What is the requirement for re-qualifying a PQR/WPS if there is a deletion of PWHT?

Requalification of a Procedure Qualification Record (PQR) and Welding Procedure Specification (WPS) is necessary when a key variable in the welding processes is altered. In this case, the deletion of post-weld heat treatment (PWHT) is significant since any changes that could affect the mechanical properties, the microstructure, or the overall integrity and performance of the welded joint require a re-evaluation.

PWHT is employed to enhance the weld quality by relieving residual stresses, improving ductility, and reducing the risk of cracking. Removing this treatment introduces potential risks that require validation through requalification.

Thus, the requirement aligns with the standard which stipulates that any modification to essential variables that may affect the quality and performance of the weld necessitates requalification to ensure compliance with the AWS D1.1 guidelines. This ensures that the welding practices remain consistent with the expected performance criteria and safety standards after any changes.