Abstract
In order to clarify the physical relation among a tungsten electrode, an arc, a heat transfer to anode and a penetration of a base material in TIG welding process, the electron temperatures of the arc plasma, the distributions of current density and heat intensity on the anode surface, and the cross-sectional areas of the weld penetration of a stainless steel are respectively measured at a 100 A in argon TIG arcs with different conditions of arc lengths and conical tip angles of tungsten electrode. The temperature measurements of electron in the arc plasma by using a laser scattering method show the same temperature close to the tungsten electrode independently of the arc length. But, the electron temperature close to the anode decreases with increase of the arc length. The maximum values of current density and heat intensity on the anode surface also decrease with increase of the arc length. These experimental results are discussed with relation to the cross-sectional areas of the weld penetration. As a result, it is concluded that the electron temperature close to the anode and current density on the anode surface decide the heat intensity distribution on the anode surface and then the heat intensity remarkably dominates the size of the weld penetration in TIG welding process. Furthermore, different conical tip angle of tungsten electrode affects the electron temperature and also the cross-sectional areas of the weld penetration.
