Numerical and experimental investigation of the formation mechanism and the distribution of the welding residual stress induced by the hybrid laser arc welding of AH36 steel in a butt joint configuration

Abstract

Formation mechanism of the welding residual stress (WRS) is a key part of welding research. However, there is a lack of meaningful numerical models of the WRS. In this work, a thermal-metallurgical-mechanical (TMM) model was developed using SYSWELD to investigate the distribution and the formation mechanism of WRS during the hybrid laser arc welding of AH36 steel. A series of simulations were conducted to explore the effects of various factors on the WRS. The numerical results matched well with the experimental data. The computational accuracy was improved by considering the typical “wine glass” weld profile and the dilution rate during simulation. The evolution of the WRS is strongly affected by the interaction of phase transformation and strain hardening. The austenite-martensite transformation has a great potential to reduce the WRS whereas the austenite-bainite transformation produces high levels of WRS. The phase transformation temperature has a great influence on WRS.