Adjusted Nitrogen Alloyed Stainless Steel with Optimized Thermal Processing for Superior Balanced Performance

The materials used in Navy aircraft are prone to the harsh corrosive environment in which the aircraft operate. The corrosion protection of high performance bearing and gear steels without a decrease in mechanical and tribological properties is critical for Navy equipment readiness. Because of the insufficient corrosion resistance of current bearing and gear materials, the Navy developed corrosion inhibited oils for aircraft propulsion systems. The corrosion inhibitors in these oils limit their boundary lubrication (tribology) performance which limits the growth in power density needed for propulsion engine and gearbox systems. The purpose of this SBIR is to develop new high strength, corrosion resistant, wear resistant, scuffing resistant, rolling contact fatigue resistant stainless steels suitable for use in gears and bearings. These new steels are high chromium secondary hardening steels in which the secondary hardening response is enhanced by additions of cobalt and silicon. This SBIR will also utilize advanced surface modification techniques (i.e., low temperature carburizing and induction surface hardening) to further enhance the corrosion, mechanical and tribological properties of currently used bearing steels (e.g., Pyrowear 675, CX13VDW) and high nitrogen martensitic stainless steels (e.g., XD15NW) as well as the new ultra high strength stainless steels developed in this SBIR.