Mechanical properties and microstructural characteristics of wire arc additive manufactured 308 L stainless steel cylindrical components made by gas metal arc and cold metal transfer arc welding processes

Abstract

Wire arc additive manufacturing (WAAM) is suitable for manufacturing large-scale complex parts due to many advantages, including high disposition rate and low cost and thus become a viable advanced manufacturing technique. In the present study, two different arc welding processes were used to fabricate 308 L austenitic stainless steel (SS) cylindrical components. The mechanism and impact of the processes on the microstructure and mechanical characteristics were analysed. The results indicated that the component produced by the cold metal transfer (CMT) arc welding process exhibits finer grains and higher amount of ferrite than conventional gas metal arc welding (GMAW) process. Furthermore, the percentage of anisotropy in tensile strength was reduced from 8.07% to 6.21% for cylinders built by the GMAW process to the CMT process. In addition, the average ultimate tensile strength (UTS), elongation (EL) and hardness of the CMT cylinder are 5.17–7.0%, 4.029–7.80% and 4.02–5.88% higher than the GMAW cylinder, irrespective of orientations. The tensile properties are higher than those of the 308 L welding wire and other arc-welding based additively manufactured 308 L stainless steel parts. The produced WAAM 308 L SS cylinders exhibited superior performance than the stainless steel made by industrial forging standards. Therefore, the 308 L SS cylindrical components made by WAAM technique are found to be suitable for industrial application.