Plasma Properties of Helium Gas Tungsten Arc with Metal Vapor

Abstract

Energy source properties of electric arcs strongly depend on physical properties of the arc plasma. In a welding process, it has been experimentally confirmed that an admixture of metal vapor diffused from a high temperature weld pool drastically changes the properties of arc plasma and lowers its temperature. However, the effect of the admixture on heat input characteristics to a base metal is not clear due to the difficulty of the experimental study. In this paper, energy source properties of He GTA with the admixture of metal vapor were numerically analyzed. Consequently, it was found that the intense radiation generated by the dense metal vapor constricts the current density distribution especially near the arc axis and decreases the heat input to the base metal.