Mechanical, microstructural evaluation and optimisation of laser welded AISI 316l and incoloy 825 (UNS SO8825) alloy

Abstract

This work articulated a study of dissimilar weld on AISI 316L austenitic stainless steel and Incoloy 825 Ni-based alloy using laser welding on its mechanical and microstructural characteristics. Welding was accomplished by Nd:YAG pulsed laser beam welding process. The laser beam welding has certain advantages over other welding techniques due to its less heat affected zone, high power intensity, high repetition rate. This work investigates the process parameters like laser focal diameter, power and pulse frequency in Laser welding for the above dismillar metal plates. Characterization was conducted by optical microscopy, to understand the microstructural changes occured during the welding process. The tensile test, Vickers micro-hardness tests and the properties of weld joints were investigated using Universal testing machine, Vickers micro hardness tester and the optical microscope. The process parameters were fixed based on the design suggested by Taguchi method. Based on the test results after welding, the values were fed into the MINITAB software for optimization. From the ANOVA, the most influencing parameter which affects the mechanical properties were found and the best combination and level of process parameter was found using optimization.