Welding of dissimilar steel materials in pipelines

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This post was last edited by water20042005 on 2023-5-9 10:11. Dear seniors, I would like to ask whether carbon steel flanges for pressure pipelines (20II) can be welded to stainless steel seamless pipes (S30408)? If welding is possible, are there any corresponding requirements for heat treatment, flaw detection, etc.? Can SHT3526-2015 be used as a reference for implementation? (Is grade 20II forgings a ferritic steel?) Which specification needs to be consulted? Thank you. 1.GB50236-2011 7.3.1 The selection of welding materials shall be determined comprehensively based on factors such as the chemical composition, mechanical properties, weldability of the base metal, pre-welding heating, post-welding heat treatment, operating conditions, and construction conditions, and shall comply with the following provisions: 4 For welding of dissimilar steels, the following provisions shall apply: 2) When one of the two base metals is an austenitic steel, welding materials of the 25Cr-13Ni type or those with a higher nickel content shall be selected. When the design temperature is above 425°C, nickel-based welding materials are recommended. II. Appendix D of HG/T20581-2011 (informative appendix): Table for selecting welding materials for dissimilar metals such as carbon steel, stainless steel, and nickel-based alloys. The wire types listed in SFA-5.14 for inert gas shielded welding of stainless steel and carbon steel are ERNiCr-3/ERNiCrFe-6 ； For stainless steel and carbon steel, the electrode types specified in SFA-5.11 for shielded metal arc welding are ENiCrFe-2/ENiCrFe-3 ； III. SH/T3526-2015 1 Scope This standard applies to the welding of dissimilar steel welded joints in petrochemical, coal chemical, and natural gas chemical equipment and pipelines, using processes such as shielded metal arc welding, tungsten inert gas welding, gas metal arc welding, and submerged arc welding. The welding of dissimilar steels specified in these standards includes: a) welding of different ferritic steels; b) welding of different austenitic stainless steels; c) welding of ferritic steels and austenitic stainless steels; d) surfacing welding for wear and corrosion resistance.