Valve welding inspection generally consists of following two parts:
1. Document review:
1.1 WPS(WELDING PROCEDURE SPECIFICATION), PQR, welder qualification WPQ;
1.2 Whether supplied WPS covers key variables such as parent material, welding material, welding method, groove form, thickness, preheating and post-weld heat treatment required by the order.
1.3 In accordance with WPS assessed by ASME volume 9 and NB/T47014, there are corresponding key variables in WPS; any key variable changed will lead to re-evaluation.
2. Inspection of field welding:
2.1 Usually VT (visual inspection) is used to check whether there are obvious welding defects on valves, such as cracks, nibbling, weld nodules, forming defects, burn-through, spatter, etc.
2.2 PT is usually used to check whether there is any crack on the welding sealing face.
2.3 Soldering of the seat and body requires a smooth appearance, no undercut, dislocation or overlap.
2.4 RT or UT checking internal quality for structural welding such as valve with extension nipples will be performed when order is required.