Numerical Simulation Of The Deformation Behavior Of Metal Surface In The Mold Controlled By Magnetic Confinement

In the continuous casting process,the stability of the liquid level within the mold is directly related to the quality of the slab.How to well control the liquid level fluctuation is the key to improve the quality of slab.In this paper,the method of controlling the deformation and fluctuation of the liquid level in the mold by the magnetic pressure constraint is proposed.According to the characteristics of free surface behavior in the mold,two kinds of coils parallel to the width and narrow face of the mold are proposed as the magnetic field generator.The distribution of the magnetic field and the electromagnetic force on the molten steel surface in the mold is studied by numerical simulation method.The results show that the magnetic flux density and electromagnetic force in the area covered by the magnetic field generator are obviously increased,whereas the magnetic flux density and electromagnetic force in the outside covering area of the magnetic field generator are very small.The electromagnetic force in the molten steel is increased with coil current and current frequency increasing.With the same parameters,the magnetic flux density and electromagnetic force generated by the magnetic field generator parallel to the wide face are obviously higher than that generated by the magnetic field generator parallel to the narrow face.The deformation and fluctuation of the liquid level in the molten steel in the mold are analyzed by the two-way coupling procedure of magnetic field and flow field.The liquid level of the molten steel in the mold will be squeezed down by the magnetic pressure in the area covered by the wires,as a result,the molten steel surface of the area not covered by the wires is raised.Simultaneously the surface of liquid steel has some fluctuations.With increase of magnetic flux density and electromagnetic force,the deboss depth of the molten steel and surface fluctuation increase.Due to the action of magnetic confinement,close to the narrow,face the molten steel surface height decreases,which reduce the peak-to-trough slope and suppress shear entrapment of slag,and near the nozzle,the molten steel surface height increase.As a result,the whole surface height is reduced and the surface fluctuations is weakened.With the increase of the electromagnetic force,the stronger the suppress effect on the molten steel surface deformation in the mold,and the higher the surface velocity will be.For different sizes of liquid surface deformation,there should exist suitable magnetic field coverage area to get relatively flat metal level.At the same electromagnetic force,with the increase of continuous casting speed,the inhibition effect of magnetic field on liquid surface is increased.With the increase of nozzle depth and the decrease of outlet angle,the effect of magnetic field on liquid surface deformation is not significant varied.