In order to improve the cleanliness of steel slabs cast at high speeds, the application of an intense static magnetic field in the continuous caster mold using superconducting magnets was examined for the first time in the world.
Pilot scale experiments using a 5 ton steel melt were carried out. The maximum magnetic field intensity was 1.0 T. To clarify the possibility of high speed casting with a superconducting magnetic brake, casts were made at a maximum speed of 3.0 m/min. Surface and internal inclusions were remarkably reduced by application of the magnetic field. The results showed that the slab quality at a casting speed of 3.0 m/min with a static magnetic field of 1.0 T is better than that in conventional casting at 1.2 m/min without magnetic field control. Thus, these experiments confirmed the possibility of high speed casting of steel using superconducting magnets.
A numerical analysis clarified the effect of the intensity of the magnetic field on the downward velocity of the molten steel in the mold. The calculated results were in good agreement with experimental data. The reduction in internal inclusions by the application of a strong magnetic field can be convincingly explained by the reduction in the downward velocity obtained in this simulation.
