Krosakiharima Corporation

Masaki Yamamoto

Arito Mizobe

Joji Kurisu

Tatsuya Oouchi

Kento Furukawa

Tetsuo Tsuduki

It is intended to suppress flaming and smoking due to combustion of combustible substances in a certain-shaped joint material, while maintaining hot sealability of the certain-shaped joint material. A certain-shaped joint material for hot installation is obtained by: adding organic additives to a blend in a combined amount of 26 mass % to 50 mass %, with respect to and in addition to 100 mass % of the blend, wherein the blend comprises 50 mass % to 90 mass % of gibbsite type aluminum hydroxide raw material, 1 mass % to 9 mass % of clay, and 9 mass % to 23 mass % of graphite, with the remainder mainly composed of an additional refractory raw material; and subjecting the resulting mixture to kneading, forming and drying.

Certain-shaped joint material for hot installation

With a view to adding, to an upper nozzle formed with a bore having a shape capable of creating a less energy loss or smooth (constant) molten steel flow to suppress the occurrence of adhesion of inclusions and metals in molten steel, a gas injection function to thereby further suppress the occurrence of the adhesion, the present invention provides a method of using an upper nozzle configured to have a cross-sectional shape of a wall surface defining the bore, taken along an axis of the bore, comprising a curve represented by the following formula: log(r (z))=(1/n)&#xd7;log((H+L)/(H+z))+log(r (L)) (n=1.5 to 6), where: L is a length of the upper nozzle; H is a calculational hydrostatic head height; and r (z) is an inner radius of the bore at a position downwardly away from an upper edge of the bore by a distance z. The method comprises using the upper nozzle in such a manner as to satisfy the following relationship: R&#x2266;4.3&#xd7;V, where Ris a gas rate defined as a volume ratio of a flow rate Q(Nl/s) of injection gas to a flow rate Q(l/s) of molten steel flowing through the bore (R=(Q/Q)&#xd7;100(%)), and Vis a flow speed of the molten steel at a lower edge of the upper nozzle.

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Fukkuoka, Japan

Masaki Yamamoto