Effects of a constricted nozzle on the arc phenomena in the TIG welding process

Abstract

Figure 1 is a schematic of the computation model for TIG welding with a constricted nozzle attached. Since, however, in the actual computation model, the arc length is very much smaller than the horizontal dimension of the domain, Figure 1 is drawn so that the domain is readily comprehensible and is not to scale. The computational model, which assumed axial symmetry of the two-dimensional cylindrical coordinate system, comprised the tungsten electrode, gas nozzle, constricted nozzle and base metal. The dimensions of the domain are 37 mm in the axial direction and 25 mm in the radial direction. The diameter of the tungsten electrode was 1.6 mm and the electrode tip angle was 30°. The diameters of the (standard) gas nozzle and constricted nozzle were, respectively, 12.1 and 3.0 mm and the nozzle tip positions were, respectively, 4.0 and 2.5 mm from the base metal surface. The base metal is SUS304 and the arc length was 1.0 mm. The shield gas was argon and this was supplied between the tungsten electrode and constricted nozzle and between the constricted nozzle and the gas nozzle, at the top boundary of the computational domain, at rates of, respectively, 3 and 7 L/min, a total of 10 L/min. The same velocity distribution as in Sansonnens et al.[2] was used. The welding current was DC 80 A and this was introduced from the top boundary of the tungsten electrode.The boundary conditions were that the temperature of the outer edges (top edge, right edge and bottom edge) of the computational domain, excluding the tungsten electrode, nozzles and base metal,

Research and Development of a Novel TIG Welding Torch for Joining Thin Sheets

“…In a paper by Konishi et al, the influence of the constricted nozzle was discussed using numerical simulation in the case of 3 mm arc length [13] with an anode of water-cooled copper. The results showed that, in comparison to the conventional TIG welding process, the heat flux on the anode surface was increased.…”