Optimization analysis of process parameters for laser spiral spot welding

Compared with resistance spot welding, laser welding possesses advantages such as faster welding speed, smaller deformation of welded parts, and higher shear strength. Although the laser spiral spot welding process involves numerous parameters, research on their optimization is currently limited. To obtain the optimal process parameters for robotic laser flight welding using spiral spot welding, numerical simulations of the energy distribution for different spiral trajectories were first conducted using MATLAB. Then, an orthogonal experiment was established to determine the process parameters for achieving the maximum shear strength of joints in laser spiral spot welding of DC01 and DC05 cold-rolled steels. The cross-sectional shape and microstructure of the joints were observed and analyzed, and finally, parameter optimization was performed based on joint shear strength, cross-sectional shape, and microstructure. The results indicate that the outer radius of the spiral line and the number of turns have the most significant influence on the shear strength and cross-sectional shape of the joint. A high surface energy density leads to material loss and grain coarsening.