Prediction of residual stress and elasto-plastic strains distribution in disk keyhole laser welding of dissimilar joining between copper & 304 stainless steel

In this study, a simulation is developed for dissimilar metal sheets followed by a numerical model for laser welding. The continuous disk laser welding process for dissimilar joining between 304 stainless steel and copper is simulated. For this purpose, double conical heat source distribution model was implemented into Abaqus/Standard solver using additional DFLUX subroutine written in the FORTRAN programming language in order to estimating the temperature distribution, prediction the geometry and dimensions of weld cross section including the fusion zone (FZ) and heat affected zone (HAZ). The weld joint output parameters such as temperature, strain distribution, residual stresses and weld geometry were examined. The validation of the simulation output results were confirmed by comparison with the experimental results by other researchers at three level with three input parameters. The results showed that copper, due to the higher thermal conductivity during cooling, passed through more heat at the same period of time, so these results lead to lower temperature in the center of FZ and a smaller HAZ in this dissimilar welding in comparison to similar welding. After cooling time, longitudinal residual stresses in the FZ for both materials were tensile also due to higher thermal expansion coefficient of steels, the quantity of stresses are 23% more than copper. The computed results are well agreed with experimentally measured values and show the robustness of the present numerical model used for dissimilar laser welding.