| Abstract Scope |
Traditional bearing microstructures primarily consist of a martensitic structure formed using a high carbon alloy or a case hardening process. More recently, bearings have been manufactured with bainitic microstructures using a process known as austempering. Unlike the athermal transformation process by which martensite forms, bainite is produced from an isothermal transformation process. This cost-effective isothermal transformation process leads to improved heat treat part growth and distortion characteristics, while still providing excellent rolling contact fatigue performance. Using a combination of athermal martensitic and isothermal bainitic transformation processes, enhancements to bearing performance and processing can be achieved. Presented in this paper are multiple methods of heat-treating high carbon bearing steels, associated microstructures produced, component growth and distortion characteristics and demonstrated bearing performance improvement. |