Effect of wire arc additive manufacturing parameters on geometric, hardness, and microstructure of 316LSi stainless steel preforms

Additive manufacturing (AM) is a manufacturing process based on the creation of a component layer by layer, with the wire arc additive manufacturing (WAAM) technique establishing itself as promising alternative for the production of metal parts. Among the austenitic stainless steel alloys, the ER 316LSi alloy is of great interest in the transport, health, and oil and gas industries, due to its good mechanical properties, biocompatibility, and high corrosion resistance. The aim of this work is to evaluate the influence of process parameters on the geometric characteristics, hardness profile, and microstructure of 316LSi austenitic stainless steel metallic preforms obtained by WAAM, using the controlled short circuit (CCC) as the metal transfer technique. For this purpose, seven metallic preforms were manufactured with different parameters, according to a design of experiments (DoE) of type 22 + 3. Metal transfer via CCC resulted in a rapidly solidifying weld pool suitable for manufacturing WAAM preforms. Among the experimental parameters, the combination of a torch travel speed of 300 mm·min−1 with a wire feed speed 4 m·min−1 provided better visual appearance, with the absence of internal defects, superior surface finishing, more regular hardness profile and fine grain microstructure.