Investigation of Laser Butt Welding of AISI 304L and Q235 Steels Based on Numerical and Experimental Analyses

The fiber laser butt welding of AISI 304L and Q235 low-carbon steel is performed in this study. An integrated heat source combined with an asymmetric double-ellipsoidal heat source and a cylindrical heat source is designed to perform the numerical simulation of the laser butt welding process. With the established numerical simulation model, the formation of the welded joint is studied by investigating the thermal process. The effects of the laser power and laser beam offset to the sides of the center of the welding gap on the welded joint shape and strength are experimentally investigated, and the optimum laser power and laser beam offset are determined via tensile strength and hardness tests of the weldment. The numerical simulation results based on the asymmetric heat source agree well with the experimental results and are applied to investigate the mechanisms for forming different welded joint shapes in AISI 304L and Q235 steels. The different thermal conductivity and melting temperatures of the two dissimilar metals result in the different shapes of the welded joint