| 摘要 |
A metal casting mold formed of a ceramic material. The mold is reusable and is formed of a crystalline ceramic whose coefficient of thermal expansion (in the range 0 DEG to 1000 DEG C.) is between about 0 and 15x10-7/ DEG C./ The mold interior surface includes at least one projection extending towards the mold cavity. The projection is provided with a release (draft) angle of about 6 DEG , tapering away from the base of the projection. Upon pouring, the molten metal surrounds at least a portion of the projection. Upon cooling within the mold, shrinkage of the metal casting against the tapered sides of the projection forces the casting along the projection, toward the latter's tapered end and away from the mold interior surface and thus partially out of the mold cavity. A method of making the ceramic mold of this invention is also disclosed.
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