Effects of arc current and travel speed on the processing of stainless steel via wire arc additive manufacturing (WAAM) process

Wire Arc Additive Manufacturing (WAAM) is an additive manufacturing process that uses an electric arc as the heat source to melt the feed metal wire and deposit it as per the desired 3D shapes. The current study investigates the influence of critical process parameters, namely welding current and travel speed, on the bead geometry and microstructure of deposits of stainless steel (308L). The results reveal that higher welding currents lead to increased bead width, while travel speed inversely affects bead height. Moreover, contact angles between the deposited material and the substrate increase with the welding current. An analysis of the liquid-to-vapor transition (δ) highlights its correlation with travel speed, impacting the spreadability of the deposited material. Notably, among all tested combinations of current and travel speed, 120 A and 25 mm/min yield uniform layer deposition of 308L stainless steel wire, an ideal outcome for WAAM applications. Additionally, it was observed that the percentage of the ferrite phase within the deposited material’s microstructure exhibits an intriguing relationship, increasing with travel speed while decreasing with rising current and layer number. These findings offer valuable insights into process optimization for WAAM-based orthopedic applications, emphasizing the potential for customized orthopedic knee implants with improved quality and performance.