Study On Simulation Analysis Of N₂-Ar Protecting TIG Welding Arc

N₂-Ar protecting TIG welding arc has been took into accounted for its peculiarity both N₂ protecting TIG welding arc and Ar protecting TIG welding arc and high capacity density. In this article ANSYS software are used to numerical analyze of N₂-Ar protecting TIG welding arc , and electric and thermal peculiarities of arc are proved by experiments at the same time.An axisymmetric mathematical model of N₂-Ar protecting TIG welding arc is developed according to the theory of magnetic fluid dynamics and the welding arc may be defined by fluid dynamics equation and Maxwell equation. Heat transfer and fluid flow of welding arc are analyzed basing on mathematical model.Actual sharp shape of cathode and reasonable boundary conditions and nonlinear character of physical parameter of argon gas and nitrogen gas are adopted in the model. In the model cathode and arc column are conducted together in calculation on electric field, and the assumption method on current distribution density on cathode tip has not been used. Geometry models about electric field, magnetic field and plasma fluid field are developed respectively. Modularization is adopted in ANSYS analysis and the analysis results from these fields are repeatedly called each other until satisfactory level.Elevated temperature method is used to measure the thermal power and electrical properties of welding arc. The result shows that the electric voltage increased with the enhancement of N₂ content, and the calculation on thermal power indicated with the enhancement of N₂ content, not only the total thermal power of arc increased, but also the ratio of anode thermal power to total thermal power increased. This result certified that N₂-Ar protecting TIG welding arc has high thermal power peculiarity.The simulation analysis calculated result shows that with the enhancement of N₂ content, the temperature of arc , the current density of arc and the velocity of plasma increased also, and similar with experiment results. The special vector function of ANSYS makes the motion of particle inside arc plasma and the practical distribution of many kind of field very visual.Analyze on N₂-Ar protecting TIG welding arc gives a bases foundation for realizing virtual fabrication and provides important boundary conditions about current density distribution and arc pressure distribution for studying welding pool behavior.