Abstract
The estimation of the electric current distribution on the molten pool was tride by measurement of the electric potential distribution on the back of a thin plate (3.5 mm, Ti-6Al-4V), which is one of the base metals in which it is expected that the anode distributes over the wide range on the molten pool. Electric resistivity of this plate is nearly constant with change in temperature.
The measurement was carried out in a stationary TIG arc with current of 150A and arc length of 3 mm, and in the stationary state of the heat flow (molten pool diameter: 9.5 mm) which is obtained by water-cooling of the back of the plate.
The result was not a Gaussian and an equi-current distribution but an equi-current density distribution (OD:8 mm) or the current distribution for equipotential surface (OD:7 mm) in which the current value at the outside was higher than at the center.
