Physical characteristics of triple-wire gas indirect arc plasma

Abstract

The triple-wire gas indirect arc welding (TW-GIA) has advantages of high deposition rate and low heat input. However, due to the lack of accurate understanding of the physical characteristics of arc plasma, the further development of this technology is restricted. In this paper, numerical simulation is used to quantitatively analyze the arc physical characteristics of TW-GIA. The results show that the TW-GIA consists of two separate arcs during the ignition stage, and then gradually couples into a single inverted cone arc. The arc temperature is symmetrical along the main wire. The current density of the stable arc is concentrated at the end of the three wires, and the maximum current density of the main wire end is 2.28–2.92 times that of the side wire. The magnetic field intensity at the symmetrical position along the main wire is in the opposite direction, and the values are basically the same. In the X-axis direction, the energy flow density presents an “M" type characteristic. In the Y-axis direction, as the distance from the main wire increases, the energy flow density first decreases sharply, then slowly increases, and then decreases. The measured arc morphology and electron temperature agree well with the calculated results.