초록 ▼

In making columnar grained castings the shell mold is spaced from the chill plate by a ceramic ring on which the mold is positioned, the ring being made thicker and/or of a different ceramic from the mold to withstand the thermal stress developing while the mold is being heated for pouring, so that

In making columnar grained castings the shell mold is spaced from the chill plate by a ceramic ring on which the mold is positioned, the ring being made thicker and/or of a different ceramic from the mold to withstand the thermal stress developing while the mold is being heated for pouring, so that the mold, not being subjected to such stresses at the base, may be made thinner for producing better castings. In this way the best mold material for the purpose may be selected, as, for example, a material to have no reaction with the alloy and, by lowering the thermal gradient decrease the likelihood of mold failure.

대표청구항 ▼

Apparatus for making columnar grained articles including, a chill plate for controlling the cooling of the mold and alloy therein, a ceramic mold including an article portion having a cavity and a base portion having a cavity communicating with the cavity in the article portion, a spacer ring of pre

Apparatus for making columnar grained articles including, a chill plate for controlling the cooling of the mold and alloy therein, a ceramic mold including an article portion having a cavity and a base portion having a cavity communicating with the cavity in the article portion, a spacer ring of preformed ceramic material separate from the mold and positioned on said chill plate and on which the mold is positioned with the base portion resting on the spacer, said spacer ring and mold providing a continuous cavity from the chill plate through the spacer and into and including the article portion cavity, means surrounding the mold for heating the mold to a temperature substantially as high as the melting point of the alloy to be cast, and the material and thickness of said spacer ring such that said ring is particularly resistant to damage by the steep thermal gradients developed during heating of the mold resting on the ring and simultaneous chilling of the ring by the chill plate, and said spacer ring serving to space the mold from the chill plate to reduce the thermal gradients therein.