Abstract Method and apparatus for improving the prodution rate of directionally solidified castings employing an annular mold having one or more molding cavities therein and a pair of heat radiating elements disposed concentrically with the mold, one being located inside and the other being located outside the mold, the heat radiating elements being arranged so that no temperature gradient exists across the mold. A pair of heat sinks is provided, the heat sinks being coaxial with the two heat radiating elements. Means are provided for causing relative movement between the annular mold and the heat radiating elements and the coaxially aligned heat sinks. The annular mold is positioned on a highly heat conductive pedestal or chill. The mold is preheated by the heat radiating elements to a temperature above the solidification temperature of the metal to be cast. After casting, the solidification of the metal progresses upwardly from the chill and the relative movement between the annular mold and the heat radiator-heat sink combination causes the solidification innerface to occur at or near the boundary between the heat radiators and the heat sinks. A baffle is advantageously positioned at this boundary to prevent heat being radiated from the heat radiators to the heat sinks. The solidified metal in passing through the heat sinks radiates heat uniformly to the heat sinks so as to prevent a lateral or radial thermal gradient across the mold during solidification of the metal therein.
The method of producing directionalLy solidified castings which comprises providing an open-ended annular mold, preheating said mold with heat sources located at both the interior and exterior thereof to a temperature above the melting point of the metal to be cast therein, the inner periphery of said annular mold being substantially shielded from direct heat radiation from the exterior heat source, pouring molten metal into said mold to form a continuous annulus of metal, abstracting heat through the open end of said mold to thereby initiate directional solidification of the metal and provide a liquid-solid interface commencing at said open end of said mold and advancing upwardly therein, providing relative movement between said mold and the heat sources, and radiating heat from said mold to a pair of heat sinks during such relative movement, one heat sink being positioned internally and the other externally of said mold to thereby minimize the presence of lateral temperature gradients in the solidifying metal.
Claim 2
Independent Claim
160 words
The method of producing directionalLy solidified castings which comprises providing an open-ended annular mold, preheating said mold with heat sources located at both the interior and exterior thereof to a temperature above the melting point of the metal to be cast therein, the inner periphery of said annular mold being substantially shielded from direct heat radiation from the exterior heat source, pouring molten metal into said mold to form a continuous annulus of metal, abstracting heat through the open end of said mold to thereby initiate directional solidification of the metal and provide a liquid-solid interface commencing at said open end of said mold and advancing upwardly therein, providing relative movement between said mold and the heat sources, and radiating heat from said mold to a pair of heat sinks during such relative movement, one heat sink being positioned internally and the other externally of said mold to thereby minimize the presence of lateral temperature gradients in the solidifying metal.
Claim 3
Dependent Claim
19 words
The method of claim 1 in which said heat sources are stationary and said mold is moved relative thereto.
Claim 4
Dependent Claim
19 words
The method of claim 1 in which said mold is stationary and said heat sources are moved relative thereto.
Claim 5
Dependent Claim
17 words
The method of claim 1 in which said mold includes a plurality of interconnected individual molding cavities.