Study Of Parametric Effects On Mechanical Properties Of Stainless Steel (AISI 304) And Medium Carbon Steel (45C8) Welded Joint Using GMAW

Abstract Gas Metal Arc Welding (GMAW) is widely used for welding of carbon steel, silicon steel, low alloy steel, stainless steel, Al, Mg, Cu, Ni, Ti and their alloys. Welded surfaces produced are smooth, neat, clean and spatter free which require no further cleaning so reduces total welding cost. Because of the numerous applications of dissimilar metal welded joints, engineers and researchers are opting for dissimilar metal welding to create new structures or parts. Welding of dissimilar metals has more challenging task because the weld ability of dissimilar metals depends on many factors. It is difficult to join two different metals having different chemical, physical and metallurgical properties. A dissimilar metal weld zone contains a weld deposit with a chemical composition that differs by several percent from the composition of the two base metals that have been welded together. In the present study the aim is to weld stainless steel AISI 304 and medium carbon steel 45C8 using GMAW. Yield strength, ultimate tensile strength, weld zone hardness, weld bead thickness and reinforcement of the welded joint have been reported. The variables used are welding current, voltage, speed and gas flow rate. Taguchi’s Method has been employed for design of experiment. Based on ANOVA and S/N ratio analysis, the process parameter which significantly affects the responses is welding current. In the welded zone, the hardness decreases with increasing welding current. It has been observed that with the increase of welding current, weld bead thickness increases and reinforcement decreases. Microstructures of the base metals, both HAZs and weld zone have been investigated. Grain structure changes from base metal to HAZ and HAZ to welded zone. Grain size becomes more compact in welded zone.