Silicon carbide-containing mold and facecoat compositions and methods for casting titanium and titanium aluminide alloys
AssigneeGeneral Electric Company
InventorsBernard Patrick BEWLAY, Joan MCKIEVER, Brian Michael ELLIS, Nicholas Vincent MCCLASKY
Life of this patent
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Abstract
The disclosure relates generally to mold compositions and methods of molding and the articles so molded. More specifically, the disclosure relates to silicon carbide-containing mold compositions, silicon carbide-containing intrinsic facecoat compositions, and methods for casting titanium-containing articles, and the titanium-containing articles so molded.
Claims25
A method for forming a mold for casting a titanium-containing article, comprising:
- mixing calcium aluminate and silicon carbide with a liquid to produce a slurry, wherein the percentage of solids in the slurry is about 60% to about 80% by weight of the slurry and a viscosity of the slurry is about 30 to about 1500 centipoise;
- introducing the slurry into a mold cavity that contains a fugitive pattern;
- and
- allowing the slurry to cure in the mold cavity to form the mold for casting the titanium-containing article.
A method for casting titanium and titanium alloys, comprising:
- obtaining an investment casting mold composition comprising calcium aluminate and large scale aluminum oxide, wherein the calcium aluminate and alumina are combined with a liquid and silicon carbide to produce a final calcium aluminate/liquid mixture slurry, and wherein the solids in the final mixture is about 70% to about 95% by weight of the slurry;
- pouring said investment casting mold composition into a vessel containing a fugitive pattern;
- curing said investment casting mold composition;
- removing said fugitive pattern from the mold;
- firing the mold;
- preheating the mold to a mold casting temperature;
- pouring molten titanium or titanium alloy into the heated mold;
- solidifying the molten titanium or titanium alloy;
- forming a solidified titanium or titanium alloy casting;
- and
- removing the solidified titanium or titanium alloy casting from the mold.
A turbine blade produced by the process, comprising:
- providing an investment casting mold, said mold comprising calcium aluminate, silicon carbide and aluminum oxide;
- pouring molten titanium or titanium alloy into the mold;
- solidifying the molten titanium or titanium alloy;
- forming a solidified titanium or titanium alloy casting;
- and
- removing the solidified titanium or titanium alloy casting from the mold to produce the turbine blade, wherein the turbine blade has an average roughness, Ra, of less than 20 across at least a portion of its surface area.
A method for manufacturing a turbine component, comprising:
- making a mold from a mixture comprising calcium aluminate, calcium dialuminate, silicon carbide, mayenite and water, wherein the silicon carbide is present at about 15% to about 45% by weight;
- firing the mold;
- pouring molten titanium or titanium alloy into the mold;
- solidifying the molten titanium or titanium alloy to form a solidified casting;
- and
- removing the casting from the mold.
Dependencies are inferred from the claim text.