| 摘要 |
PURPOSE:To improve the durability of an upper nozzle to be used for a sliding nozzle for controlling the flow rate of molten steel and to reduce its cost by varying the materials of the peripheral part of a nozzle hole and the outer edge thereof. CONSTITUTION:The materials of the peripheral part (important part) 1 of the nozzle hole 3 through which the molten steel passes and the outer edge (non- important part) 2 thereof are varied. The upper nozzle for the sliding nozzle constituted in such a manner is produced by firing. The peripheral part 1 of the hole and the outer edge 2 thereof are simultaneously molded at the time of molding without interposing mortar, refractories, etc., into the joint part thereof. Alumina carbon, high alumina, magnesia, zirconia and other refractories are selected as the refractory materials for constituting the nozzle bricks and the combinations of these materials are not restricted. As a result, a contribution is made to the reduction of the initial cost in steel making process. |
