The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 15, 2000
Filed:
Jan. 07, 1997
Mark Edwin Springgate, Portland, OR (US);
Douglas Gene Nikolas, Battleground, WA (US);
David H Sturgis, Boring, OR (US);
Mehrdad Yasrebi, Clackamas, OR (US);
Precision Castparts Corp., Portland, OR (US);
Abstract
Investment casting shells, methods for their manufacture and methods for casting metals and alloys using such shells are disclosed. One feature of the shells is that the facecoat plus interior backup layers are purposefully designed to have substantially similar coefficients of thermal expansion to the seal dip layers. This helps reduce the occurrence of dimensional casting defects caused by differential thermal expansions of the layers comprising the shell. One embodiment of such a shell comprises a facecoat, plural interior backup layers and plural intermediate backup layers wherein at least one of the plural intermediate backup layers comprises a material capable of undergoing a volumetric transformation during cool down, and wherein the seal-dip layers have a coefficient of thermal expansion that varies from the coefficient of thermal expansion of the facecoat and interior backup layers by less than about 10 percent. A particular embodiment of the method is useful for investment casting aluminides, particularly TiAl, using a shell having an alumina facecoat.