Magnetic forces acting on molten drops in gas metal arc welding

In gas metal arc welding, magnetic forces arising from the interaction of the welding current with its own magnetic field play an important role in the detachment of drops from the molten welding electrode. These forces drive the dynamic evolution of the drop and also depend on the instantaneous shape of the drop. In this paper, experimentally observed manifestations of magnetic forces are shown and a technique for approximating the temporal evolution of the axial magnetic force from experimentally measured drop shapes is reported. The technique provides quantitative data illustrating the large increase in the magnetic forces when a drop detaches from the electrode.