Effect of Strain Hardening Constitutive Relations on Weld Residual Stress Simulation of Dissimilar Metal Weld

Weld residual stress (WRS) in dissimilar metal welds (DMWs) has been identified as an important driver for primary water stress corrosion cracking, which is observed in nuclear power plant safety-related components. In this work, a newly developed dynamic strain hardening rule is implemented in finite element (FE) thermal-mechanical model to simulate the residual stress distribution in a dissimilar metal weld studied in a recent NRC/EPRI Round Robin study. This new dynamic strain hardening constitutive rule takes into account the effect of dynamic recovery and recrystallization at elevated temperatures on the strain hardening behavior during welding. Weld residual stresses calculated using the new dynamic strain hardening rule are compared to those with the conventional strain hardening ones (isotropic and kinematic), as well as the experimental measurement data. The new dynamic strain hardening rule results in improvements in WRS prediction.