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US 5,014,763 AGranted
Method of making ceramic cores
AssigneeHowmet Corporation
InventorGregory R. Frank
Life of this patent
Estimating the term…
Abstract
A novel method of making a ceramic core for use in casting a metal component includes freezing a ceramic slurry comprising a ceramic powder filler, a freezable liquid and a gelling agent in a mold to form a frozen core shaped body. The frozen core shaped body is removed from the mold and thawed to room temperature. A high viscosity gel is provided in the core shaped body at room temperature that is strong enough to retain the core shape until the body can be fired to form a porous, sintered ceramic core. The gel present at room temperature may be formed as the ceramic slurry is cooled in the mold cavity to form the frozen article shaped body and/or as the frozen core shaped body is thawed to room temperature.
Claims27
A method of making a ceramic core useful in the casting of molten metal therearound, comprising the steps of:
- (a) forming a ceramic slurry of a freezable liquid, a ceramic powder and a gelling agent,
- (b) forming the ceramic slurry into a core shaped body including:
- (1) shaping the ceramic slurry into a core shaped body by introducing the slurry into a core shaped mold cavity and reducing the temperature of the slurry at least to the freezing temperature of said liquid to freeze the slurry in the mold cavity and form a frozen core shaped body therein,
- (2) removing the frozen core shaped body from the mold cavity,
- (3) raising the temperature of the frozen core shaped body after removal from the mold cavity to an ambient temperature above the freezing temperature,
- (4) gelling the gelling agent and the liquid existing at a temperature above the freezing temperature such that a gel is present in the core shaped body at the ambient temperature to retain the freeze formed core shape at the ambient temperature, and
- (c) heating the core shaped body after step (b) to form a sintered ceramic core.
4 more elements
A method of making a ceramic core useful in the casting of molten metal therearound, comprising the steps o:
- (a) forming a ceramic slurry of water, ceramic powder and a water soluble gelling agent,
- (b) forming the ceramic slurry into a core shaped body including:
- (1) shaping the ceramic slurry into a core shaped body by injecting the slurry into a core shaped mold cavity and reducing the temperature of the slurry at least to the freezing temperature of water to freeze the slurry in the mold cavity and form a frozen core shaped body therein,
- (2) removing the frozen core shaped body from the mold cavity,
- (3) thawing the frozen core shaped body to raise its temperature to room temperature,
- (4) gelling the gelling agent and the liquid existing as the temperature of the core shaped body is raised from the freezing temperature to room temperature in step (b) (3) such that a gel is present in the core shaped body at room temperature effective to retain the freeze formed core shape at room temperature, and
- (c) heating the core shaped body after step (b) to form a sintered ceramic core.
4 more elements
A method of making a ceramic core useful in the casting of molten metal therearound, comprising the steps of:
- (a) forming a ceramic slurry of a freezable liquid, a ceramic powder and a protein gelling agent that is soluble in the liquid and exhibits gelling in solution in said liquid at about room temperature and below to the freezing temperature of said liquid,
- (b) forming the ceramic slurry into a core shaped body including:
- (1) shaping the slurry into an article shaped body by introducing the slurry into an article shaped mold cavity and reducing the temperature of the slurry at least to the freezing temperature of said liquid to freeze the slurry in the mold cavity and form a frozen article shaped body therein,
- (2) removing the frozen core shaped body from the mold cavity,
- (3) raising the temperature of the frozen core shaped body to room temperature after removal from the mold cavity,
- (4) gelling the liquid and the gelling agent at a temperature above the freezing temperature such that a gel is present in the article shaped body at said room temperature to retain the freeze formed article shape at said room temperature, and
- (c) heating the core shaped body after step (b) to form a sintered ceramic core.
4 more elements
A method of making a ceramic core useful in the casting of molten metal therearound, comprising the steps of:
- (a) forming a ceramic slurry of a freezable liquid, a ceramic powder including a fluxing agent, and a gelling agent,
- (b) forming the ceramic slurry into a core shaped body including:
- (1) shaping the slurry into an article shaped body by introducing the slurry into an article shaped mold cavity and reducing the temperature of the slurry at least to the freezing temperature of said liquid to freeze the slurry in the mold cavity and form a frozen article shaped body therein,
- (2) removing the frozen core shaped body from the mold cavity,
- (3) raising the temperature of the frozen core shaped body after removal from the mold cavity to an ambient temperature above the freezing temperature,
- (4) gelling the liquid and the gelling agent at a temperature above the freezing temperature such that a gel is present in the article shaped body at the ambient temperature to retain the freeze formed article shape at the ambient temperature, and
- (c) heating the core shaped body after step (b) to form a sintered ceramic core.
4 more elements
A method of making a ceramic core useful in the casting of molten metal therearound, comprising the steps of:
- (a) forming a quantity of a ceramic slurry comprising a freezable liquid, a ceramic powder and a gelling agent,
- (b) forming a portion of the ceramic slurry into a core shaped body including:
- (1) shaping said portion of the slurry into an article shaped body by introducing the slurry into an article shaped mold cavity and reducing the temperature of the slurry at least to the freezing temperature of said liquid to freeze the slurry in the mold cavity and form a frozen article shaped body therein,
- (2) removing the frozen core shaped body from the mold cavity,
- (3) returning the frozen core shaped body to the quantity of the ceramic slurry for remixing therewith,
- (c) shaping a portion of the remixed ceramic slurry into another core shaped body by
- (1) introducing said portion of the remixed ceramic slurry into a core shaped mold cavity and reducing the temperature thereof at least to the freezing temperature of said liquid to freeze the remixed slurry in the mold cavity and form another frozen core shaped body therein,
- (2) removing said another frozen core shaped body from the mold cavity,
- (3) raising the temperature of said another frozen core shaped body after removal from the mold cavity to an ambient temperature above the freezing temperature,
- (4) gelling the liquid and the gelling agent at a temperature above the freezing temperature such that a gel is present in said another core shaped body at the ambient temperature to retain the freeze formed core shape at the ambient temperature, and
- (d) heating said another core shaped body after step (c) to form a sintered ceramic core.
8 more elements
A method of making a ceramic core useful in the casting of molten metal therearound, comprising the steps of:
- (a) forming a ceramic slurry of a freezable liquid, a ceramic powder and a gelling agent,
- (b) forming the ceramic slurry into a core shaped body including:
- (1) shaping the ceramic slurry into a core shaped body by introducing the slurry into a core shaped mold cavity and reducing the temperature of the slurry at least to the freezing temperature of said liquid to freeze the slurry in the mold cavity and form a frozen core shaped body therein,
- (2) removing the frozen core shaped body from the mold cavity,
- (3) raising the temperature of the frozen core shaped body after removal from the mold cavity to an ambient temperature above the freezing temperature,
- (4) gelling the liquid and the gelling agent at a temperature above the freezing temperature such that a gel is present in the article shaped body at the ambient temperature to retain the freeze formed article shape at the ambient temperature,
- (c) removing any flash and parting line formed on the frozen core shaped body by step (b) (1) after the temperature of the core shaped body is raised to said ambient temperature, and
- (d) heating the core shaped body after step (c) to form a sintered ceramic core.
5 more elements
Dependencies are inferred from the claim text.