Study of Metallurgical and Mechanical Behavior of Laser Butt-Welded Dissimilar Joint of Inconel and Stainless Steel
Abstract High energy density welding processes like laser and electron beam welding are capable of welding dissimilar plates with much ease due to high power density and low heat input in spite of the varying thermos-physical properties of the used alloys. The present work is aimed to check the feasibility of joint prepared with laser welding of SS 316L and Inconel 718 plates. The experiments are designed to study the effect of welding speed on the mechanical and metallurgical behavior of the joints without any offset to joint line. The formation of laves phases is confirmed by energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) phase analysis. These laves phase are micro-segregation of Nb, Fe, C and Cr, which is because of high temperature in a small area of fusion zone (FZ) due to intense heat of laser source. Micro-segregation of different elements has led to micro-fissures, which is detrimental for the joints operating at elevated temperature. Cooling rate and peak temperature during welding play the significant role in obtaining a sound quality joint. The present work gives an insight on feasibility of laser welded joint of SS 316L and Inconel 718 with suitable selection of welding speed during laser welding.