Patent ID: 6948247

Claim:
A method for producing a cylindrical or needle bearing structure including a rolling raceway having a surface and receiving at least one roller, comprising the steps of: forming the rolling raceway surface, comprising the steps of; carburizing the rolling raceway surface to form a surface carburizing layer; and carbonitriding the rolling raceway surface to form a layer containing 30% to 80% retained austenite contacting the surface carburizing layer providing the cylindrical bearing or the needle bearing; carbonitriding a surface of the roller to produce an amount of retained austenite in a surface layer that is increased by about 30% from an austenite concentration of the roller surface prior to the step of carbonitriding; subjecting the roller to a surface finishing which produces micro concave-convex portions in a random direction; and forming the bearing structure wherein an L 10 life ratio of the bearing structure, when tested using standard lubricant, is greater than or equal to three times an L 10 ratio of a conventional bearing structure.