Nucleated casting for the production of large superalloy ingots

The gas turbine industry is continuously driven to achieve higher thermodynamic efficiency, higher electrical output, and higher reliability through turbine design improvements. The specific component of interest in this article is the turbine wheel, which is the rotating hub on which turbine blades are mounted. The wheel is mechanically loaded by both axial and centrifugal forces and thermally loaded by heat that is conducted from the turbine blades. Currently, the turbine wheel is forged from an ingot that is triple-melted, but nucleated casting is under development as a long-term option. This article describes the investigation into nucleated casting technology for future turbine wheel production. For more information, contact William T. Carter, Jr., General Electric Global Research Center, One Research Circle K1-279MB, Niskayuna, New York 12309, USA; (518) 387-6452; fax (518) 387-5576; e-mail carter@crd.ge.com.