Measurement of dynamical variation in two-dimensional temperature distribution of TIG pulsed-arcs

TIG pulsed-arc welding is suitable for back-bead welding, thin plate welding and so on, because the heat source properties can be controlled by current waveform. The heat flux onto the base metal is affected mainly by thermal conduction and electron condensation from the arc. Both factors strongly depend on the temperature distribution and current path in the arc. In order to clarify the heat source properties of TIG pulsed-arc, dynamic variation in two-dimensional temperature distribution of TIG pulsed-arc was measured through Fowler-Milne method with a high speed video camera as a first step of the study. As a result, it was found that the arc column was expanded in radial direction and the maximum arc temperature was 20,000K during the peak current of 200A. On the other hand, the width of the arc column decreased especially in the downstream region of the arc and the maximum arc temperature fell to 17,500K during the base current of 50A.