Refractory material for casting a rare-earth alloy and its production method as well as method for casting the rare-earth alloys

摘要

Rare-earth alloy is cast into a sheet ( 6 ) or the like by using a tundish ( 3, 13 ). The refractory material of the tundish used for casting does not necessitate preheating for improving the flowability of the melt ( 2 ). The refractory material used essentially consists of 70 wt % or more of Al₂O₃ and 30 wt % or less of SiO₂, or 70 wt % or more of ZrO₂ and 30 wt % or less of one or more of Y₂O₃, Ce₂O₃, CaO, MgO, Al₂O₃, TiO₂ and SiO₂. The refractory material has 1 g/cm³ or less of bulk density, has 0.5 kcal/(mh° C.) or less of thermal conductivity in the temperature range of from 1200 to 1400° C., and has 0.5 wt % or less of ratio of ignition weight-loss under the heating condition of 1400° C. for 1 hour.