Influence of metal transfer behavior under Ar and CO2 shielding gases on geometry and surface roughness of single and multilayer structures in GMAW-based wire arc additive manufacturing of mild steel

Wire arc additive manufacturing (WAAM) is advantageous for fabricating large-scale metallic components; however, a high geometric accuracy as that of other AM techniques cannot be achieved because the deposition process with large layer. This study focuses on WAAM based gas metal welding (GMAW). To clarify influence shielding used to protect molten during fabrication built part obtained via GMAW-based process, transfer behavior geometry and surface roughness fabricated structures was investigated visualization using high-speed camera when single multilayer depositions were performed under different heat inputs gases. It known Ar not suitable steel it provide desired stability weld bead characteristics. The results reveal stable in short-circuit at input 1.17 kJ/cm enables smoothing irregularities. Better oxygen content 22 wt%. Furthermore, between droplet surface, where pool insufficiently formed, resulted hump formation. indicate proper use can improve quality depositing rough surfaces.