Heat Source Control During Hybrid Laser-Arc Welding (HLAW) of AZ61 Alloy
R-Q. Xu, K. Li and M-H. Chen
Hybrid laser-arc welding (HLAW) offers significant advantages over other techniques when it come to welding Mg alloys. This work shows that the weld quality of Mg alloy plates depends on the control of the laser-arc heat source as interactions between the laser beam and the arc dominate the laser-arc heat source state. Enhancing interactions between the laser beam and the welding arc take place based on mass and energy exchange between laser-induced plasma and the arc. The connection of the two plasmas changes the discharge state of the welding arc and, thus, makes the most efficient use of heat source energy. This leads to significantly improved welding depth of the HLAW heat source. Laser-arc distance is the key factor dominating the interactions between the two plasmas and we demonstrated that with accurate control of the distance, an enhanced hybrid heat source was be obtained.
Keywords: Nd:YAG laser, AZ61, Mg alloy, hybrid laser-arc welding (HLAW), arc behaviour, heat source state