| 摘要 |
PURPOSE:To secure stirring flow of molten steel in a mold and to prevent the development of stagnation on the molten steel surface by forming holes around submerged part of a submerged nozzle and circulating molten metal supplied from a tundish between opening part and the holes. CONSTITUTION:The molten steel 4 in the tundish 1 is discharged in a mold 20 from the opening part 12. At the submerged part in the molten steel 4 in this submerged nozzle 10, the holes 11 are formed. The molten steel 4 at outside of the submerged nozzle 10 is sucked to inside of the submerged nozzle 10 having low molten steel pressure through these holes 11. By this method, the molten steel flowing motion 15 developed as showing with the arrow marks 30, 31 in the mold 20. By this method, the molten steel 4 near the molten steel surface in the mold 20 is flowed and the stagnation of the molten steel 4 on the molten steel surface is eliminated. Therefore, the molten steel temp. near the molten steel surface is not dropped and the development of the cast slab fault caused by insufficient melting of the powder 21 is restrained. Further, float-up separation of the inclusion becomes good and the floated-up inclusion can be easily absorbed into the powder 21. |
