NB/T47014-2023 Appendix E
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Appendix E of the new version 47014-2023 includes test pieces for the weld qualification of heat exchange tubes and tube sheets, such as fillet weld test pieces, butt weld test pieces, and simulated assemblies. For example, if the thickness of a tube sheet is 100 mm and a 2×45° groove is made in it, with the heat exchange tubes having dimensions of 2.0 mm × φ25 mm, then when using butt welding for qualification, is it necessary to take into account the range of base metal thicknesses?
According to Appendix E of NB/T 47014-2023, when conducting process qualification for butt welds, the range of base metal thicknesses must be taken into consideration. Even when there is a large difference in the thicknesses of the heat exchange tubes and the tube sheet, the butt weld specimens should simulate the actual welding conditions, ensuring that the thickness of the base material of the specimens covers the actual welding area in order to guarantee the validity of the evaluation results. Therefore, even if the tube sheet thickness is 100 mm, the thickness of the tube sheet in the butt weld test piece must also be sufficient to represent the thickness of the actual welding area; it cannot simply be 100 mm. .
I understand that it is necessary to consider the range of base material thicknesses
For the butt welding process evaluation, only the groove of the tube sheet (2mm) and the thickness of the heat exchange tubes are considered.
According to this, using the corresponding PQR will suffice.