Optimization HW-GTAW process parameters in the joining of austenitic stainless steel with historic data design and zebra algorithm

This research article presents the optimization of the hot wire gas-tungsten arc welding (HW-GTAW) process parameters for joining AISI super 304 H (SS304H) plates with experiments designed using historic data design methodology. HW-GTAW can overcome the low deposition efficiency of the conventional GTAW process. The current of hot wire, welding current, and wire feed rate are the input factors, and the weight of weld deposition (WWD) and bead width (BW) are the outputs measured for analysis. Micrographs of weldment show defect-free joints; a higher wire feed rate leads to the disturbance of the main arc, whereas a lower wire feed rate results in droplet transfer, interrupting the welding. The weld interface exhibits the presence of finer grains and partially deformed grains in the partially mixed zone (PMZ) and coarser grains in a heat-affected zone (HAZ). The presence of columnar dendrites leads to superior tensile properties compared to the base metal. Optimization shows that the joint fabricated with a welding current of 150 A, hot wire current of 40 A, and a wire feed rate of 1500 mm/min exhibits a higher WWD and BW of 23.97 g and 13 mm, respectively. Wire feed rate revealed a higher influence on WWD, and welding current has a higher effect on the BW of SS304H joints. The optimized SS304 H joint exhibits a maximum strength in tension (598 MPa) and a mean hardness of 188 HV at the fusion zone (FZ) and HAZ. Nature-inspired metaheuristic zebra optimization algorithm also produces identical results from desirability analysis of historical data.