A unified numerical model of MIG welding process

Abstract

Gas metal arc welding (GMAW) is an indispensable technology in various industrial fields as a highly productive process. It uses consumable wire electrodes, and involves metal transfer phenomena. In the metal transfer phenomena, a molten metal detaches from a wire tip to the base metal. Properties of the metal transfer such as droplet size and frequency of transfer is closely related to the stability and quality of overall process. Therefore, appropriate control of the metal transfer is highly desirable. However, there are many transfer modes, and the process is not yet fully understood due to its complexity, so it is difficult to control the metal transfer completely. In this study, in order to make clear about the phenomena of MIG welding process, a unified numerical model is constructed. This model contains both of the arc plasma, metal transfer and weld pool phenomena. In case of arc current is under 230 A, globular transfer is appeared. In case of using higher current, the transfer mode becomes spray transfer. The average temperature of the droplets are depends on the transfer mode. When the transfer mode is globular transfer, the droplet temperature is about 2700 K, and in case of spray transfer, the droplet temperature is about 2900 K.