Acta Metallurgica Sinica (English Letters)

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Numerical Simulation of the Dynamic Behaviors of a Gas Tungsten Welding Arc for Joining Magnesium Alloy AZ61A

Zhenmin WANG1), Fang YAN2),Pengcheng ZHAO2)   

  1. 1) School of Mechanical & Automotive Engineering, South China University of Technology, Guangzhou 510640, China
    2) College of Electromechanical Engineering, Qingdao University of Science and Technology, Qingdao 266061, China
  • Received:2012-10-24 Revised:2013-04-08 Online:2013-10-25 Published:2013-09-13
  • Contact: Pengcheng ZHAO
  • Supported by:

    Fundamental Research Funds for the Central Universities (No.2012ZZ0059), the National Natural Science Foundation of China (No. E51375173) and the Open
    Fund of State Key Laboratory of Materials Processing and Die & Mould Technology (No. 2011-P02). Part of this work was also a project of Shandong Province Higher Educational Science and Technology Program (No. J12LA16).

Abstract:

Based on the Magneto-Hydro-Dynamic (MHD) theory, a united three-dimensional (3D) transient numerical model is developed to investigate the dynamic behaviors of arc plasma for a magnesium alloy AZ61A gas tungsten arc welding (GTAW) arc. The arc, electrode and workpiece are integrated into one calculation domain to avoid both presumed distribution of the current density at the electrode tip and the assumption of constant conditions of interface between welding arc and workpiece. The distributions of electric potential, current density, magnetic flux density, electromagnetic force, velocity, temperature, and pressure of the arc plasma in the 3D space are analyzed by using the numerical model. Results indicate that the maximum gradient of the electric potential in the whole arc space exists around the electrode tip, where the electric current density, electromagnetic force, and temperature are also the maximum. However, maximum pressure is found at the velocity stagnation, which is above the workpiece. Comparison between predicted temperature and measured one in arc region shows a good agreement.

Key words: GTAW, Arc, MHD theory, Dynamic behavior, Numerical simulation