Systematic approach to improve overlap laser welding of AA5052-H32 with dissimilar thickness by evaluation of mechanical performance, undercut, and welding penetration

AA5052 is a widely used aluminum alloy in the automotive industry due to its excellent weldability, mechanical properties, and corrosion resistance. This study aims to optimize the parameters for wobbling overlap laser welding of dissimilar thickness aluminum AA5052-H32 sheets. The investigated parameters include laser power, travel speed, focal position, oscillation shape, and oscillation amplitude. The results reveal that the oscillation pattern has a minimal effect on mechanical strength. Additionally, the power intensity range of 13.2–20 J/mm² has been identified to ensure that weld efficiency remains above 89.9%. However, considering the significance of the undercut value for achieving a smoother weld line, it is necessary to maintain the oscillation amplitude at a minimum value of 1.5 mm. The microhardness pattern proves to be a valuable method for detecting defects such as underlying porosities and deflection caused by excessive thermal input on the top sheet. The optimized processing parameters for 1–1.5 mm thickness aluminum AA5052-H32 are determined as 2500 W, 5 m/min, 6.0 mm, and 1.5 mm for laser power, travel speed, focal position, and oscillation amplitude, respectively.