Proceedings of the KWS Conference (대한용접접합학회:학술대회논문집)
- 2002.10a
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- Pages.76-81
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- 2002
A MECHANISM OF DEEP WELD PENETRATION IN GAS TUNGSTEN ARC WELDGING WITH ACTIVATING FLUX
- Manabu Tanaka (Joining and Welding Research Institute, Osaka University) ;
- Hidenori Terasaki (Joining and Welding Research Institute, Osaka University) ;
- Masao Ushio (Joining and Welding Research Institute, Osaka University) ;
- John J. Lowke (CSIRO) ;
- Yang, Chun-Li (Harbin Institute of Technology)
- Published : 2002.10.01
Abstract
The dramatic increase in the depth of a weld bead penetration has been demonstrated by welding a stainless steel in GTA (Gas-Tungsten-Arc) process with activating flux which consists of oxides and halides. However, there is no commonly agreed mechanism fer the effect of flux on the process. In order to make clear the mechanism, each behavior of the arc md the weld pool in GTA process with activating flux is observed in comparison with a conventional GTA process. A constricted anode root is shown in GTA process with the activating flux, whereas a diffuse anode root is shown in the conventional process. These anode roots are related strongly to metal vapor from the weld pool and the metal vapor is also related to temperature distributions on the weld pool surface. Furthermore, it is suggested that a balance between the Marangoni force and the drag force of the cathode jet should dominate the direction of re-circulatory flow in the weld pool. The electromagnetic force encourages the inward re-circulatory flow due to the constricted anode root in the case with flux. The difference in flow direction in the weld pool changes the geometry or depth/width ratio of weld bead penetration.