Optimization of Process Parameters during Multipass Metal Inert Gas (MIG) Welding of SS304 Stainless Steel

Abstract

Stainless steel is very popular in fabrication industry because of its excellent properties like high strength at low temperatures and corrosion resistance. It is used as structural material in nuclear reactors, valve bodies, chemical vessels, dairy industry and for carrying and storage of liquid nitrogen. Welding is important fabrication process used for processing of stainless steel. Quality of a joint is affected by the welding input parameters. In present study the effect of various MIG welding input parameters like voltage, current, gas flow rate, interpass temperature and groove angle were investigated. Effect of input parameters on distortion, impact toughness and microhardness of weld joint is studied. Mode of failure in fractured toughness samples is also investigated. Taguchi L18 orthogonal array was used for designing of experiment and results were analyzed by ANOVA. The responses measured in this study were charpy impact toughness test at room temperature and at -20 ̊ C, Distortion in welds, microhardness at fusion zone and heat affected zone, microstructural study and SEM of fractured samples of impact testing. Microstructural study was done by optical micrographs. SEM images of fractured samples were used to find the mode of fracture.