Study on weld shaping and organizational properties of laser circular oscillation welding of 5A06 aluminum alloy

In this paper, a combination of simulations and experiments was used to systematically study the nonoscillation and circular oscillation laser welding techniques and the comprehensive effects of varying laser powers on weld geometry, temperature fields, molten pool flow, and the microstructure of the 5A06 aluminum alloy. The results of this study demonstrate that the circular oscillation technique significantly reduces weld spatter while optimizing the quality of the weld formation. At a laser power of 2850 W, the surface finish of the weld is maximized, exhibiting a smooth and continuous morphology. Fluent simulation analysis indicates that the circular oscillation promotes a more uniform temperature field distribution, which facilitates the formation of a wide and shallow molten pool. Furthermore, the temperature field during the welding process reveals the evolution of the “circular-elliptical-fusiform” pattern. Circular oscillating welds exhibit an asymmetric shape, characterized by a higher left side and a lower right side due to path differences. The weld depth-to-width ratio initially increases before decreasing as laser power increases. A moderate increase in laser power caused the precipitated phase to shift from a diffuse to a striated distribution; however, excessive laser power resulted in the melting and dilution of the precipitated phase. This study provides a theoretical foundation for optimizing the laser welding process and selecting appropriate process parameters.