Impact of Cold Metal Transfer and Pulse Multicontrol Heat Inputs on SS316L Wire Arc Additively Manufactured Built-Up Properties and Performance

Abstract

Abstract. Wire arc additive manufacturing (WAAM), leveraging traditional gas metal arc welding (GMAW) technology, offers a promising approach for fabricating large-scale metallic components with high deposition rates. Among GMAW-based processes, cold metal transfer (CMT) and pulsed metal inert gas (MIG) techniques differ significantly in their metal transfer mechanisms and thermal inputs, which directly influence the resulting material properties. This study systematically compares the microstructural, mechanical, tribological, and corrosion characteristics of 316L stainless steel walls produced using CMT and pulsed MIG WAAM processes under similar heat input conditions (CMT: 323.48 J/mm, pulsed MIG: 329.14 J/mm). The CMT process produced finer grains (11.16 µm) compared to pulsed MIG (14.14 µm), contributing to slightly higher microhardness (171.90 HV versus 171.14 HV) and improved mechanical properties. Charpy impact toughness, yield strength, and ultimate tensile strength were all higher for the CMT process by 16.4%, 3.4%, and 1.3%, respectively, while pulsed MIG showed slightly higher elongation (56% versus 52.25%). Fractographic analysis revealed finer, more uniform dimples in the CMT samples, indicating ductile fracture behavior. In terms of tribological performance, the CMT process exhibited a lower coefficient of friction (0.216 versus 0.249) and a significantly reduced wear-rate (3.4 × 10−3 mm3/m versus 5.5 × 10−3 mm3/m). Corrosion resistance was also marginally better in the CMT samples, with a corrosion rate of 0.05235 mm/year compared to 0.05524 mm/year for pulsed MIG. Overall, the CMT process consistently outperformed pulsed MIG across multiple performance metrics, making it a more favorable choice for high-integrity additive manufacturing of stainless steel components.