Magnetic-enhanced common conductive channel characteristics of two-electrode TIG

In this paper, a self-designed cusp external magnetic field (EMF) was employed to assist the two-electrode TIG (T-TIG), and its common conductive channel characteristics were aimed to optimize the energy distribution of T-TIG. The influences of the cusp EMF on arc morphology, arc plasma information, and arc pressure of T-TIG were respectively analyzed based on a high-speed camera, spectrograph, and pressure sensor. The results showed that the cusp EMF could compress T-TIG in the direction parallel to the array of two electrodes of T-TIG, and thus, a common conductive channel with stronger brightness and higher stiffness was obtained. Besides, by applied cusp EMF, the electron temperature and electron density of the common conductive channel of T-TIG were increased, and in the radial, the distributions of electron temperature and electron density of T-TIG were more concentrated. Under the condition of welding current of 40 A + 40 A, the electron density on the central axis of T-TIG could be increased by 16% by applied cusp EMF with a 30 A excitation current. In addition, the enhanced common conductive channel characteristics of T-TIG by the cusp EMF caused the arc pressure on the central axis of T-TIG to be increased by 14%, which was beneficial to improve the weld penetration.