The effect of a hot-wire in the tandem GMAW process ascertained by developing a multiphysics simulation model

Physical phenomena such as arc interference, deflection in droplet transfer, and bulging in weld pool are observed in the tandem gas metal arc welding (GMAW) process. A hot-wire with opposite polarities to the leading and trailing electrodes was introduced to counter these phenomena. The effects of the hot-wire were assessed experimentally. A 3D steady-state numerical analysis model was used to calculate the temperatures and the shapes of the leading and trailing arcs, respectively, as well as the arc flows and the electromagnetic forces. The results of our experiments and our numerical analyses clarify the effects of a decrease in the electromagnetic force around tandem electrodes due to the hot-wire. This decrease mitigates arc interference and the deflection in droplet transfer. Furthermore, it plays a role in reducing the height of the bulge generated on the surface of the weld pool. These effects can prevent defects in tandem GMAW processes.