EXPERIMENTAL INVESTIGATION OF MICROSTRUCTURE AND MECHANICAL PROPERTIES OF ND: YAG LASER WELDED NICKEL-CHROMIUM BASED ALLOY (INCONEL 625)

Abstract

The influence of various welding parameters on microstructure and the mechanical properties of laser welded Nickel based super alloy Inconel 625 sheets of thickness 1.5 mm were investigated. The various welding parameters used are welding speed (mm/min), pulse width (mm) and laser power (watt). The experimental results for this super alloy showed that the growth of grain structure in the weld zone has been increased significantly. The microstructure of the various samples at fusion zone and heat affected zone (HAZ) was characterized by the optical microscope and field effect scanning electron microscope (FESEM). In comparison with base metal the mechanical properties, i.e. tensile strength of the material has been 90% of its original strength and the micro-hardness of the fusion zone has the maximum value and then at the heat affected zone. The Nd: YAG pulsed laser has been used because of its overlapping factor during welding that reduces porosity in the weld zone.