Investigation of influence of oscillation amplitude on keyhole and molten pool morphologies during oscillating laser stake welding of dissimilar materials T-joints

The morphologies of the keyhole and molten pool during the laser welding process are highly related to weld formation process, which affects the weld quality further. To investigate the influence of the oscillation amplitude on the morphology evolution processes of the keyhole and molten pool during the oscillating laser stake welding of dissimilar materials T-joints, a three-dimensional multiphase flow numerical model is developed. The circular shaped oscillating laser stake welding processes of dissimilar materials T-joints under different oscillation amplitudes are calculated and analyzed in detail. The results show that the depth of the keyhole decreases and the widths of the molten pool and weld at the interface increase with the increase in the oscillation amplitude during the circular shaped oscillating laser stake welding of dissimilar materials T-joints. The periodical expansion and contraction of the keyhole are formed during the welding process. The collapse of the keyhole may cause bubbles in the molten pool due to the instability of the keyhole, and these bubbles also can be captured by the keyhole later.