IMPROVEMENT IN DROPLET TRANSFER PROCESS OF GAS METAL ARC WELDING BY WIRE OSCILLATION

摘要

Gas metal arc welding has been generally accepted as the preferred joining technique for high production and automated welding applications. A separate control of arc energy and arc force is an essential way to improve the welding quality and get the projected metal transfer mode. One of the most effective methods for obtaining separate control is to exert an additional force on the metal-transfer process. In this paper, the droplet-transfer process with an additional mechanical force is studied. The welding system is comprised of an oscillating wire feeder. The images of molten-metal droplets were captured by a high-frame rate digital camera, and both the macro-appearance and the microstructure of the weld beads were analyzed. The results showed that the droplet-transfer mode could be significantly improved by wire-oscillation. The droplet-transfer rate was doubled at a wire oscillation frequency of 85 Hz with respect to the classical welding process, and the droplet size was uniform and stable when increasing the arc voltage. In consequence, a high-quality welding was achieved with uniform, smooth, and pore-free weld beads.