AeroMat Home      Exposition      To Register      ASM Homepage
Back to "Session 4: Superalloys" Search
  Back to "High Temperature Materials" Search  Back to Main Search

Thursday, June 10, 2004 - 2:00 PM
HTM4,2

Low Cost Powder Metallurgy Billet Process

A. Banik, Special Metals, Princeton, KY; K. A. Green, Rolls-Royce Corporation, Indianapolis, IN

Aerospace engine manufacturers are constantly seeking ways to reduce the cost of military and commercial products. Among the most costly of components are the forgings used for turbine disk, spacer and coverplate applications. A unique processing route developed by Special Metals involving slightly subsolidus hot isostatic pressing (SSHIP) combined with press conversion has provided an alternative process route for P/M turbine disk materials. In this work, funded by the AFRL Metals Affordability Initiative (MAI), two P/M nickel-base alloys, R88DT and RR1000, were evaluated for the SSHIP + press forge processing route. This presentation will cover the activities on RR1000, which is in the early stage of production implementation at Rolls-Royce. RR1000 is a high solvus alloy designed for high strength at elevated temperatures in a fine grain form. High strain rate tensile testing on as-SSHIP material displayed ductilities in the 15-25% range, which indicated a need for additional reduction prior to press forging. This was accomplished on subscale test material by a 30% roll reduction, which significantly improved ductility. Fullscale billet conversion was accomplished using an upset operation following SSHIP with no evidence of significant cracking or forging defects. Converted grain size was ASTM 10 and finer. After final press forging, grain size for RR1000 was ASTM 12. Ultrasonic inspection was performed on finished billet and was found to be within acceptable ranges. One billet multiple was isothermally forged into a turbine rim coverplate component. Mechanical properties of this forging will be presented.