Numerical investigation of residual stress and welding deformation in S700MC/DP1180 dissimilar-metal butt-welded joint

This study proposed material models for the S700MC/DP1180 dissimilar-metal butt-welded joint, which accounts for solid-state phase transformation and tempering softening. Based on the models, a numerical approach was employed to calculate the welding-induced stress and deformation. After experimental verification, the calculated results demonstrate that solid-state phase transformation and softening effect significantly affect the magnitude and distribution of residual stresses: the peak longitudinal residual stress shifts from the DP1180 side to the S700MC side, decreasing from 1092 to 798 MPa; the location of the peak transverse residual stress is also relocated, and its magnitude declines from 162 to 111 MPa. Although the solid-state phase transformation and softening effect induce a slight reduction in welding deformation, their influence is marginal.