Numerical Simulations of Mould Electromagnetic Stirring for Round Bloom Strands

Abstract

For continuous casting of steel the flow inside the liquid core is important for the quality of the end product. Optimal velocities at the solidification front are desired to enhance a transition from columnar to equiaxed solidification. Other benefits are the reduction of inclusions and segregations. In-mould electromagnetic stirring (M-EMS) is a way to achieve these velocities. It is a widely used tool to modify the flow in round bloom strands and is used for most products at Voestalpine Stahl Donawitz. Because measurements at the plant are complicated and physical models are difficult or expensive to build, numerical simulations are nearly the only applicable way to gain insight in the flow in the liquid core of the strand. In this work the full coupling between flow field and magnetic field is considered. While the flow is calculated using a finite volume CFD-solver, the magnetic field is simulated with a finite element solver. The temperature distribution in the mould has a large impact on the shielding effect and hence modifies the magnetic flux density and Lorentz-force density inside the mould. The results will be compared with other (simpler) methods that are commonly used in the literature.