Which change in filler metals requires requalification of the welding procedure?

A change in filler metal group is significant enough to necessitate the requalification of the welding procedure because different filler metal groups can vary widely in their chemical composition, mechanical properties, and metallurgical behavior. Each group may have different requirements for preheating, interpass temperatures, welding speed, and post-weld heat treatment. Because these factors directly affect the quality and integrity of the weld, the welding procedure must be requalified to ensure compliance with the standards and to maintain the desired weld performance.

The other scenarios, such as changing from one manufacturer to another or switching from E-6010 to E-6010-5P, typically do not require requalification. This is because the base specifications for these electrodes fall within the same filler metal group. Performance characteristics, while potentially differing subtly between manufacturers, generally remain similar enough that requalification is not mandated. Therefore, it's only the more substantial change in filler metal groups that impacts the welding procedure's validity and necessitates requalification.