Process and apparatus for the molding of shaped articles from a composite metallic refractory material
First Claim
1. A process for molding an article of complex shape from a composite metallic refractory material by a unidirectional solidification of the composite material in a mold, comprising the steps of:
- (a) providing a bath of a heat-exchange liquid metal in the form of a substantially cylindrical column;
(b) heating an upper part of said column above the melting point of said composite material while cooling a lower part of said column below said melting point;
(c) fulling immersing a charge-receiving part of said mold in said bath with the bottom of said mold at an intermediate level between said upper and lower parts at which the bath temperature substantially equals said melting point;
(d) maintaining the immersion of the mold in the bath throughout the process;
(e) introducing said composite material into the mold to form a charge therein heated by the surrounding bath above said melting point; and
(f) controlling the heating of said column to maintain the bath temperature at said intermediate level substantially at said melting point while progressively lowering said mold within the bath with reference to said intermediate level for continuously advancing a solidification front in the composite material from the bottom of said mold to the top of said charge.
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Abstract
Disclosed are a method and apparatus for molding articles in which a highly planar solidification front is desired. A charge of liquefied alloy to be molded into the desired article is placed in a mold and submerged in a heat-exchange bath of liquid metal forming a cylindrical column which is heated in an upper portion and cooled in a lower portion to define an intermediate level at which the bath temperature corresponds to the melting point of the alloy. Upon a progressive lowering of the mold within the bath, a solidification front formed in the alloy at that intermediate level advances from the bottom to the top of the charge.
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Citations
16 Claims
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1. A process for molding an article of complex shape from a composite metallic refractory material by a unidirectional solidification of the composite material in a mold, comprising the steps of:
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(a) providing a bath of a heat-exchange liquid metal in the form of a substantially cylindrical column; (b) heating an upper part of said column above the melting point of said composite material while cooling a lower part of said column below said melting point; (c) fulling immersing a charge-receiving part of said mold in said bath with the bottom of said mold at an intermediate level between said upper and lower parts at which the bath temperature substantially equals said melting point; (d) maintaining the immersion of the mold in the bath throughout the process; (e) introducing said composite material into the mold to form a charge therein heated by the surrounding bath above said melting point; and (f) controlling the heating of said column to maintain the bath temperature at said intermediate level substantially at said melting point while progressively lowering said mold within the bath with reference to said intermediate level for continuously advancing a solidification front in the composite material from the bottom of said mold to the top of said charge. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An apparatus for molding an article of complex shape from a composite metallic refractory material by a unidirectional solidification of the composite material in a mold, comprising:
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an upright container for a bath of heat-exchange liquid metal forming therein a substantially cylindrical column; adjustable heat-generating means surrounding said container and including a heater for raising the temperature of an upper portion of said column above the melting point of said composite material and a cooler for maintaining the temperature of a lower portion of said column below said melting point, said heater and said cooler being vertically separated by a neutral zone; temperature-sensing means in said neutral zone operatively coupled with said heat-generating means for establishing an intermediate level at which the bath temperature substantially equals said melting point; mounting means for supporting a mold immersed in said bath, said mounting means being vertically movable with respect to said heat-generating means and said temperature-sensing means; and drive means coacting with said mounting means for lowering said mold from a starting position, in which the bottom of said mold lies at said intermediate level, to an end position in which a charge formed in said mold from said composite material lies below said intermediate level, said column extending upwardly above said intermediate level to keep said charge fully liquefied in said starting position whereby a solidification front coinciding with said intermediate level advances continuously from the bottom to the top of the charge upon progressive lowering of the mold into said end position. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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Specification