Modeling of Temperature Distribution with Metal Vapor in Pulsed TIG Including Influence of Gas Flow Velocity Affected by Radiation Absorption

Abstract

Pulsed tungsten inert gas (TIG) welding is used to improve the stability and speed of arc welding, and to provide greater control over the heat input to the weld. The temperature and the radiation power density of the pulsed arc vary as a function of time, as does the distribution of metal vapor. They also affect the arc. A self-consistent two-dimensional model of the arc and electrodes is used to calculate the arc properties as a function of time. Self-absorption of radiation is treated in three directions considering absorption throughout the plasma. The relation between the metal vapor and the radiation power density is analyzed by calculating the gas flow velocity affected by the radiation absorption with the iron vapor distribution. The temperature, iron vapor, and radiation power density distributions depend on the self-absorption model that is used. The temperature distribution becomes broader when self-absorption of radiation from all directions is considered. Results show that the temperature distribution is affected strongly by the fast gas flow velocity during the peak current period. During the base current period, it expands to the radial direction.