| 摘要 |
PROBLEM TO BE SOLVED: To achieve a rolling bearing which suppresses occurrence of structural change due to hydrogen intrusion, which can extend a life, and which can configure a rotation supporting unit that can stably operate even under severe service conditions.SOLUTION: A rolling bearing is made of an iron alloy which includes 0.10 to 0.30 mass% of C, 0.2 to 0.5 mass% of Si, 0.2 to 1.2 mass% of Mn, 2.2 to 4.5 mass% of Cr, 0.1 to 1.0 mass% of Mo, and the remainder consists of Fe and inevitable impurities. After carburizing treatment or carbonitriding treatment is carried out at 900 to 1,000°C, diffusion treatment keeping the iron alloy at a temperature higher than the temperature of the carburizing treatment or carbonitriding treatment by 10°C or more is carried out. Then, the iron alloy is kept at 800 to 880°C, and is rapidly cooled. Then, quenching treatment is carried out at 800 to 880°C, and the iron alloy is annealed at 160 to 200°C and slowly cooled. Then, a carburizing layer or a carbonitriding layer is formed on a surface, and a carbon concentration at a position of 50 μm from the surface is set at 1.5 mass% or higher, the maximum grain diameter of carbide is set at 10 μm or less, and a prior austenite grain diameter is set at 20 μm or less. |
