Numerical simulation study on the characteristics of TIG welding arc with an external longitudinal magnetic field

Studying the characteristics of TIG welding arcs under the influence of an externally applied longitudinal magnetic field through numerical simulation is an important method to improve the stability and processing properties of the welding process. Firstly, a physical model for simulating TIG welding arcs was established based on actual welding experimental conditions. Secondly, based on magnetohydrodynamics, a two-dimensional steady-state control equation of the TIG arc welding process under the influence of an external longitudinal magnetic field was established. Then, under different welding currents and different longitudinal magnetic field intensities, the characteristics of the temperature field, pressure field, and velocity field of the plasma in the TIG welding arc were studied, and the variation laws were obtained. The study found that setting the parameters of longitudinal magnetic field reasonably can increase the stiffness of arc and form a negative pressure zone on the surface of molten pool, which is beneficial to increase the stirring speed of molten pool, refine grains and reduce welding defects.