Heat Treatment Process for Martensitic Stainless Steel Pyrowear 675 for Improved Corrosion Resistance
SourceHigh performance mechanical systems such as bearing and gears in advanced gas turbine engines are required to operate at ever increasing speeds, temperature, and loads. An advanced high temperature case hardened bearing steel, Pyrowear 675, has been developed for these applications. The basic mechanical properties and desired microstructure can be achieved by conventional carburizing techniques; however, corrosion resistance is not substantially better than conventional bearing steels like M50 and 440C. A new thermal process for Pyrowear 675 was developed that provided enhanced corrosion resistance, while maintaining required mechanical properties and microstructure. The thermally processed Pyrowear 675 was characterized for carbon and nitrogen content, corrosion resistance, microstructure, hardness, hot hardness, residual stress, retained austenite, and rolling contact fatigue life.