Influence of wire feed speed and torch speed on the mechanical properties of wire arc additively manufactured stainless steel

Wire Arc Additive Manufacturing (WAAM) enables 3D printing of large high-value metal components. However, integrating WAAM into production lines requires a critical understanding of the influence of process parameters on the resulting material characteristics. As such, this research investigates the relationship between WAAM wire feed speed (WFS) and torch speed (TS) on the resulting mechanical characteristics of 316LSi thick parts (2.5 cm - 0.98 in). The experimental procedure is informed by a training matrix that allows parametric analysis of WFS and TS on the ultimate tensile strength (σult), yield strength (σy), elastic modulus (E), failure strain (εf), hardness (HV0.5) and dimensional accuracy (Da) of the printed samples. The research found that WAAM-processed 316LSi parts feature isotropic material properties despite variations in WFS and TS. The developed surrogate model offers five significant polynomial models capable of accurately predicting the influence of WAAM process parameters on σult, σy, εf, E and Da. The research found TS to be the most significant WAAM process parameter in comparison to WFS for σult and εy. On the contrary σy, E and Da were found to be primarily driven by WFS as opposed to TS. Overall, the paper for the first time presents an accurate surrogate model to predict the mechanical characteristics of WAAM 316LSi thick parts informed by wire feed speed and torch speed. The study demonstrates that the mechanical properties of WAAM-processed steel are primarily influenced by the underlying process parameters offering significant potential for tunable performance.