Effect of reverse-polarity hot wire on the tandem arc welding process

A novel three-dimensional two-step numerical model was developed and analyzed for a tandem process with a reverse-polarity hot wire. Magneto-hydrodynamic analysis was conducted and the free surface of the molten pool was tracked to investigate the arc and molten pool behaviors of the proposed process, respectively. The results indicated that a change in electromagnetic force by the hot wire reduced arc deflection, which increased the arc velocity in the co-axial direction of electrodes, thereby increasing the arc pressure and arc shear force acting on the molten pool. Consequently, the molten pool in the novel tandem process was wider and deeper than that in the conventional tandem process.