Ferrium® C64™

Ferrium C64 is a premium-quality steel that offers good fracture toughness, high fatigue strength, high core strength, high temperature resistance and high hardenability, and which can achieve surface (i.e. case) hardness up to 62-64 Rockwell “C” (HRC) via carburizing. It was designed to permit use of low-pressure (vacuum) carburization technology with a direct low pressure gas quench. Applications can include armor plate, bearings, actuators, gears, driveshafts, and power transmission components where durability, compactness, weight savings, high temperature resistance or high surface fatigue resistance is valued.

Want even greater fracture toughness?  See Ferrium C61.

Want even greater strength and can tolerate less surface hardness?  See Ferrium M54.

Benefits

Benefits of using C64 vs. alloys such as Pyrowear® Alloy 53 ("X53"), 9310 or 8620 for power transmission applications can include:

• Smaller, lighter-weight gears (or greater throughput). Gears and gearboxes using C64 can handle approximately 15% higher loads than comparable designs using traditional materials, or be reduced in size and weight by comparable amounts, due in part to C64's excellent surface contact fatigue resistance and bending fatigue resistance. Conventional gear steels such as 9310 or 8620 cannot typically achieve 62-64 Rockwell “C” Hardness case hardness with a fatigue-resistant microstructure. 
• Smaller, lighter-weight driveshafts (or greater throughput). Integral driveshafts (e.g. with integral gears) using C64 can handle approximately 20-25% higher loads than comparable driveshafts using traditional materials, or be reduced in size and weight by comparable amounts. C64’s core UTS of 229 ksi is a ~31% increase vs. 9310, for example. 
• Reduced manufacturing times and costs, with increased flexibility and control. C64 was designed to resist grain growth even at high temperatures, have high hardenability, and use vacuum carburizing with a direct low pressure gas quench, to thus: maintain good properties in large, thick-sectioned components (even with vacuum carburizing); reduce final machining/finishing costs by eliminating intergranular oxide formation and reducing quench distortion; eliminate the time, expense, equipment and non-uniformity of the traditional after-carburizing oil quench “hardening” step; and permit “dial-in” control of carburized case hardness profiles.

• Superior high temperature operability and survivability such as in oil-out emergency conditions or high-temperature environmments. The 925°F tempering temperature of C64 is 400-600°F higher than most incumbent alloys, yielding superior thermal stability and allowing gearboxes to run hotter (thus reducing cooling system weight, size, drag, etc.).

Licensed Supplier / C64 Price and Availability

As shown at left please directly contact our commercial production/sales licensee Latrobe Specialty Metals Company for C64 material pricing, availability and information.

Technical Assistance

If you have a specific application engineering or technical question that is not answered by our licensee's resources and the additional information below, then feel free to Contact Us.

Design and Development Background

We computationally designed and developed C64 under NAVAIR-funded STTR Phase I and Phase II projects, in direct response to NAVAIR’s solicitation N05-T006 for improved performance, power density and manufacturability of rotorcraft transmissions when compared to using incumbent carburized gear steels.

In 2011 QuesTek announced a subcontract from Bell Helicopter to jointly evaluate the application of C64 for helicopter gears, as part of the $30 million Technology Investment Agreement awarded to Bell by the U.S. Army Aviation Applied Technology Directorate to develop state-of-the-art drive system technology under the Army’s Future Advanced Rotorcraft Drive System (FARDS) program. During this subcontract, QuesTek will work with Bell to further develop the thermal processing and finishing processes of C64 to optimize the combination of strength and hardness in the gear case and core.