Regarding the issue of substituting weld evaluations
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There is a statement in NB/T47014 that a welding process deemed suitable for a certain base material is applicable to other base materials of the same category and group”； So can it be understood that the weld evaluation for 304 can replace that for 316L? Why? Since the pipeline welding on site currently involves welding of dissimilar steels such as 321H and GB9948, can I use any weld evaluation for the dissimilar steel welding specified in NB/T47014, namely Fe-8-1 and Fe-1-1, to replace the former?
Different types of weld qualification reports cannot be used interchangeably, as base materials of different materials have varying chemical compositions, mechanical properties, and other characteristics, requiring different welding processes. Even though they are both stainless steels, 304 and 316L differ from each other, so their welding evaluations cannot be used interchangeably. For the on-site welding of 321H and GB9948 dissimilar steels, the relevant provisions for welding Fe-8-1 and Fe-1-1 dissimilar steels in NB/T47014 can be referred to; however, reasonable adjustments and verifications must be carried out based on actual conditions to ensure that the welding quality meets the required standards. .
Same question: Welding evaluation for 304 and 304L
1. In principle, materials that have passed the 304 evaluation can be used for 316L, in accordance with item b of 6.1.2.2 in NB/T47014； Be sure there are no other requirements. 2. The welding evaluation procedures for the dissimilar steel grades Fe-8-1 and Fe-1-1 specified in NB/T 47014 are not applicable to all steel types listed in GB 9948; they are only applicable to the welding of dissimilar steels consisting of stainless steels and high-quality carbon steels as defined in GB 9948 ； Item a of 6.1.2.1 in NB/T47014.
They belong to the same category and group; welding evaluation for just one type of material is sufficient； Item b of 6.1.2.2 in NB/T47014.
Different welding materials are used for 304 and 316; changing the welding material requires a new weld assessment to be conducted
The welding materials belong to the same group as well, so they can be used interchangeably without any problem