Improved Turbine Engine Bearing Materials And Processes

The VAATE program and other advanced turbine engines require improved bearing materials for better resistance to fatigue, wear and corrosion. Orbital Research proposes a combination of two processing methods to ensure the optimum properties. Starting with a high strength stainless steel (Pyrowear 675) to ensure corrosion resistance, a novel heat treating method will be used that dramatically increases the surface hardness and compressive stresses relative to standard methods. The core properties are not diminished, and may be improved. The part is then coated with titanium nitride to provide enhanced wear resistance. The coating is applied using another novel method that dramatically improves adhesion so that it can withstand the high load, high speed conditions present in advanced turbine engines. In Phase I the improvement in material properties and performance characteristics will be demonstrated, and the process designed for a prototype turbine engine bearing. Properties to be measured include strength, toughness, hardness, wear resistance and fatigue resistance. In Phase II prototype bearings will be fabricated and tested. Initial testing will be completed on high speed, high load bearing test rigs. Subsequent testing will be performed in a turbine engine test stand.