ANALYSIS OF MECHANICAL AND MICROSTRUCTURAL PROPERTIES OF PULSED CURRENT GAS TUNGSTEN ARC WELDED DUPLEX STAINLESS STEEL

Studies The Demand is increasing for Stainless Steel alloys, due to high strength, good welding properties, increased wear and corrosion resistance and high strength-to-weight ratio. Duplex Stainless Steel is widely used in aerospace applications; Ship building, Automobile Industry, Rail Cars and Pressure Vessels. Pulse Current Welding process has many advantages over Constant Current Welding, including enhanced arc stability, increased weld depth/width ratio, narrower HAZ range, reduced hot cracking sensitivity, refined grain size, reduced porosity, low heat input, lower distortion of gas by weld pool and better control of the fusion zone. Pulsed current welding technology has been widely used in fabrication of high pressure air bottles, high pressure gas storage tanks, rocket motors, structures in aerospace applications such as aircrafts, rockets and missiles. Switching between predetermined high and low level of welding current can be used to produce pulsed current gas tungsten arc welds. Some progress is done on pulsed current GTAW of Duplex Stainless Steel. So far the pulsed current welding is used to study the effect of pulse current, shielding gas composition, weld speed and bead shape, the incidence of welding defects, joint strength, Duplex Stainless Steel, to study the microstructure and weld bead geometry flows.