Generation and distribution mechanism of welding-induced residual stresses

Welding-induced residual stresses (WIRS) can have influence on the performance and service life of the welded structures. The present study experimentally and numerically investigates the reason and mechanism behind the generation and distribution of WIRS concretely. The results show that the thermal shrinkage process and phase transformation process are the main sources generating welding-induced longitudinal residual stress (sigma RS Nevertheless, except for these two processes, the quenching process would be another source producing transverse residual stress (sigma RST ). In the current work, it is found that the maximum sigma RSL generally reaches the yield strength (sigma y) of base metal (BM) at ambient temperature (TRT) for both transforming and non-transforming materials but located at different areas. In the single-pass weldments without external restraint, sigma RST profile on the top surface is usually always M-shaped for the non-transforming materials but W-shaped instead for the transforming materials. The distribution mechanism behind the M-shaped or W-shaped sigma RST profile is systematically clarified here.