Laser spiral spot welding process parameters optimization research

Compared to resistance spot welding, laser welding has advantages such as faster welding speed, smaller deformation of the welded parts, and higher shear strength. The laser spiral spot welding process has many parameters; however, there is currently limited research on the optimization of these parameters. To obtain the optimal process parameters for robotic laser flight welding using spiral spot welding, this paper first conducts numerical simulations of energy distribution for different spiral trajectories using MATLAB. Then, an orthogonal experiment is established to determine the optimal process parameters for achieving the best shear strength of joints when laser spiral stacking DC01 and DC05 cold-rolled steel. The joint's cross-sectional shape and microstructure are observed and analyzed, and finally, parameter optimization is performed from the perspectives of joint shear strength, cross-sectional shape, and microstructure. The results show that the outer radius of the spiral line and the number of turns have the greatest impact on the joint's shear strength and cross-sectional shape; a higher surface energy density can lead to material loss and grain coarsening. The optimized joint's shear strength is improved by 24% compared to resistance spot welding.