Nozzle for continuous casting of molten steel
AssigneeToshiba Ceramics Co., Ltd.
InventorsKuniaki Watanabe, Hideo Suzuki
Life of this patent
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Abstract
Silica powder is added to a primary mixture consisting of alumina powder and graphite powder, and is mixed therewith. A binder is added to the resultant secondary mixture and is well mixed therewith. The mixture thus obtained is granulated. The granulated product is placed in a rubber mold, and pressure is applied uniformly thereto to mold it. The molded product is fired but not sintered at a temperature between 850.degree. and 950.degree. C., preferably 900.degree. C., which allows unreacted alumina and silica to remain in the final fired-product. Thus, a nozzle consisting of a fired body having a cavity volume index (the sum of the volume of open and closed pores/the volume of the fired body) of 0.15-0.25 including 6-60% of closed pores therein is manufactured.
Claims8
A nozzle for continuous casting comprising a fired unsintered body having a total volume and a minute cavities volume in the range of 0.1 to 0.25 of the total volume, said minute cavities comprising 6 to 60% closed pores, said closed pores comprising 1 to 10% of the total volume of the fired unsintered body, produced by the process of adding 2 to 30% by weight of silica powder to a primary mixture of 10 to 45% by weight of graphite powder uniformly dispersed in 40 to 88% by weight of alumina powder to obtain a secondary mixture, adding 2 to 30% by weight of a binder to the secondary mixture and kneading said secondary mixture and binder to obtain a final mixture, granulating said final mixture, molding said granulated final mixture in a rubber press to form a molded product, and firing the molded product at a temperature between 850.degree. C. and 950.degree. C. to decompose said binder into a gas to form said fired unsintered body with said closed pores while leaving unreacted alumina and silica in said fired unsintered body on surfaces of said closed pores.
A nozzle for continuous casting molten steel comprising forming a primary mixture of 10 to 45% by weight of graphite powder uniformly dispered in 40 to 88% by weight of alumina powder, adding to said primary mixture 2 to 30% by weight of silica powder to form a secondary mixture, adding 2 to 30% by weight of a binder to the secondary mixture to thereby obtain a final mixture, granulating the final mixture to form a granulated product, molding the granulated product by the use of a rubber press to form a molded product, firing the molded product at a temperature between 850.degree. C. and 950.degree. C., and decomposing said binder into a gas to thereby form a fired unsintered body with closed pores while leaving unreacted alumina and silica in said fired unsintered body on surfaces of said closed pores, the fired unsintered body having a total volume and a minute cavities volume in the range of 0.1 to 0.25 of the total volume, said minute cavities comprising 6 to 60% of said closed pores, said closed pores comprising 1 to 10% of the total volume of the fired unsintered body.
Dependencies are inferred from the claim text.