Formation of Hot Cracks in Austenitic Stainless Steel Welds — Solidification Cracking Crack formation is controlled by phase transformations and interfacial energy considerations

Solidification cracking in austenitic stainless steel welds was investigated by Spot-Varestraint tests using pure laboratory heats and commercial heats. The initiation and propagation of solidification cracks were found to be controlled by the formation of the solidification grain boundary, interfacial energy considerations, and the phase transformations occurring upon solidification. The ability to backfill the cracks also affects the extent of cracking observed in welds. The primary austenitic mode of solidification occurring in some of these alloys enables cracks to initiate and propagate more easily. This is further enhanced by sulfur segregation. The primary ferritic mode of solidification, however, inhibits crack initiation and propagation and promotes backfilling.