Effect of Welding Residual Stresses on Ductile Tearing of Austenitic Stainless-Steel Pipes by Local Approach

Abstract Welding residual stresses are caused by differential thermal expansion and effect of contraction of the weld metal and base metal. Self-balanced by nature, residual stress levels in and near the weld can be very high, up to material yield strength magnitude in highly constrained situations, which is the case in most structures. This stress level could have a non-negligible impact on fracture mechanics assessments (FMA). In this context, global approach through Rice’s integral can be used to estimate this impact but leads to an overestimation of the energy release rate if the energy generated by residual stresses is added to other loading ones. Consequently, local approach is an alternative candidate to assess more accurately the impact of residual stresses on fracture mechanics assessments. In the frame of the European Atlas+ project, tensile tests as well as four points bending tests have been performed on a welded austenitic stainless-steel material, which allow the determination of a set of parameters of Gurson-Tvergaard-Needleman (GTN) model. On this basis, we show in this work that the effect of residual stresses at the level of the yield strength of the base metal, on ductile tearing of austenitic stainless-steel pre-cracked pipes, vanish at the ductile tearing initiation.