| 摘要 |
A casting pattern disposed in a molded material and having the configuration of the article to be cast. A core member is located within the outer body member and has the configuration of a cavity to be formed and the casting. The outer body member and the core member are each composed of a material gasifiable substantially without residue upon being subjected to the elevated temperature of a molten casting charge. A first layer of refractory gas permeable material covers the outer body member and remains solid at the elevated temperature of the molten casting charge. A second layer of refractory material covers the entire outer surface of the core member which is exposed to the body member for preventing contact between the casting charge and the core member and being operative to retard the transmission of heat from the molten casting charge to the core member to prevent the gasification of core member until a portion of the metal adjacent the second layer has solidified.
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