Preheating before welding
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This post was last edited by jacques0920 on 2015-9-9 16:39. Hello everyone, what types of pipes need to be preheated before welding? What is the purpose again?
This post was last edited by ylb913 on 2015-8-31 at 15:35. I know it’s chrome-molybdenum steel; I can’t explain exactly why, but it tends to crack easily. The requirements for this pre-welding heat treatment are specified in SH 3501-2002, the Construction Code for Pipelines Transporting Toxic and Flammable Media in the Petrochemical Industry.
I remember there was an explanation in the forum regarding this issue: Both chromium-molybdenum steel and low-temperature steel require heat treatment before and after welding. Pre-welding heat treatment is primarily used to improve the weldability of the material, reduce the temperature difference in the welding area, and minimize the tendency for hardening.