| 摘要 |
<p>PURPOSE:To effectively prevent the hydration of a core constituted of a calcia refractory material by coating the core with a high-polymer film having impermeability of H2O molecules and maintaining a vacuum atmosphere in the inside part of the high-polymer film. CONSTITUTION:The calcia refractory material contg. about >=40wt% CaO is molded with other components and, if necessary, a binder and the molding is calcined to a sintered body to form the core or casting mold. Such core or casting mold is coated with the high-polymer film having the impermeability of H2O molecules and the vacuum or drying gaseous atmosphere is maintained in the part inner than the high-polymer film. A HDPE, nylon, etc. are used for the high-polymer film and the film thickness is specified to about 0.03-0.3mm. The core or casting mold is thereby stored satisfactorily at or under an ordinary temp., normal pressure or ordinary humidity. The high- polymer film evaporates in the stage of using such core or casting mold and therefore, a molten metal can be cast without requiring any treatment at all.</p> |
