Impact sampling at the isolation layer location
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Dear teachers, the draft of the new version of NB/T47014-20XX states that for weld evaluations involving an insulating layer, a separate impact test sample must be taken from that insulating layer (see Screenshots 1 and 2). So, when taking an impact test sample from the insulating layer, how should the notch position on the sample be located within that insulating layer? (For impact specimens taken from the heat-affected zone, standard NB/T47014 specifies that K>0 is required to determine the location of the notch in such specimens within the heat-affected zone; but for impact specimens taken from the isolation layer, how is the notch location determined?) Are there any provisions in the ASME and API standards that address such situations? Are there any other guidelines to follow?
The draft of the new version of NB/T47014-20XX does not specify a precise method for locating the notch where the impact test sample is taken in the isolation layer. The ASME and API standards also do not specify this situation in detail. Generally, the notch for impact testing should be located in the central area of the insulation layer, avoiding any welds or heat-affected zones. The specific sampling location can be determined based on the specific conditions of the welded structure and the engineer’s experience. If there are no specific guidelines, it is recommended to consult experts in welding standards or relevant technical organizations. .