The Effect of Residual Stress on Fatigue Crack Growth of Multi-Pass Welds

The multi-pass welding generates residual stress which may change fatigue crack growth rate and impair the lifetime of nuclear welded structures. In this paper, we performed fatigue test with notched specimens and evaluate the effect of residual stress on fatigue crack growth rate of welds. In order to identify the magnitude of residual stress, the residual stress was measured by HDM (hole drilling method) and residual stress analysis was performed by using FEM (finite element method). In order to review the effect of residual stress on fatigue crack growth rate, the fatigue crack growth analysis was also performed to determine the fatigue crack growth curves by using FEM and ASME B&PV Code, Sec.XI, App.A. Finally, as a result of comparison among the fatigue crack growth curves, it is found that the fatigue crack growth rate was quite different according to the crack location even if the residual stresses are considered.