Modeling of fluid flow, heat transfer and inclusion removal in electroslag remelting process with a rotating electrode

Abstract

A transient 3D integrated model has been developed to investigate the role of a rotating electrode on the improvement of productivity and refining ability in the electroslag remelting process. All essential considerations of the fluid flow, heat transfer, and inclusion removal are incorporated in the model. The electrode melting rate is predicted based on the heat flux from the slag to the electrode. The motion of inclusions is considered and resolved by the Lagrangian approach. The reliability of the model is thoroughly validated against a scale experimental data. Numerical results show that metal droplets tend to separate at the centre of the static electrode tip. With the rotating electrode, metal droplets are however detached by centrifugal force at the outer side of the electrode tip. The highest temperature area also migrates from the outer mold region to the mold centre as the rotating speed increases from 0 to 60 rpm. The averaged electrode melting rates for the four rotating speeds (i.e. 0, 20, 40, and 60 rpm) are 0.02292, 0.02410, 0.02795, and 0.02506 kg/s, respectively. The maximum improvement of productivity with a value of 21.95% is achieved when the rotating speed is 40 rpm. The removal ratio of inclusions is also enhanced by increasing the rotating speed. The impact of the rotating electrode and the enhanced removal mechanism are discussed in detail.