Optimization of ultimate tensile strength of welded Inconel 625 and duplex 2205

Abstract
The ultimate strength is an important property of any material for the manufacturing of components. This paper utilized the laser beam welding (LBW), due to its smaller dimension, which produces lesser distortion and process velocity is higher. Inconel 625 alloy and duplex 2205 stainless steel is having higher strength and corrosive resistance properties. Due to the above-mentioned properties, it could be used in oil and gas storage containers, marine and geothermal applications. This research work presents an investigation of various input variable effects on the output variable (ultimate tensile strength) in LBW for dissimilar materials namely, Inconel 625 alloy and duplex 2205 stainless steel. The input variables for this research are the power of a laser, welding speed, and focal position. The experimental runs are developed with the help of design of experiment (DOE) and utilized statistical design expert software. The ultimate tensile strength on different runs is measured using a universal tensile testing machine. Then from a response surface methodology and ANOVA, the optimum value of ultimate tensile strength was determined to maximize the weld joint and bead geometry. Finally, the confirmation test was carried out, it reveals the maximum error of 0.912% with the predicted value. In addition, the microstructure of the weld beads was examined using optical microscopy.