Generation and distribution mechanism of welding-induced residual stresses

Abstract

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 (σLRS). Nevertheless, except for these two processes, the quenching process would be another source producing transverse residual stress (σTRS). In the current work, it is found that the maximum σLRS generally reaches the yield strength (σy) 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, σTRS 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 σTRS profile is systematically clarified here.

Keywords

• Welding-induced residual stresses
• Longitudinal residual stress
• Thermal shrinkage process
• Phase transformation process
• Transverse residual stress
• Quenching process