Optimization of process parameters in laser welding of dissimilar materials in lap joint configuration using multi-objective Taguchi analysis

Abstract

The need of joining of dissimilar materials goes on increasing day by day in industry due to its high demand. Dissimilar joints are based on both technical and economical aspects, because they can provide satisfactory service performance and reasonable cost savings. Joints between dissimilar metals are particularly common in components used in the automotive, power generation, chemical, petrochemical, nuclear and electronics industries. Again, laser welding with high power density, high degree of automation and high production rate is extremely advantageous in industrial applications and laser welding is most suitable for dissimilar materials. hence optimization of process parameters is necessary for laser welding of dissimilar materials so as to find good weld quality. In this project two dissimilar materials namely AISI 316L and AISI 1552 were taken for laser welding in lap joint configuration. Three process parameters i.e. scan speed, pulse frequency and pulse diameter at four levels were taken for optimization. Two response parameters namely weld hardness and length of heat affected zone were considered for different combinations of process parameters. Grey Taguchi methodology with L16 orthogonal array was used to optimize specified parameters. It is found that laser welding with scan speed of 45 mm/min, pulse diameter of 0.3 mm and pulse frequency of 7 Hz yields the optimal quality characteristics. In these levels hardness of weld zone was found to be 304.77 HV and length of HAZ to be 0.0852 mm.