Requirements related to low-temperature impact for steel used in low-temperature pipelines
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According to the standards shown in the diagram, the relevant standard is SHT 3059-2012, the Specification for Material Selection in Petrochemical Piping Design. There is a batch of pipes made of A333.Gr.6 on site, with a design temperature of -45°. In accordance with clause 6.2.3 of this standard, the base metal, as well as the weld metal and heat-affected zone, must undergo low-temperature impact tests in accordance with the relevant provisions of current standards. It can be done when the base material is available. When should the weld metal be tested? Or is it sufficient to have just one qualified weld procedure qualification?
Only one qualified welding procedure qualification is required
For welds made of this type of material, a welding procedure qualification is sufficient!
Personal opinion: First, prepare a welding procedure specification, cut out materials to make welding test pieces; after non-destructive testing shows satisfactory results, carry out impact tests on the welds and heat-affected zones using standard test pieces. Only once these tests are successful should a welding procedure qualification be prepared. Final batch welding
Surely, process evaluation comes first, followed by the product