Analysis of additional electromagnetic force for mitigating the humping bead in high-speed gas metal arc welding

To mitigate the occurrence of humping bead in high-speed gas metal arc welding, an external magnetic field is exerted into the weld pool to produce the forward electromagnetic force and to brake the backward flow molten jet. A thermal-magnetic coupling model is developed to analyze the distribution of the additional electromagnetic force in weld pool. The interaction of the external magnetic field in the arc region with the arc/liquid metal stream at the wire tip is taken into consideration, and the excitation current and the wire-magnet distance are optimized. The welding experiments on mild steel plates (Q235B) demonstrate that with help of the forward additional electromagnetic force, good weld bead quality without humping is obtained in high-speed gas metal arc welding.