Microstructure and mechanical performances of stainless steel cladding by twin-electrode GTAW

Abstract

Twin-electrode GTAW is a novel welding technology in recent years and attracts lots of attention to researchers. However, stainless steel cladding with twin-electrode GTAW has been scarcely reported. This paper investigates the microstructure and mechanical performances of austenite stainless steel cladding by twin-electrode GTAW, and particularly the heat input is concerned. Experimental results of hardness tests, bending tests, and corrosion resistance tests show that both single GTAW and twin-electrode GTAW produce defect-free weld beads which meet engineering standards. Compared to single GTAW, twin-electrode GTAW improves the welding productivity at a lower heat input because of its higher welding speed and melting rate. Oscillation twin-electrode GTAW cladding also produces fine weld bead formation, but causes excessive heat input due to its very low welding speed and relative large welding currents. During oscillation twin-electrode GTAW, Fe-Cr-(Mo) intermetallic compound (σ phase) tends to precipitate in the weld bead, which leads to undesirable ferrite content results.