Interaction of residual stress with mechanical loading in an austenitic stainless steel

Single edge notched bend, SEN(B), fracture specimens fabricated from AISI Type 316H austenitic stainless steel and containing a residual stress field were used to quantify the interaction of a residual stress field on subsequent fracture behaviour when the specimens were subjected to an applied load. Autogenous welding (where no additional filler material is used) was used to impart the residual stress field following a procedure which had been extensively characterised numerically and experimentally. Crack growth resistant curves were obtained for the specimens, and for similar specimens containing no residual stress field. It was observed that the residual stress field had negligible impact on the fracture behaviour of the specimens, in contrast to recently reported work which demonstrated a large influence of a residual stress field when the test specimens were fabricated from a ferritic steel. A numerical programme was conducted to consider the results in the context of a structural integrity assessment. The test results were assessed using both the procedures described in R6, a well-known structural integrity assessment procedure, and by explicit calculation of a modified J -integral via two-dimensional cracked body finite element analysis. It was shown that the assessments were pessimistic, all predicting an influence of the residual stress field on fracture when none was observed experimentally.