TIG double-electrode welding: insights into electrical and geometric parameter effects on process stability and seam quality

Abstract This study investigates the tungsten inert gas double-electrode (TIG-DE) welding process. The motivation for developing the TIG-DE process lies in its potential to significantly enhance productivity and versatility, especially for additive manufacturing applications. The focus is on the interaction between electrical parameters and geometric configurations to analyze the seam outcome. It is observed that increasing current and voltage broaden weld seams, with an elliptical penetration profile that reorients significantly at higher currents. Larger electrode angles, such as 50°, produced wider weld seams, enhancing base material fusion and overall weld robustness. Optimal electrode spacing proved crucial for arc stability and molten pool control. Tight electrode spacing results in lower arc pressures and a slightly elliptical arc shape, significantly lower compared to a single electrode process with the same total current. Larger spacings lead to arc separation and multiple arc pressure maxima. High welding speeds introduce instability, causing the arc to detach from the melt pool, a phenomenon exacerbated by directional dependencies in voltage profiles. The combined effects of torch inclination angle, electrode spacing, and arc length are visualized in welding range diagrams, which depict stable and unstable parameter ranges, arc separation conditions, and scenarios of insufficient energy input. These findings highlight the need for ongoing research and pave the way for developing advanced demonstrators to refine the TIG-DE welding process, particularly for additive manufacturing applications.