New Highly-Processable, High-Strength, High-Durability, Temperature-Resistant Gear Steels

QuesTek Innovations presents an update on its new Ferrium® C61™ and Ferrium C64™ gear steels. These highly-processable steels exhibit excellent hardenability, and were explicitly designed to leverage the advantages of vacuum carburization. Ferrium C61 exhibits both excellent surface fatigue and core properties (225 ksi yield strength, 240 ksi ultimate tensile strength, 130 ksi•√in fracture toughness), and is a good candidate for integral gear/shaft applications where maximum torque transfer with minimum weight is tantamount. Ferrium C64 exhibits excellent surface hardness (64+ HRC after vacuum carburization), with the potential for significantly better surface fatigue performance as compared to incumbent gear steels such as AISI 9310 (AMS 6265) and Pyrowear® Alloy 53 (AMS 6308). The final tempering temperature of both C61 and C64 (900-950°F) is 400-600°F higher than most incumbent gear steels, providing superior thermal stability in high-temperature environments and “oil-out” emergency conditions. QuesTek’s Ferrium C61 and C64 are commercially-available from Latrobe Specialty Steel.

Data from multiple production ingots will be presented including tensile tests, fracture toughness, axial fatigue tests, contact fatigue tests, bending fatigue tests, and vacuum carburization process optimization results. Progress towards Aerospace Material Specification (AMS) alloy certification for Ferrium C61 (expected in 2010) and C64 will be summarized, and a review of applications underway (including rotorcraft applications) of both steels will be presented.