Failure investigation of 321 stainless steel pipe to flange weld joint

Failure investigation was conducted on a refinery pipe-to-flange weld joint that suffered cracking. Both the pipe and flange are made of AISI 321 stainless steel. The flange was circumferentially welded to the pipe which is seam welded. The investigation revealed that both the circumferential and seam welds were in sound conditions, namely no evidences of sensitization, lack of weld penetration, and voids or porosities. Thus, welding practices...