Analysis of behavior of plasma temperature field and concentration field of metal vapor in TIG welding

In arc welding, heat source property of arc plasma depends on temperature of arc plasma. Temperature distribution of arc plasma is affected by metal vapor which evaporate from molten metal. In this paper, dynamical temperature distribution during TIG welding is obtained through optical measurement with a high speed video camera. Furthermore, spectral images of metal vapor are taken simultaneously, therefore distributions of metal vapor are also obtained. Temperature of arc plasma decreases with mixing metal vapor into the arc plasma. Manganese vapor, namely the metal which has low boiling point, is distributed widely, and concentration is high. On the other hand, iron vapor, namely the metal which has high boiling point, is distributed only near the center of the arc, and concentration is low.