| 摘要 |
PURPOSE:To simply remove a core by making brittleness of the core using ceramic having the specific transformation point as raw material by cooling a casting to the specific temp. and removing the core. CONSTITUTION:The core for casting is manufactured by using the ceramic executing the t-m transformation from stable t-ZrO2 at high temp. zone to stable m-ZrO2 at room temp. in the range from the room temp. to 77 deg.K (liquid nitrogen temp.) as the core material. By using this core, the metal is cast between outer mold and the core and cooled to the room temp. to form the casting having the aimed shape. Successively, at the same time of or after removing the outer mold, the casting is cooled to 77 deg.K the liquid nitrogen temp., to make the brittleness of the core and to remove the core. By this method, the core can be simply removed and the casting having high accuracy can be produced. |
