| 摘要 |
PROBLEM TO BE SOLVED: To manufacture a long-life rolling bearing by suppressing an excessively carburized structure from being formed and also excellently controlling a carbon concentration, etc., of a surface in a heat treatment for manufacturing the rolling bearing.SOLUTION: After a first diffusion treatment for diffusing nitrogen after subjecting a steel material treated into a shape of a bearing ring or a rolling element to vacuum carburization and a second diffusion treatment using carburization gas and ammonia gas, hardening and tempering are carried out so that a carbon concentration, a nitrogen concentration, a hardness, and a retained austenite amount of a surface, the total area rate of carbide, nitride, and carbonitride in a region corresponding to 1% of a rolling element diameter from the surface, and the rate of carbide, nitride, and carbonitride of 0.5 μm or less in particle size have specific values. A heat treatment apparatus for that includes a vacuum carburization chamber, a first diffusion chamber, a second diffusion chamber, a cooling treatment chamber, and a carrier for carrying a work to the treatment chambers. |
