Effect of process parameters on weldability of austenitic stainless steels: Cryogenic grades of 304, 316, and 201LN—A review

The current study examines the effects of various welding parameters on weld quality, as well as the mechanical and microstructural characteristics of austenitic stainless steel (ASS) 304, 316, and 201LN welds. Gas metal arc welding (GMAW), gas tungsten arc welding (GTAW), and Cold metal transfer (CMT) welding processes were used for investigation. Arc voltage, welding current, welding speed, wire feed rate, gas flow rate, and geometry of the weld bead were selected for investigation. Various optimization techniques like the RSM approach, grey-integrated Taguchi, and genetic algorithms were used to study the effect of process parameters. It was observed that the medium value of the arc voltage (18.5 V) significantly affected the micro-hardness, with the maximum hardness of 268.86 VH in all welded joints with a wire feed rate of 116 mm/s and WD of 0.8 mm, while the wire feed rate (137 mm/s) had the biggest impact on the tensile strength (662.8 MPa) of the joints with an arc voltage of 19 V and WD of 1 mm. The material’s tensile and bending strengths are influenced by current, speed, and root gap. The HAZ of every joint exhibited evidence of grain coarsening. The best quality weld was found at a low level of heat input (1.25 kJ/mm) with maximum UTS and toughness. It has also been observed that grain coarsening occurs as heat input rises. The effect of gas flow rate on weld quality was also assessed.