Investigation on the microstructure, tensile, microhardness, and corrosion properties of wire arc additive manufactured SS309L

This study investigates the microstructure, tensile properties, microhardness, and corrosion behavior of SS309L walls fabricated using cold metal transfer (CMT)-based wire arc additive manufacturing (WAAM). The microstructure of the deposited layers was analyzed and compared with previous studies. The findings indicate that the microstructure along the build direction is heterogeneous, consisting of austenite and delta ferrite (δ-ferrite) phases. The austenite phase increases from top to bottom due to cyclic heat transfer. The top region exhibits finer grains and a higher δ-ferrite content due to rapid cooling, resulting in increased microhardness. The average tensile strength of the WAAM-fabricated samples was slightly lower than that of the feed wire, while elongation values were comparable, demonstrating the suitability of WAAM for stainless steel part manufacturing. The fabricated samples exhibited excellent corrosion resistance, with a corrosion rate ranging from 0.01 to 0.023 mm/year. The primary mode of corrosion was identified as pitting corrosion. These findings contribute to the advancement of WAAM technology in industrial applications, particularly for fabricating stainless steel components with enhanced mechanical performance and corrosion resistance. The study provides valuable insights into optimizing WAAM processing parameters to achieve superior structural integrity, making it a viable alternative for manufacturing cost-effective and high-performance stainless-steel parts in the aerospace, marine, and automotive industries.