Discussion on the evaluation of category groups in NB/T47014?
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12Cr1MoV and 15CrMo belong to the same category number; according to 6.1.2.1 c, welding between 12Cr1MoV and 15CrMo is suitable, as is welding between 12Cr1MoV and 20, or between 15CrMo and 20. According to 6.2.2.2 c, welding between 12Cr1MoV and itself is suitable for the welding of 12Cr1MoV and 15CrMo. I still can’t figure out the following questions. 1. Can the evaluation of 15CrMo+20 cover the evaluation of 12Cr1MoV+20? ? Or 2. Is there an evaluation for 12Cr1MoV+20? Can it cover the evaluation for 15CrMo+20? According to the rules of NB/T47014, can it cover it? Urgent! !
According to the standard understanding, it can be covered; dissimilar steels are category codes. However, the boiler and vessel manufacturers I have worked with are different; when choosing welding materials for boilers, they tend to opt for higher standards, while when selecting welding materials for vessels, they tend to go for lower standards.
The answer is no. According to the provisions of 47014, materials of the same category, such as 12Cr1MoV and 15CrMo, can be used for welding with materials of a higher grade once they have passed the evaluation for that grade; however, this does not apply to welding with materials of a lower grade, let alone welding with 20 steel.
This post was last edited by cheng83358 on 2016-7-4 at 15:13. The second option is acceptable, but it depends on the welding material you choose; when considering whether coverage exists between different groups within the same category, the welding material must be taken into account, refer to 6.1.3.1