| 摘要 |
PROBLEM TO BE SOLVED: To stably obtain the clear component difference between the surface layer and the inner part of a cast slab, even in the case that the position of the outlet of a nozzle is higher than the position of static magnetic field generating coil, by using the comparatively short pouring nozzle, in a method for casting a composite layer cast slab supplying an added element on the surface layer from the upper part of the molten steel in a mold by using one kind of molten steel, one piece of pouring nozzle and a static magnetic field brake set on the mold. SOLUTION: In the method for producing a composite layer cast slab, supplying the added element on the surface layer from the upper part of the molten steel in the mold by using one piece of pouring nozzle having downward spouting hole per one mold and the static magnetic field brake set on the mold, the position of the nozzle outlet is higher than the position of the coil for generating the static magnetic field and the relation between the average flowing rate at the nozzle outlet and the intensity of magnetic field for static magnetic field brake satisfies the following formula. 0.08≤B/Vq≤0.12, wherein, B: the magnetic flux density (T) at the center in the coil height direction (casting direction) of the static magnetic field brake, Vq: the average flowing speed (m/s) at the spouting hole of the pouring nozzle. COPYRIGHT: (C)2006,JPO&NCIPI
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