Optimized Corrosion Resistant Bearing and Gear Steel Thermal Processing

High performance mechanical systems such as bearings and gears in advanced gas turbine engines for the Joint Strike Fighter (JSF) are required to operate at ever increasing speeds, temperature and loads. An advanced high temperature case hardened bearing steel Pyrowear 675 has been developed for these applications. The basic mechanical properties and desired microstructure can be achieved by conventional carburizing techniques but corrosion resistance is not substantially better than conventional bearing steels like M50 and 440C. In the Phase I program, UES demonstrated the feasibility of an innovative technology that allows Pyrowear 675 to be thermally processed to provide enhanced corrosion resistance while maintaining required mechanical properties and microstructure. In Phase II, the process parameters will be optimized to demonstrate repeatability and process controls on actual bearings and gears. Sub-scale bearing fatigue tests will be conducted in Phase II. Also, the Phase II will demonstrate production ready system capable of thermally processing full scale engine bearings and gears. Full size bearing testing will be conducted in Phase III.