Effect of Laser on Double-Arc Physical Characteristics in Pulsed Laser Induced Double-TIG Welding

In order to improve the energy utilization efficiency of double-TIG arc, based on the synchronous induction of pulsed laser to double-arc, the coupling-enhanced discharge phenomenon between double-arc is studied in this paper. The energy utilization efficiency of pulsed laser induced double-arc is quantitatively analyzed. The physical characteristics of coupling double-arc are studied based on high-speed camera and spectral diagnosis technology. The physical model is established to discuss the particle migration during the coupling discharge, characterizing the movement state of electrons. The results show that Dla (horizontal distance between the tungsten electrode tip and laser beam axis) has a significant effect on the energy utilization efficiency of the heat source. With the increase of Dla, there are three interaction relationships between the double-arc plasma and keyhole plasma: Mutual interference, Coupling-enhanced discharge and No interaction. A suitable Dla can realize the synchronous induction of laser to double-arc plasma, forming a coupling double-arc, the heat source has a higher energy utilization efficiency. The migration of particles in double-arc can be divided into four stages: Double-arc free discharge stage, Laser-induced initial stage, Laser-induced contraction stage and Laser-induced stable stage. Under the induction of laser, the double-arc forms a common compressed conductive channel. The energy density of coupling double-arc reaches 9.3 times that of traditional double-arc, and the total electron kinetic energy increases by 38% compared with traditional double-arc.