Effect of electrode shape on TIG arc behavior

Abstract

Tungsten inert gas (TIG) welding has been extensively utilized for wire arc additive manufacturing (WAAM) applications. The presented work investigates the formed arc characteristics for different electrode geometry to enhance the overall process efficiency. The electrode sharpening angle was varied at 30°, 60°, 90°, and 107°. COMSOL plasma module has been utilized for the computation of temperature field, arc pressure, heat flux, and current density variation in arc column. The simulated model was then used to study the influence of input current from 100A to 200A. It was observed that an increase in electrode sharpen angle increases the arc concentration to a narrow area, whereas the increase in arc input current widens the concentration zone at the anode. An experimental study performed at different currents and recorded high-speed arc imaging also confirms the same. It typically follows the gaussian distribution. However, the magnitude of the temperature field, arc pressure, heat flux, and current density varies in arc columns. The volumetric distribution of these properties was higher near the cathode or electrode for a higher electrode angle and was found to be a good choice for WAAM.