| 摘要 |
1,160,367. Fused magnesium chrome refractories. CORHART REFRACTORIES CO. 7 Oct., 1966 [15 June, 1966], No. 45023/66. Heading C1J. A fused cast magnesia chrome ore refractory has an as manufactured microstructure comprising at least 20% periclase grains, into a granular chrome spinel grains (greater than 40% of all the spinel) within the periclase grains, intergrannular chrome spinel of euhedral-subhedral crystals and an auhedral coating on the periclase, not more than 8% of silicate (which never exceeds 6%) plus fluoride, the majority of the grains being 15 to 1000 Á. and the casting analizing in weight per cent M90 40-78; Cr 2 O 3 10-55; Al 2 O 3 4-30; FeO 1-<25; CaO 1-<5; TiO 2 0-20; SiO 2 0-<5; F 0-<5; their sum being at least 95, and the ratio being at least 2.4. The casting is obtained by an increased solidification rate governed by (I) mould size and shape; (2) amount of dissolved gases, (3) stream temperature and (4) thickness of the mould and the layer of insulating powder surrounding the mould, more than one of these generally being necessary. |
