中国物理B ›› 2018, Vol. 27 ›› Issue (3): 34701-034701.doi: 10.1088/1674-1056/27/3/034701

• ELECTROMAGNETISM, OPTICS, ACOUSTICS, HEAT TRANSFER, CLASSICAL MECHANICS, AND FLUID DYNAMICS • 上一篇    下一篇

Numerical analysis of plasma arc physical characteristics under additional constraint of keyhole

Bin Xu(徐斌), Fan Jiang(蒋凡), Shujun Chen(陈树君), Manabu Tanaka(田中学), Shinichi Tashiro(田代真一), Nguyen Van Anh   

  1. 1 Engineering Research Center of Advanced Manufacturing Technology for Automotive Components, Ministry of Education, Beijing 100124, China;
    2 Joining and Welding Research Institute, Osaka University, Osaka 567-0047, Japan
  • 收稿日期:2017-07-30 修回日期:2017-09-23 出版日期:2018-03-05 发布日期:2018-03-05
  • 通讯作者: Fan Jiang E-mail:jiangfan@bjut.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 51505008) and the National Science and Technology Major Project of China (Grant No. 2014ZX04001-171).

Numerical analysis of plasma arc physical characteristics under additional constraint of keyhole

Bin Xu(徐斌)1, Fan Jiang(蒋凡)1, Shujun Chen(陈树君)1, Manabu Tanaka(田中学)2, Shinichi Tashiro(田代真一)2, Nguyen Van Anh2   

  1. 1 Engineering Research Center of Advanced Manufacturing Technology for Automotive Components, Ministry of Education, Beijing 100124, China;
    2 Joining and Welding Research Institute, Osaka University, Osaka 567-0047, Japan
  • Received:2017-07-30 Revised:2017-09-23 Online:2018-03-05 Published:2018-03-05
  • Contact: Fan Jiang E-mail:jiangfan@bjut.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 51505008) and the National Science and Technology Major Project of China (Grant No. 2014ZX04001-171).

摘要: The physical characteristics of a plasma arc affect the stability of the keyhole and weld pool directly during keyhole plasma arc welding (KPAW). There will be significant change for these characteristics because of the interaction between the keyhole weld pool and plasma arc after penetration. Therefore, in order to obtain the temperature field, flow field, and arc pressure of a plasma arc under the reaction of the keyhole, the physical model of a plasma arc with a pre-set keyhole was established. In addition, the tungsten and base metal were established into the calculated domain, which can reflect the effect of plasma arc to weld pool further. Based on magneto hydrodynamics and Maxwell equations, a two-dimensional steady state mathematical model was established. Considering the heat production of anode and cathode, the distribution of temperature field, flow field, welding current density, and plasma arc pressure were solved out by the finite difference method. From the calculated results, it is found that the plasma arc was compressed a second time by the keyhole. This additional constraint results in an obvious rise of the plasma arc pressure and flow velocity at the minimum diameter place of the keyhole, while the temperature field is impacted slightly. Finally, the observational and metallographic experiments are conducted, and the shapes of plasma arc and fusion line agree with the simulated results generally.

关键词: characteristics of plasma arc, interaction of keyhole and plasma arc, pre-set keyhole model, numerical analysis

Abstract: The physical characteristics of a plasma arc affect the stability of the keyhole and weld pool directly during keyhole plasma arc welding (KPAW). There will be significant change for these characteristics because of the interaction between the keyhole weld pool and plasma arc after penetration. Therefore, in order to obtain the temperature field, flow field, and arc pressure of a plasma arc under the reaction of the keyhole, the physical model of a plasma arc with a pre-set keyhole was established. In addition, the tungsten and base metal were established into the calculated domain, which can reflect the effect of plasma arc to weld pool further. Based on magneto hydrodynamics and Maxwell equations, a two-dimensional steady state mathematical model was established. Considering the heat production of anode and cathode, the distribution of temperature field, flow field, welding current density, and plasma arc pressure were solved out by the finite difference method. From the calculated results, it is found that the plasma arc was compressed a second time by the keyhole. This additional constraint results in an obvious rise of the plasma arc pressure and flow velocity at the minimum diameter place of the keyhole, while the temperature field is impacted slightly. Finally, the observational and metallographic experiments are conducted, and the shapes of plasma arc and fusion line agree with the simulated results generally.

Key words: characteristics of plasma arc, interaction of keyhole and plasma arc, pre-set keyhole model, numerical analysis

中图分类号:  (Magnetohydrodynamics and electrohydrodynamics)

  • 47.65.-d
47.75.+f (Relativistic fluid dynamics) 52.25.Dg (Plasma kinetic equations)