Publication

Abstract : The dissimilar butt welding of nickel 201 and AISI 316 was investigated using 4 kW CO2 laser welding machine. The effects of laser power (2580 3420 W), welding speed (450 1150 mm/min), focal position (-1 to 0 mm), beam angle (84 96 degrees) and Beam offset (0 0.2 mm) on the weld geometry i.e, depth of penetration (DP), bead width (BW) and Fusion Zone Area (FZ)were investigated using Response Surface Methodology (RSM). The central composite design was used for this experimental plan. Mathematical equations were developed to predict the required weld profile responses dissimilar butt welding process. The sequential Ftest, lack of fit test and analysis of variance (ANOVA) technique where used to test the adequacy of the developed models. Output responses reflect the results for the mathematical models within the limits of the input process parameters that were used. Numerical optimization technique was used to identify the optimal condition region of all this laser welding process. Laser welding speed played a major role in this process, which causes pores nearby fusion zone. Depth of penetration is the most important output response to achieve the good dissimilar joint. In microstructure studies some delta ferrite is seen in the interdendritic region and also the solidification shows columnar grains. The tensile test results the fracture in the base metal which proves that the weld strength is good as expected. The optimum conditions are obtained from Desirability analysis. A set of Pareto-optimal solutions provides flexibility to the welding industry and the process engineer to select the best setting based on the quality requirements and applications.