Sequentially Coupled Simulation of Multiphysical Fields During Twin-Electrode Electroslag Remelting Process

A transient three-dimensional (3D) sequentially coupled mathematical model has been developed to explore multiphysical fields in the twin-electrode electroslag remelting (TE-ESR) furnace. The mechanical APDL module based on the finite element method and the Fluid Dynamics module based on the finite volume method were used to resolve the electromagnetic field and simulate the fluid flow, heat transfer, and solidification process, respectively. The resulting electromagnetic force and Joule heating were incorporated into the source terms of Navier–Stokes and energy conservation equations, respectively. The motion of molten metal droplets and fluctuation of slag/metal interface were tracked by the volume of fluid (VOF) approach. The enthalpy-based technique was employed to simulate the solidification. The results show that the current density is distributed uniformly due to the proximity effect. This is very different from the traditional ESR process during which the skin effect phenomenon is dominated. Besides, the current density is mainly distributed in the slag, only one-fifth flowing through the ingots. The magnitude of velocities in the molten slag is two orders of magnitude higher than those in the steel. The highest temperature zone in the TE-ESR process occurs in the middle of twin-electrode, whereas in the traditional ESR process it occurs beneath the electrode tip. Finally, parametric studies including melting rate, slag thickness, electrode diameter, and center distance have been conducted in detail.