OPTIMIZING WELD QUALITY IN DISSIMILAR STAINLESS STEEL JOINTS FOR INDUSTRIAL APPLICATIONS

The research aims to develop quality joints using cold metal transfer (CMT) welding. We investigated stainless steel sheets such as Duplex 2205, SS 301 LN and ER 308L SS filler wire used for chemical and food processing equipment applications. The major focus was on optimizing the welding parameters for producing quality weld joints, thus ensuring the optimal ultimate tensile strength (UTS) and microhardness (HV0.5). The Taguchi L9 orthogonal array was used in this study to find the most significant parameters among welding speed (S), current (A) and contact-to-work distance (CTWD), and their optimum settings for producing high-quality welds. The multi-objective optimization TOPSIS method was employed to optimize the ultimate tensile strength (UTS) and microhardness (HV0.5). According to the TOPSIS performance index, the welding current was identified as the most influential factor, contributing 94.79 %, followed by welding speed and CTWD contributing 4.48 % and 0.15 %, respectively. The optimized welding parameters including a current of 95 A, welding speed (travel speed) of 4 mm/sec, and CTWD of 5 mm were identified as the best results. Confirmatory experiments were conducted to validate the optimized settings; they demonstrated good agreement with the predicted results. Finally, optical microscopy (OM), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDXS) analyses of the optimal weld microstructure were presented.