Current Magnetic Field and Joule Heating in Electroslag Remelting Processes

摘要

A three-dimensional (3D) finite element model was developed to simulate the current density, magnetic field, electromagnetic force and Joule heating for a system of electrode, slag and ingot in electroslag remelting processes. Especially, the skin effect is taken into account in electromagnetic field model by magnetic vector potential method. Simulated magnetic flux density is compared with experiment and obtained a good agreement. Numerical results show that the skin effect becomes strong and the maximum current occurs at the surface of electrode and ingot, the maximum of electromagnetic force is at the upper surface nearby the electrode in the slag and the maximum of Joule heating is at the interface of electrode and slag. The parametric study shows that the eddy current flow occurs in interior of electrode and ingot if the current frequency is more than 40 Hz. With the increasing of electrode immersion depth or decreasing of slag cap thickness, the maximum of the Joule heating in slag increases.