Effect of Welding Processes on Microstructure, Mechanical Properties, and Corrosion Behavior of Low-Nickel Austenitic Stainless Steels

Abstract

In the present study, the influence of welding process on metallurgical, mechanical, and corrosion behavior of shielded metal arc welding and tungsten inert gas welding was explored using 308L electrode. Tungsten inert gas welding exhibited equiaxed grains, having better hardness and tensile strength than that of its counterpart. It is observed that heat-affected zone and unmixed zone of shielded metal arc welding is wider than tungsten inert gas welding. Dendrite length and inter-dendritic distance are smaller for tungsten inert gas welding. The volume fraction of ferrite is found to be higher in tungsten inert gas welding. The base metal shows higher ductility than both the weld; also, the ductility of tungsten inert gas welding was marginally better than shielded metal arc welding. Modified Strauss test shows intense grain dropping and strength reduction in both the process. The pitting corrosion resistance is found to be better for tungsten inert gas welding as compared to shielded metal arc welding. The galvanic current shows higher current density when couples are formed with base metal and weld zone produced by tungsten inert gas welding.