Effect of Pulse Currents on Weld Geometry and Angular Distortion in Pulsed GTAW of 304 Stainless Steel Butt Joint

Abstract

In this research, the effect of pulse currents on the weld geometry and angular distortion in pulsed GTAW (PGTAW) process in 3 mm thick SS-304 autogenous butt weld joint was investigated. Welding method uses pulse current and continuous current. The mean current and welding speed were kept constant with the peak current and base current were varied. During pulsed GTAW process, the arc condition was captured directly using a charge-coupled device (CCD) camera. Weld geometry was carried out using a digital microscope. Distortion was measured using Coordinate Measuring Machine (CMM).  The results show that the peak current and base current have an influence on weld geometry and angular distortion. The weld geometry on pulsed GTAW was produced wider of weld bead width than continuous GTAW. However, angular distortion on continuous GTAW was higher than pulsed GTAW.  Pulsed GTAW can widen the weld bead by 0.57% - 25.09%, but can reduce distortion by 15.15%-88.17%. As compared with weld geometry to the continuous GTAW, the widest result occurs at peak current 212A and base current 40A. The smallest of distortion on pulsed GTAW was achieved at peak current 138A and base current 80A.