Effect of Welding Speed on the Droplet Transfer in High-Power Laser-MAG Hybrid Welding of 12-mm-Thickness Steel Plates for Shipbuilding
摘要
High-power laser-arc hybrid welding is a key technology for thick plate applications such as shipbuilding, where process stability is intrinsically linked to droplet transfer behavior. However, the influence of welding speed on droplet transfer remains a topic of debate. This study systematically investigates the effect of welding speeds ranging from 1.5 to 2.1 m min−1 on droplet transfer stability. We reveal that increasing the welding speed has a detrimental effect on droplet transfer. The underlying mechanism is that as speed increases, the laser’s guiding effect on the arc weakens. This diminishes the stabilizing electromagnetic and plasma drag forces while intensifying the impeding metal vapor recoil force. This force imbalance leads to a decrease in droplet transfer frequency. At the high speed of 2.1 m min−1, process stability significantly deteriorates, manifesting as an increase in unstable short-circuit transfers accompanied by severe spatter. This work clarifies the physical mechanism by which excessive welding speeds destabilize droplet transfer, providing a theoretical basis for process optimization and quality control in high-speed, high-power thick plate welding.