Under which condition is a "POR/WPS" essential variable required to be re-qualified when using FCAW?

A "POR/WPS" (Procedure Qualification Record/Welding Procedure Specification) is critical in ensuring that welding procedures are adequately documented and consistent with the requirements of the AWS D1.1 code. When considering the essential variables that necessitate a re-qualification when using Flux-Cored Arc Welding (FCAW), deletion of post-weld heat treatment stands out as particularly significant.

Post-weld heat treatment is a process used to reduce residual stresses and improve the mechanical properties of the weld joint. It can significantly affect the overall performance and integrity of the welded structure. If the original WPS included post-weld heat treatment as a requirement and this requirement is deleted, it directly alters the conditions under which the weld was qualified. This omission may lead to potential issues such as decreased toughness, increased susceptibility to cracking, or other detrimental effects that would compromise the structural integrity of the weld.

Thus, changing or removing any aspect that affects the mechanical properties of the final weld, particularly when it comes to heat treatment, mandates a re-evaluation and requalification of the welding procedure to ensure compliance with the necessary safety and performance standards outlined in the AWS D1.1 code.

In contrast, changes such as a decrease in base metal thickness, an increase or decrease