PURPOSE: To enable the use of the nozzle for continuous casting without preheating by incorporating specific ratios of alumina, graphite, molten silica and cristobalite at a specific ratios in the nozzle, thereby producing the nozzle for continuous casting.
CONSTITUTION: This nozzle is produced by incorporating, by weight%, 30 to 68% alumina, 10 to 37 graphite, 3 to 22 molten silica and 5 to 20 cristobalite therein. While the contents of the alumina and the graphite are nearly the same as the contents in the conventional nozzles, a part of the content of the molten silica is substd. with the cristobalite to lower the modulus of elasticity while the strength is maintained, by which the spalling resistance is improved. The probability that the nozzle cracks is high if the content of the cristobalite is <5%. The strength of the nozzle degrades and breaks if the content exceeds 20%. The service life is ≥7 charges in average.
KURASHINA YUKINOBU
SUZUKI HIROMICHI
