Case Study: QuesTek's Ferrium C64 & Additive Manufacturing Process Make Army Helicopters Tougher, Lighter, and Safer
SituationThe U.S. Army needed to enhance the performance and safety of its helicopters, but the steels they were currently utilizing could not fulfill this goal. The Army sought the development of new rotorcraft gear materials possessing a combination of increased bending and contact fatigue resistance, enhanced core strength with good toughness, higher temperature resistance, and excellent hardenability.This is a unique case study because of its micro and macro-level impact. As you will see, QuesTek solved the Army’s problem by developing a best-class-novel alloy. But the bigger picture is that QuesTek’s advanced additive manufacturing (AM) process has begun blazing the trail for innovation in the aerospace, racing and industrial markets.
ChallengeThe Army’s main pain point was that the lead time for manufacturing gears for testing in Science and Technology (S&T) prototype demonstrators could sometimes take 18 months and required costly, special tooling. Thus, the Army needed a way to develop a new or improved AM process for prototyping aerospace gears.
SolutionQuesTek engineered Ferrium® C64®, a novel high-performance gear steel that provides a combination of high core-strength, toughness, surface hardenability, improved processability (cost and time reduction), and temperature resistance.
Ferrium C64 steel was originally developed under Department of Defense funding and first utilized by the Navy. In 2015, under the Future Advanced Rotorcraft Drive Systems (FARDS) program, the Army contracted with Bell Helicopter and Sikorsky (now Lockheed Martin) to develop their respective next generation gearbox technologies and achieve Future Vertical Lift performance targets.
QuesTek Innovations, who was subcontracted to work with the rotorcraft OEMs on the FARDS program, is uniquely qualified for the following reasons:
- Demonstrated success applying Ferrium® C61 and C64 alloys to gears, effectively replacing legacy gear materials such as 8620, 9310, and Alloy X53 in aerospace and other demanding applications.
- Optimized processing conditions of the C64 steel (e.g., forging, machining, heat treating) to further increase gear performance under both Army and commercial funding.
- Additive Manufacturing innovation: QuesTek had also leveraged its material design expertise to determine optimal compositions and processing conditions for additively manufactured components in a variety of material alloy systems and with a number of AM techniques.
OutcomesThe outcomes of Ferrium C64 applications are numerous:
- With existing steels, the Army’s rotorcraft platforms did not meet the requisite 30-minute oil-out operational duration. However, the Ferrium C64 components lasted through 85 minutes of testing without any signs of failure, successfully demonstrating that the gearbox could exceed the 30-minute loss of lubrication requirement.
- Ferrium C64 enabled an up-to 25% increase in power density over incumbent materials.
- Ferrium C64 enables gearbox designs to become lighter, operate at higher temperatures, and increase safety margins compared to gearboxes manufactured from traditional steels.
- Ferrium C64 is being successfully demonstrated as the best performing gear material available for additive manufacture of gears for aerospace, high performance racing and industrial applications for prototyping and replacement of small legacy gears.
This Ferrium C64 success story, due to QuesTek’s advancement of AM, has far-reaching implications for the aerospace and other industries. These developments promise either the ability to enable those improved designs and/or foster rapid prototyping to reduce lead times in qualification and deployment of future systems.