JPS5775263A - Charging nozzle for molten metal - Google Patents

Abstract

PURPOSE:To prevent a temp. drop of molten steel, by constructing the upper and lower end parts of a nozzle with electric-conductive refractory materials and the central part in the axial direction with double construction of inside and outside layers whose inside and outside layers constitute of resistance-heating refractory material and nonconductive refractory material respectively. CONSTITUTION:Refractory materials constituting of Al2O3, SiO2, etc. combined with either of carbon such as carbon black, graphite, etc. and carbide such as SiC, etc. or two of them are used for the upper and lower end parts 1, 1' of a nozzle and for the inside layer 2. Material of lower electric resistivity is used for the upper and lower ends 1, 1' and material of higher one is used for the inside layer 2. Refractory materials constituting of Al2O3, SiO2, etc. are used for the outside layer 3. When the electric current is applied to the upper and lower end parts 1, 1' from a heating electric source 5 through a lead wire 4, a resistance-heating body of the inside layer 2 is heated, and the path of molten metal is heated. By said heating, the temp. drop of the molten metal, passing through the inside of nozzle, is prevented, and uncastable troubles caused by a solidification of the molten metal never occur.