| 摘要 |
PURPOSE:To provide a titled nozzle which has uniform air permeability and excellent resistance to corrosion and thermal impact and can prevent sticking of deposit by using the granular particles obtd. by mixing and granulating specifically composed alumina and zircon and subjecting the same to a heat treatment at an adequate temp. as aggregate. CONSTITUTION:The granular spherical particles obtd. by mixing 70-98.5wt%. pulverous powder of alumina having about <=100mu average grain size and 1.5- 30% similar pulverous powder of zircon, adding a suitale liquid binder such as sodium polyalkyl allylsulfonate or the like, and subjecting the mixture to tumbling granulation are heat treated at 1,600-1,900 deg.C to obtain high alumina zircon type spherical particles. Alumina type spherical particles having the compsn. of >=89% alumina and <=11% silica are further added and combined to and with said particles according to need. Such particles are used as aggregate and a porous nozzle for casting which prevents deposition and sticking of inclusions such as alumina in a molten metal is obtd. The air permeability of the nozzle is adequately changeable by changing the amt. of said alumina type spherical particles to be compounded. |
