butt weld test assemblies

8.3.1 Where the relevant Section requires butt weld assemblies to be made and tested, the plates used are to be either of the type for which approval is required or of steel having strength and ductility within the range specified for the grade to be approved. In the latter case, provided the consumable is metallurgically compatible with the base material to be used, the prepared edges are to be built up with a layer of weld metal before final machining of the weld preparation.

8.3.2 Butt weld assemblies are to be prepared for each position (downhand, horizontal-vertical, vertical-upward, vertical-downward, and overhead) for which the electrode/wire is to be approved.

8.3.3 The results of transverse tensile, notch impact and bend tests are to comply with the requirements of Table 11.8.2 Requirements for butt weld tests (all techniques) as appropriate. The position of fracture is to be reported to LR.

8.3.4 The ferrite content at the centre of the weld metal in each butt weld assembly is to be determined by physical or metallographic means, and meet the requirements in Table 11.8.2 Requirements for butt weld tests (all techniques). The method of determination is to be reported.

8.3.5 For austenitic and duplex stainless steel approvals (except for types 304L, 316L, 321, 347, SS/CMn and Dup/CMn), an appropriate sample from each butt weld assembly is to be submitted to the corrosion testing provided in ASTM G48, Method `C'. The results are to be reported so as to allow confirmation of the maximum acceptable pitting corrosion resistance temperature. This will be part of the approval grading and will be set at 5°C intervals. The minimum pitting corrosion temperature would not be expected to be less than 20°C.

8.4 Fillet weld test assemblies

8.4.1 Where the relevant Section requires fillet weld assemblies to be made and tested, the plates used must be either of the type for which approval is required or of steel having strength and ductility within the range specified for the grade to be approved. In the latter case, the surfaces on which the fillet weld beads are to be deposited are to be cut back by machining and then built up to original dimensions with weld metal from the consumable to be approved.

Table 11.8.1 Requirements for deposited metal tests (manual, semi-automatic and automatic multi-run techniques)

Grade 0,2% proof stress N/mm2 minimum 1% proof stress N/mm2 minimum Tensile strength N/mm2 minimum Elongation on 50 mm % minimum Charpy V-notch impact tests
Chemical test temperature °C Cryogenic test temperature °C Average energy See Note 1 J minimum
304L 270 310 500 25 -20 -196 29
304LN 305 345 530 22 -20 -196 29
316L 270 310 500 22 -20 -196 29
316LN 305 345 530 22 -20 -196 29
317L 305 345 530 22 -20 -196 29
317LN 340 380 570 22 -20 -196 29
321 290 330 550 22 -20 -196 29
347 290 330 550 22 -20 -196 29
S 31254 370 410 650 22 -20 -196 29
N 08904 270 310 500 22 -20 -196 29
SS/CMn 270 310 500 22 -20 -60 29
S 31260 485 525 690 20 -20 see Note 2 40
S 31803 450 490 620 25 -20 see Note 2 40
S 32550 550 590 760 15 -20 see Note 2 40
S 32750 550 590 800 15 -20 see Note 2 40
S 32760 550 590 750 25 -20 see Note 2 40
Dup/CMn 270 310 500 22 -20 see Note 2 40

Note 1. Energy values from individual impact test specimens are to comply with Ch 11, 1.4 Approval procedures 1.4.3.

Note 2. Approval for cryogenic applications is to be obtained at the procedure approval stage.

Table 11.8.2 Requirements for butt weld tests (all techniques)

Grade Tensile strength N/mm2 minimum Bend test ratio: Weld ferrite content % Charpy V-notch impact tests
Chemical test temperature °C Cryogenic test temperature °C Average energy (see Note 1) J minimum
304L 500 3 4-12 -20 -196 27
304LN 530 3 4-12 -20 -196 27
316L 500 3 4-12 -20 -196 27
316LN 530 3 4-12 -20 -196 27
317L 530 3 4-12 -20 -196 27
317LN 570 3 4-12 -20 -196 27
321 550 3 4-12 -20 -196 27
347 550 3 4-12 -20 -196 27
S 31254 650 3 (see Note 2) -20 -196 27
N 08904 500 3 (see Note 2) -20 -196 27
SS/CMn 500 3 4-12 -20 -60 27
S 31260 690 4 35-65 -20 (see Note 3) 40
S 31803 620 3 35-65 -20 (see Note 3) 40
S 32550 760 6 35-65 -20 (see Note 3) 40
S 32750 800 6 35-65 -20 (see Note 3) 40
S 32760 750 6 35-65 -20 (see Note 3) 40
Dup/CMn 500 3 (see Note 2) -20 (see Note 3) 40

Note 1. Energy values from individual impact test specimens are to comply with Ch 11, 1.4 Approval procedures 1.4.3.

Note 2. To be reported for special consideration.

Note 3. Approval for cryogenic applications is to be obtained at the procedure approval stage.

8.4.2 The ferrite content at the centre of the weld metal in each fillet weld bead of each assembly is to be determined from the centre macro-section by physical or metallographic means, and reported. The method of determination is also to be reported to LR.

8.4.3 Where approval is sought for fillet welding only, corrosion testing is to be carried out in accordance with Ch 11, 8.3 Butt weld test assemblies 8.3.5 from a sample taken from the deposited metal test assembly.

8.5 Annual tests

8.5.1 Annual tests are to be carried out as required by the relevant Section appropriate to the type of consumable and welding technique. The tests are to include a weld ferrite content in accordance with Ch 11, 8.2 Deposited metal test assemblies 8.2.4 or Ch 11, 8.3 Butt weld test assemblies 8.3.4 as appropriate.

8.5.2 The results of all tests are to comply with the requirements given in Table 11.8.1 Requirements for deposited metal tests (manual, semi-automatic and automatic multi-run techniques) and Table 11.8.2 Requirements for butt weld tests (all techniques) as appropriate.

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