Low Maintenance Helicopter Tail Driveshaft Hanger Bearing Navy SBIR FY2012.1 Sol No.: Navy SBIR FY2012.1 Topic No.: N121-031 Topic Title: Low Maintenance Helicopter Tail Driveshaft Hanger Bearing Proposal No.: N121-031-0338 Firm: QuesTek Innovations LLC 1820 Ridge Avenue Evanston, Illinois 60201-3621 Contact: Christopher Kern Phone: (847) 425-8232 Web Site: www.questek.com Abstract: A high-performance, stainless bearing steel is needed to reduce maintenance inspection intervals and increase life of MH-60S hanger bearings operating in a corrosive environment. Available bearing alloys such as 440C, Pyrowear 675, etc. provide some level of corrosion resistance, but ultimately, corrosion resistance is compromised due to suboptimal case carburized microstructure, low matrix chromium content, low pitting resistance, and use of large Cr-rich primary carbides as strengthening mechanisms. QuesTek Innovations LLC proposes to evaluate alternate bearing materials to 440C for use in corrosive environments. Using a systems design approach, the materials will be selected based on anticipated corrosion and wear resistance. In addition to potential alloys available, QuesTek is currently working on a developmental alloy that meets the materials substitution requirements. Upon material down selection of candidate alloys with the TPOC, laboratory corrosion (via salt fog chamber) and wear testing (via pin-on-disc) will be completed to determine the most suitable replacement material for 440C. In addition to a material replacement, QuesTek will work to evaluate the need for potential redesign of the hanger bearing assembly due to debris entry. If required, a component redesign will be completed in the Phase II when demonstration components will be manufactured and bench tested. Benefits: Successful completion of the program will result in demonstration of an alloy that provides improved corrosion resistance compared to 440C with wear resistance of M50. There is a significant market for an alloy with these characteristics in both military and commercial applications. This technology will result in extending life and performance of mechanical systems while reducing unscheduled maintenance and repairs. This technology would be highly beneficial to any mechanical system required to operate in a corrosive environment. Non-aerospace applications may include improved medical devices, hand tools, and applications that may benefit from a unique combination of fatigue, wear, and corrosion resistance. Return