Predicting Welding Residual Stress of a Multi-pass P92 Steel Butt-Welded Joint with Consideration of Phase Transformation and Tempering Effect

A three-dimensional finite element model based on thermal-metallurgical-mechanical coupling theory was developed to simulate temperature field, phase fraction and residual stress distribution of a multi-pass P92 steel butt-welded joint. In the FE model, the influences of volume change, yield strength variation and plasticity induced by phase transformation on welding residual stress were carefully taken into account. In addition, an attempt was made to consider the effect of tempering on residual stress. In the current study, the hole-drilling method was employed to measure the residual stress distribution on the surface of P92 steel butt-welded joint, while optical microscope and Vickers hardness tester were used to characterize the microstructure and hardness, respectively. The comparison between the simulation results and the measured data shows that the developed computational approach could accurately predict welding residual stress for multi-pass P92 steel joint. Moreover, the results of Satoh test indicate that the tempering effect has influence on the stress evolution and the final magnitude to a certain extent.