Effect of auxiliary gas process on double-wire deposition morphology

Double-wire arc additive manufacturing could manufacture large-sized components at low cost and high efficiency; however, serious heat input and heat accumulation result in poor forming quality and limit further efficiency and application. An auxiliary gas process platform for double-wire additive manufacturing is introduced in this paper to explore the influence mechanism of the auxiliary gas on deposition during the manufacturing process. Monolayer and multilayer test results showed that the auxiliary gas had a stirring effect on a liquid molten pool and a cooling effect on deposition layers, and different auxiliary gas parameters could also influence the welding arc stability, which all acted on the deposition morphology. The angle between the auxiliary gas nozzle and welding torch had the greatest impact on the formation of components, followed by the auxiliary gas flow, and the auxiliary nozzle height had minimal influence. When the angle increased from 0° to 30°, the forming morphology gradually flowed. Furthermore, increasing the auxiliary gas flow rate led to the decreased sample height and a serious flowing defect. However, decreasing the nozzle height increased the gas pressure, which would also reduce the height.