Ultrasonic wave assisted GMAW: A novel method adds ultrasonic wave to provide an additional force to detach the droplet

A novel modification to conventional gas metal arc welding (GMAW) was developed by applying ultrasonic wave to the welding process, referred to as U-GMAW. One of the effects was ultrasonic radiation force. The principle of the proposed method is to apply the ultrasonic radiation force to droplets as an extra detaching force. To prove the feasibility of this idea, comparative experiments were conducted to uncover the basic characteristics of the metal transfer process. It was found that droplets in conventional GMAW were approximately spherical, while deformation of the droplets was observed in U-GMAW. More specifically, the droplet was elongated and its size was reduced. As a result, the metal transfer frequency increased in all experimental conditions. Analytical results show that an additional force was brought into the metal transfer process. The additional force was ultrasonic radiation force and its value was on the order of 10^-3 N.