Analysis of weld characteristics of micro-plasma arc welding and tungsten inert gas welding of thin stainless steel (304L) sheet

This research work focuses on comparison of the weld geometry, distortion, microstructure and mechanical properties of thin SS 304 L sheets (0.8 mm thickness) welded using micro-plasma arc welding and tungsten inert gas welding process. Initial experiments were performed to identify suitable processing parameters for micro-plasma arc welding and tungsten inert gas welding processes. Microstructures of welds were analysed using scanning electron microscopy, X-ray diffraction and energy dispersive spectroscopy. The results indicate that the joint produced by micro-plasma arc welding exhibited higher tensile strength, higher ductility, smaller dendrite size and a narrow heat affected zone. Samples welded by micro-plasma arc welding process had lower distortion as compared to that welded by tungsten inert gas process. Micro-plasma arc welding was shown to be the suitable process for welding of thin 304 L sheets owing to its higher welding speed and better weld properties as compared to the tungsten inert gas welding process.