Numerical Simulation of Metal Vapour Behavior in Double Electrodes TIG Welding
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Metal vapour from the weld pool in double electrodes tungsten inert gas welding is taken into account by a unified numerical model including the arc plasma and the weld pool. The thermodynamic properties and transport coefficients of the arc plasma are dependent on both the local temperature and the mass fraction of the metal vapour. A second viscosity approximation is used to describe the diffusion coefficient of the metal vapour in the arc plasma. The temperature and the flow fields of both the arc plasma and the weld pool are calculated together with the metal vapour concentration. The simulated results are presented for the cases of 3 and 9 mm electrode separation, respectively. It is shown that the metal vapour behavior is much different in these two cases. In the case of 3 mm electrode separation, the metal vapour above the mass fraction of 0.2% is concentrated just above the weld pool surface, while in the case of 9 mm electrode separation, the metal vapour is diffused to the most region of the arc plasma for the same range of mass fraction. In addition, the arc plasma temperature as well as the heat flux at the weld pool is constricted by the presence of the metal vapour. The constricted heat flux at the weld pool results in an increase in the temperature of the weld pool about 100 K or less but a slight shrinkage of the weld pool shape.
KeywordsMetal vapour Double electrodes Welding Numerical simulation
The authors are grateful to Dr. A. B. Murphy of CSIRO Materials Science and Engineering for his providing of mixture plasma properties of Ar–Fe. This work is supported by National Science Foundation of China (51705054) and Scientific and Technological Research Program of Chongqing Municipal Education Commission (Grant Nos. KJ1600903 and KJ1709197).
- 3.Li KH, Chen JS, Zhang YM (2007) Double-electrode GMAW process and control. Weld J 86:s678–s689Google Scholar
- 14.Ogino Y, Hirata Y, Kawata J, Nomura K (2013) Numerical analysis of arc plasma and weld pool formation by a tandem TIG arc. Weld World 57:411–423Google Scholar
- 26.Fan D, Huang Z, Huang JK, Wang X, Huang Y (2015) Three-dimensional numerical analysis of interaction between arc and pool by considering the behavior of the metal vapour in tungsten inert gas welding. Acta Phys Sin 64:108102Google Scholar