Fast-convert ultrasonic frequency pulse GTAW arc behavior

Based on ultrasonic frequency pulse gas tungsten arc welding(GTAW) power, the out current with di/dt≥50A/μs for the ultrasonic fast current rate of rise and fall was achieved. The arc behavior was investigated in the use of ultrasonic frequency pulse tungsten inert-gas welding for 0Cr18Ni9Ti stainless steel, including the electrical characteristics of arc, the arc force and welds penetration rate. The experimental results show that compared with conventional direct current GTAW, arc plasma has an obvious pinch effect, and the arc force a huge increment with the effect of ultrasonic frequency pulse current. Similarly, the weld penetration of ultrafast frequency pulse GTAW could be improved with enhance of the arc force as the increasing depth of penetration and the decreasing weld width. It is beneficial to improve weld quality and effectively to achieve perfect welds of 0Cr18Ni9Ti stainless steel.