Casting of reactive metals into ceramic molds
Core molding composition
Reinforced ceramic investment casting shell mold and method of making such mold
Method and apparatus for making intermetallic castings
Oxidation resistant superalloy castings
Yttria-zirconia slurries and mold facecoats for casting reactive metals Patent #: 5464797
ApplicationNo. 779641 filed on 01/07/1997
US Classes:164/519, With particular refractory material164/361, Shell type mold164/517, With particular material for treating or perfecting casting164/518With particular binder
ExaminersPrimary: Ryan, Patrick
Assistant: Lin, I.-H.
Attorney, Agent or Firm
International ClassesB22C 001/02
AbstractInvestment 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.