Investigation of Weld Failure in Superaustenitic UNS S31245 Stainless Steel

摘要

During the course of evaluating seam weldedUNS S31254 superaustenitic stainless steel piping it was foundthat the parent metal gave up to 50percent tensile elongationvalues but some plasma-arc welded joints suffered weld metalcracking at elongation values as low as 10percent.Scanning electron microscopy showed that the weld metalfailed by low ductility, intercellular fracture along a network ofbrittle second phase particles having a composition similar tothat of sigma (a) phase. These particles were formed at the cellinterfaces by transformation of delta ferrite during the finalstages of solidification.