Improving the Performance of Navy Helicopter Masts by Using Corrosion-Resistant, Ultra-High-Strength Steel Navy SBIR FY2009.1 Sol No.: Navy SBIR FY2009.1 Topic No.: N091-031 Topic Title: Improving the Performance of Navy Helicopter Masts by Using Corrosion-Resistant, Ultra-High-Strength Steel Proposal No.: N091-031-0330 Firm: QuesTek Innovations LLC 1820 Ridge Avenue Evanston, Illinois 60201-3621 Contact: James Wright Phone: (847) 425-8225 Web Site: www.questek.com Abstract: QuesTek will evaluate the feasibility of using Ferrium S53r as the main rotor shaft mast material in Navy helicopters to eliminate the need for toxic cadmium plating, reduce weight and increase toughness (durability), fatigue resistance, general corrosion resistance and SCC resistance. The alloys currently used for Navy helicopter masts (such as 4340 or 9310) provide high strength but offer limited corrosion resistance, and are typically coated (and re-coated during overhaul) with toxic cadmium plating. S53 is a new ultra-high-strength, corrosion-resistant steel developed by QuesTek with its proprietary Materials by Designr development process. S53 is commercially available from two U.S.-based suppliers and has received industry certifications, including SAE (AMS5922) and MMPDS approvals. In applying S53 to rotorshaft masts, QuesTek will specifically investigate processes to harden the surface of S53 shafts above 54 Rockwell C, to accommodate gears, splines, bearings and other hard contact points. QuesTek will also develop additional design data to describe the frictional characteristics of S53 (such as galling and fretting data) to facilitate the design of the contact point and power transmission portions of the rotor shaft mast. The project will also assess the ability of S53 to meet its expected environmental exposure design requirements. Benefits: Corrosion-related maintenance accounts for about 37% of the Navy's maintenance man-hours, totaling about $4.4 billion per year in corrosion-related costs. Toxic cadmium plating can hurt workers who handle it and can damage the environment. Cadmium plating also increases material processing costs, requires regular repair and maintenance, and is difficult or impossible to apply in locations such as the inner diameter of tubular shafts. If rigorous inspection and overhaul schedules are not met, then safety and reliability can ultimately become a problem. Unlike a coating which is susceptible to damage, Ferrium S53r offers inherent monolithic corrosion resistance and may eliminate the need for cadmium plating. S53 is a potential near-term, drop-in solution which can be competitively obtained from two U.S.-based alloy commercial producers licensed by QuesTek. Masts made of S53 may also transmit additional power for increased payload capacity, or reduce the mast size and weight, because of the high ultimate tensile strength of S53. S53 can be applied to new rotorcraft platforms as well as upgrade existing rotorcraft platforms. In summary, the use of S53 in helicopter masts may reduce costs, extend service life, enhance uptime reliability, increase worker safety and improve environmental protection. Return