Understanding the changing mechanism of arc characteristics in ultrasound-magnetic field coaxial hybrid gas tungsten arc welding

Ultrasound-magnetic field coaxial hybrid Gas Tungsten Arc Welding (U-M-GTAW) is proposed as a means to control arc characteristics. The arc characteristics and the mechanism to change them, in an ultrasound-magnetic field coaxial hybrid GTAW, were studied by both experimental and theoretical analyses. The results showed that a periodic rotation and compression of the arc shape were obtained in U-M-GTAW and the arc energy was also enhanced. The most obvious compression of the arc shape in U-M-GTAW was obtained, compared with GTAW, M-GTAW and U-GTAW. At the same time, a periodic rotation of the arc was observed in U-M-GTAW. The geometric parameters of the arc shape in U-M-GTAW are reduced more than double compared with traditional GTAW. The arc voltage in the hybrid GTAW was increased, especially in the U-M-GTAW. The electromagnetic force and acoustic radiation force were the main factors for the change of arc characteristics in the U-M-GTAW.