Calcium hexaluminate-containing mold and facecoat compositions and methods for casting titanium and titanium aluminide alloys
AssigneeGeneral Electric Company
InventorsBernard Patrick BEWLAY, Michael James WEIMER, Stephen Francis BANCHERI, Joan MCKIEVER, Brian Michael ELLIS
Life of this patent
Estimating the term…
Abstract
The disclosure relates generally to mold compositions and methods of molding and the articles so molded. More specifically, the disclosure relates to mold compositions, intrinsic facecoat compositions, and methods for casting titanium-containing articles, and the titanium-containing articles so molded, where the mold comprises calcium hexaluminate.
Claims33
A mold for casting a titanium-containing article, comprising:
- a bulk comprising calcium hexaluminate and a calcium aluminate cement, said calcium aluminate cement comprising calcium monoaluminate, calcium dialuminate, and mayenite;
- and
- a cavity for casting a titanium-containing article therein.
A facecoat of a mold that is used for casting a titanium-containing article, said facecoat, comprising:
- calcium hexaluminate, calcium monoaluminate, calcium dialuminate, and mayenite, wherein said facecoat is an intrinsic facecoat, is about 10 microns to about 500 microns thick, and is located between the bulk of the mold and the surface of the mold that opens to the mold cavity.
A method for forming a mold for casting a titanium-containing article, said method comprising:
- providing an initial slurry of a calcium hexaluminate-calcium aluminate cement mixture, wherein the percentage of solids in the initial slurry is about 65% to about 80% and the viscosity of the initial slurry is about 30 to about 300 centipoise;
- adding large-scale oxide particles into the initial slurry to yield a final slurry comprising the calcium hexaluminate-calcium aluminate cement mixture with the large-scale oxide particles such that the percentage of solids in the final slurry is about 75% to about 95%;
- introducing the final slurry into a mold cavity that contains a fugitive pattern;
- and
- allowing the final slurry to cure in the mold cavity to form a mold for casting a titanium-containing article.
A casting method for titanium and titanium alloys, comprising:
- obtaining an investment casting mold composition comprising calcium hexaluminate, calcium aluminate cement, and aluminum oxide, said investment casting mold composition being produced by:
- combining calcium hexaluminate and calcium aluminate cement with a liquid to produce an initial slurry of a calcium hexaluminate-calcium aluminate cement mixture having a percentage of solids of about 65% to about 80% and
- adding large-scale aluminum oxide particles into the initial slurry to yield a final slurry comprising the calcium hexaluminate-calcium aluminate cement mixture with the large-scale aluminum oxide particles such that the percentage of solids in the final slurry is about 75% to about 95%;
- 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 and forming a solidified titanium or titanium alloy casting;
- and
- removing the solidified titanium or titanium alloy casting from the mold.
Dependencies are inferred from the claim text.