Evolution of residual stress in dissimilar welded rotor joint of novel Ni-Fe-based/Ni-based superalloy during welding and heat treatment

In this study, the distribution and evolution of residual stress in large thick-walled welded rotor joint made of Ni-based and novel Ni-Fe-based alloys during welding and post-weld heat treatment (PWHT) are investigated by numerical simulation and verified experimentally. The results indicate that the final state of weld stress is related to weld shrinkage and local bending deformation. The axial stress on the outer surface after PWHT at 980°C exhibits a significant distribution of ‘compressive stress on the novel Ni-Fe-based alloy side and tensile stress on the Ni-based alloy side’, which was mainly related to the coefficient of thermal expansion mismatch, and an approximate prediction formula is proposed to describe the peak level of axial stress on the outer surface of PWHT.