Numerical Modeling of Nitrogen Absorption during Gas Tungsten Arc Welding

Abstract

It is problem that nitrogen absorption in gas tungsten arc (GTA) weld metal. Recently, various arc welding simulation techniques have been developed. However, there are few models dealing with the absorption and a mixture of a shielding gas, an atmosphere and a metal vapor.. In this study, intruding behaviors of the atmospheric gas (N₂) into the molten poor and nitrogen transportation phenomenon in the molten poor during GTA welding was investigated using a unified numerical model. This model includes the tungsten cathode, arc plasma and base metal. We take atmosphere (N₂), shielding gas from the gas nozzle and metal vapor from the molten poor into consideration. As a result, we show nitrogen concentration distribution and nitrogen transportation in the molten poor. Additionally, we clarify that these behaviors are affected by the arc plasma characteristics.