Effect of Electric Field on Interaction Between Laser and Arc Plasma in Laser–Arc Hybrid Welding

In this paper, the interaction between laser and arc plasma is investigated on the viewpoint of the effect of an electric field. An additional electric field (AEF) is brought into the laser-arc welding system to discover the interaction between laser and arc plasma. Results indicate that the AEF hardly influences the single-arc-welding process; the AEF can increase the laser welding penetrability by speeding the charged particles in keyhole plasma; in the laser-arc hybrid welding, whether the AEF affects the welding process depends on the welding parameters. Based on the experimental results and physical theories, it is confirmed that, when the laser-induced plasma becomes part of arc plasma, the effect of AEF disappears. Therefore, it is deduced that, in laser-arc hybrid welding with proper parameters, the electric field of the arc plasma can influence the laser-induced plasma as the AEF. It is possible for the free electrons to gain some extra energy from the original electric field of the arc plasma, which is beneficial for increasing the welding penetration depth.