Issues related to weld replacement in GB/T 150.4
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Articles 6.1.6 and 6.4.7 of 150.4 both relate to the replacement of welds in components that are first welded together and then heat-formed. Can it be understood that for such welds, if a product welding test piece is not created to prove that the welds are qualified, then the welds must be replaced?
Yes, according to clauses 6.1.6 and 6.4.7 of GB/T 150.4, for components that are first welded together and then heat-formed, if no welding test pieces are created to verify the quality of the welds, then weld replacement is required. .
Before the implementation of 150-2024, no standard contained such a requirement; if this rule is followed, would it mean that all pressure components that are heat-formed after welding must have welding test pieces manufactured? Materials like Q245R and Q345R are, in the vast majority of cases, a waste of resources. The standards are too vague and one-size-fits-all!
Clause 3.17 of GB150.4 specifies that first, a welding material is used to weld the joint; after hot pressing to give it shape, the metal from that weld is removed, and then welding is performed again.
Under the new standards, if no replacement is made, it is necessary to use product test plates to verify the performance of the welds.
According to GB/T150.4-2024, clauses 6.1.6 and 6.4.7, for end caps made by thermoforming and splicing, if process evaluation is available, test plates must be fabricated; otherwise, weld replacement is required
This results in a large number of test plates, especially for end caps; previously, those formed by hot pressing with seams did not have any test plates at all. With ordinary Q245R and Q345R materials, no problems have arisen either.
For ordinary end caps in the future: laminated plates + cold forming + stress relief – is that how it will be done?
I need to study the technical specifications for ordering end caps carefully.
A forming temperature should be set; specimens that exceed the upper transition temperature or for which it is necessary to restore material properties need to be replaced or taken out. Generally, for thin sheet forming at lower temperatures, weld replacement and welded test pieces are not necessary.