| 摘要 |
PROBLEM TO BE SOLVED: To reduce the detects on the surface and in the inner part of a cast slab by casting while impressing the integration of a static magnetic field and a shifting magnetic field shifted in the casting direction to molten metal in a mold. SOLUTION: A DC coil 14 for impressing the static magnetic field, an AC coil 15 for impressing the shifting magnetic field and an iron core 13 commonly wound with these coils, are arranged. The static magnetic field in the casting thickness direction with the DC coil 14 and the shifting magnetic field by conducting three phase AC to the AC coil 15 with a different branched different phase, are impressed. The fluidity of the molten metal surface (molten steel surface) 7 is reduced with the static field, the entrapment of solid powder 5 and molten powder 6 is restrained, and the lower stream speed is reduced, the invading depth of an inclusion 11 and a bubble 12 is shallowed. The fluidity of the molten steel at the interface between a solidified shell (cast slab) 9 and the molten steel (molten metal) 10 is activated with a vertical shifting magnetic field to prevent the catching of the inclusion 11 and the bubble 12 into the cast slab. It is desirable that the intensity of the static magnetic field is 0.05-0.8 T at the center in the mold thickness direction and the frequency of the shifting magnetic field and the effective intensity at the molten steel surface position in the long sides of the mold, are 0.1-10 Hz and 0.02-0.2 T, respectively.
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