Under what circumstances is post-weld heat treatment necessary, and what standards should be followed for the heat treatment requirements?
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Under what circumstances is post-weld heat treatment necessary, and what standards should be followed for the heat treatment requirements?
Heat treatment is generally used to eliminate internal stresses. The preheating range for low-alloy and high-alloy steels is generally determined based on the material type; therefore, low-carbon steel with a thickness of over 30 requires heat treatment, as thicker plates generally have greater internal stresses ； Low-alloy steel requires preheating at 0 degrees ； Preheating is also required when welding carbon steel with a thickness of over 30 mm.
Is there any standard mentioning this? ?
Take a look at SH3501
This is a fairly large issue, involving equipment and pipelines. Under what circumstances do general design and manufacturing standards require heat treatment?
For pipes, refer to GB20801.4; for equipment, refer to GB150.4