Is heat treatment required for TP347 pipes after welding?
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Is heat treatment required for TP347 pipes after welding in high-pressure hydrogenation units? If necessary, what is an appropriate temperature control level?
1. In principle, heat treatment is not required. 2. If heat treatment is necessary, ASME B31.3 shall be followed; heat treatment is required only for stainless steels with a certain wall thickness. ASME B31.3 contains a table indicating the wall thicknesses at which heat treatment is needed – please check it
Whether stabilization heat treatment is required depends on the requirements of the design documents; the standards do not mandate such treatment； The stabilization heat treatment temperature shall be determined in accordance with the requirements of the SH3523 standard.
No heat treatment is required for hydrogen service conditions. . . . Are you sure?
Yes, but the weld hardness needs to be controlled.
Clause 7.1, which specifies the conditions for post-weld stabilization heat treatment, in NB/T10068-2018 Standard for Heat Treatment of Welded Materials of Stainless Steel Pipes Containing Stabilizing Elements (effective as of March 2019), sets out requirements for TP347