Numerical simulation of metal transfer in argon gas-shielded GMAW

Abstract

The gas metal arc welding (GMAW) process combines aspects of arc plasma, droplet transfer, and weld pool phenomena. In the GMAW process, an electrode wire is melted by heat from an arc plasma, and molten metal at the wire tip is deformed by various driving forces such as electromagnetic force, surface tension, and arc pressure. Subsequently, the molten droplet detaches from the tip of the wire and is transferred to the base metal. The arc plasma shape changes together with the metal transfer behavior, so the interaction between the arc plasma and the metal droplet changes from moment to moment. In this paper, we describe a unified arc model for GMAW, including metal transfer. In the model, we do not account for heat transfer in the metal, but the wire melting rate is determined by the arc current. The developed model can show transition from globular transfer at low currents to spray transfer at higher currents. It was found that electromagnetic force is the most important factor at high currents, but surface tension is more important than electromagnetic force at low currents in determining the transfer mode.