NOZZLE FOR CASTING

PURPOSE:To improve the oxidation resistance of the nozzle for casting consisting of refractory aggregate of oxide refractories or(and) carbide refractories and graphite or(and) amorphous carbon by adding a specific ratio of boride refractories thereto. CONSTITUTION:The retractory aggregate which consists of at least either of the oxide refractories (e.g. alumina, zirconia) or carbide refractories (e.g. silicon carbide) and contains metal (e.g. aluminum) is prepd at needs. This refractory aggregate and the graphite or(and) amorphous carbon are, thereupon, mixed and further, the boride refractories (e.g. zirconium boride) is added at 2 to 10wt.% to the mixture and the mixture is press-molded and is calcined in a reducing atmosphere to produce the nozzle for casting. The boron oxide formed by oxidation of the boride refractories react with the silica, etc., exiting unavoidably in the refractories to form the film having an antioxidation function at the time of hot use and, therefore, the oxidation resistance is improved.