Optimization of the Pulsed Gas Tungsten Arc Welding in Dissimilar Joining Austenitic Stainless Steel AISI 316L to Nickel-Base Super Alloy of Monel 400

In this research, optimization of the pulsed gas tungsten arc welding including pulse current, background current, pulse frequency and on time were investigated in welding of non-similar materials of austenitic stainless steel AISI 316L and nickel-base super alloy of Monel 400 by using ERNiCr3 filler metal. In order to obtain optimum conditions of welding the Taguchi method with the L9 array was used. The mechanical properties such as bending, tesile test and hardness test were performed on the samples and after that analysis of the variance was performed. By predicting optimal conditions, the proposed model was examined and the results of computational analysis shows a significant similarity with results of the experiment. Optimal parameters of pulsed tungsten arc welding were the pulse current of 140 mA, background current of 60 mA, pulse frequency of 3 Hz and the ON periods of pulse was 50%. The optimized sample with the Taguchi method and the welded sample shows the similarity of 98.7%. Pulse current percentage of 23.4 and pulse frequency of 28.2 were identified as the most influential parameters during the welding. Tensile test results showed that the failure occurs on the side of the base metal on Monel 400 one and hence the failure is the ductile one. These results show the strength of the weld metal confirmed the tensile and bending tests.