Effect of Anode Heat Transfer on Melted Penetration in Welding Process by Free-burning Argon Arc

Abstract

In order to make clear the physical relation among the arc plasma, the anode heat transfer and the results of materials processing by thermal plasma, namely, free-burning arc, the materials processing was focused on the welding for simplification of discussion. The experimental results of temperature measurements of arc plasma, the distributions of current density and heat input density on the anode, and the weld penetration were presented. It was shown that the electron temperature above the anode and current and heat input density on the anode was dominated by the position of the tungsten cathode. Furthermore, it was also shown that electron temperature of arc plasma was dominated by the cathode shape. These results were related with the results of the welded penetration. As a result, it was concluded that the electron temperature above the anode and current density distribution on the anode decided the heat input density distribution on the anode and then the heat input density on the anode remarkably dominated the size of the weld penetration in the welding process by the free-burning argon arc. Furthermore, it was suggested that the cathode played the important role in the determination of the weld penetration.