NB 47014: The issue of filler metal categories in welding procedure qualification
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According to 6.1.3.1 of NB/T 47014-2023, changing the filler metal category number requires re-conducting a welding procedure qualification, except when welding Fe-1 and Fe-3 base metals with filler metals of a higher strength grade in place of those of a lower strength grade. How should this sentence be understood? I also have a practical question: I conducted weld evaluation for high-strength applications; the base material was 16MnD+Q345E, using full TIG welding (wire type ER55-Ni1), with impact testing at -40 degrees Celsius ； Can this weld evaluation be applied to the base material 16Mn+Q345D (with a shock temperature of -20°C), welded using TIG welding (with wire type ER50-6)? I originally thought that using filler metal with a higher strength level could compensate for filler metal with a lower strength level, but after checking the standards again today, I feel like my understanding was wrong Should it be that after conducting a weld evaluation using filler metal of a lower strength grade, it is possible to skip the evaluation when using filler metal of a higher grade?
Regarding the filler metal, the strength grade of the welding material used for the test specimens is high, while that used for the welded parts is low; therefore, it is not sufficient to cover the requirements.
Okay, thank you. I always find the sentences in these weld evaluation reports very difficult to understand; they’re prone to ambiguity
For example, in the case of the welding evaluation using J427 electrodes for Q245R material, it is possible to use J507 electrodes instead, provided that all other welding parameters remain unchanged