Experimental Investigation on Surface Hardness of Shot Peened Laser Welded Super Austenite Stainless Steel/hastelloy C2000 Dissimilar Joints

Abstract The surface hardness of shot peened processed dissimilar joints of Super austenite stainless steel (SASS) and Hastelloy C2000 was analyzed by the laser beam welding (LBW). The proposed materials have promising role in marine, aerospace, piping and chemical industries. In this research, dissimilar joints of above said two materials were made by LBW after low pressure shot peening (LPSP) performed at the fusion zone (FZ) and the heat affected zone (HAZ). The microstructures and surface morphology were analyzed using Optical Microscopy (OM), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX). Alpha and secondary phases generated at FZ and HAZ are identified in the X-ray diffraction (XRD) results. In FZ and HAZ, the high heat input damaged the α'- austenite phases, where the α phase and S phase were transformed into the α'-martensite phase and notable twin boundaries. Grain boundary growth was found on the outer and mid-surface layers of the weldments by compressive residual stress analysis. No cracks or flaws were found in the crystal structure. The hardness of the weldments was enhanced by the LPSP technique applied in both FZ and HAZ.