The effect of external longitudinal magnetic field on laser-MIG hybrid welding

Abstract

Applying the external longitudinal magnetic field to laser-metal inert gas (MIG) hybrid welding, its influence on the arc/plasma shape, motion characterization, and coupling of these two sources are researched using a high-speed camera. It is revealed that the essential effect of the external longitudinal magnetic field on laser-MIG hybrid welding arc/plasma is to make the arc and the coupling process more stable. Through analyzing the position of arc and laser-induced plasma and the mechanical model of charged particles, the energy coupling mechanics of arc and plasma under this welding condition has been proposed. The results showed that an application of a magnetic field can change the arc shape from pyramidal and static to spiral and rotational with high-speed stage and make the arc root diameter increase. It has also been found that the external longitudinal magnetic field can obviously enhance the stability of the process during laser-arc hybrid welding under the best magnetic induction intensity, which promoted efficient coupling and formed a good weld.