Predicting transfer behavior of oxygen and sulfur in electroslag remelting process

A transient three-dimensional (3D) comprehensive mathematical model has been developed to understand oxygen and sulfur transfers in electroslag remelting process. The solutions of the mass, momentum, energy and species conservation equations were simultaneously carried out by finite volume method. The Joule heating and Lorentz force were taken into account. The thermochemical and electrochemical transfers of oxygen and sulfur were represented through the application of a metallurgical thermodynamic and kinetic module. In order to obtain the evolution of oxygen activity, the chemical reaction between dissolved aluminum and dissolved oxygen in the metal was included. The comparison between the measured and simulated data indicates that the model can predicate the transfer behavior with an acceptable accuracy. The thermochemical reaction always removes oxygen and sulfur from the metal, while the electrochemical reaction brings oxygen and sulfur back to the metal through the metal droplet-slag interface, and takes them away from the metal through the metal pool-slag interface. The oxygen removal ratio is about 60%, and the contribution of the electrochemical reaction is around 82%. The sulfur removal ratio is approximately 76%, and the contribution of the electrochemical reaction is around 39%.