Investigation of laser welding processes for T-joint under varying workpiece inclinations

This study aims to investigate the impact of varying workpiece inclinations on the quality of laser welding and the performance of T-joints. Using 304 stainless steel as the study material, the influence of process parameters—workpiece inclination, laser power, welding speed, and oscillation mode—on weld bead formation is analyzed. The results indicate a positive correlation between laser power and both the molten depth and the molten width of the weld pool. When the welding speed is high, incomplete fusion is observed in the workpiece. In the laser point oscillation mode, the molten depth and the molten width exhibit a parabolic variation, initially increasing and then decreasing. The influence of workpiece inclination on welding performance manifests as follows: under a point oscillation mode, the molten depth and the molten width initially increase and then decrease. In the ∞ oscillation mode, with an increase in the inclination angle, the molten width decreases, and the molten depth first decreases and then increases. In the circular oscillation mode, the molten width, the molten depth, and the transverse molten depth all show a trend of initially decreasing and then increasing. The workpiece inclination significantly affects both the grain growth direction and size, with noticeable coarsening of the grain structure as the inclination angle decreases from 30° to 15°. Hardness tests indicate that the hardness distribution is more uniform when the workpiece inclination is 15°. However, excessively large inclination angles may lead to an uneven heat input.