Operating temperatures in many bearing applications exceed 100 °C. Conventional bearing steel (SAE52100,SAE5120,Etc.) will begin to experience a reduction in life due to dimensional instability, and reduced surface hardness, at these temperatures.
High speed tool steel (such as AISI-M50) can operate in temperatures up to 300°C but is very costly. SAE52100 can be heat stabilized up to 300°C to improve the dimensional stability, but this process can severely decrease the surface hardness and fatigue life.
There are many applications where the high operating temperature is greater than 100°C but less than 200°C. A new material has been developed, based on SAE52100, with improved dimensional stability, and surface hardness, for this medium operating temperature range.