| 摘要 |
PROBLEM TO BE SOLVED: To provide a bearing steel component having rolling fatigue strength more improved than before. SOLUTION: A stock having a prescribed componential composition is subjected to: a hot working step where the total working ratio at 800 to 1,000°C is controlled to≥80%; a cooling step where cooling is performed in the temperature of 700 to 500°C at a cooling rate of≥0.2°C/s; and a secondary working step where≥20% working is performed in the temperature range of 700 to <800°C before the cooling step or≥20% working is performed in the temperature range of an Al transformation point or below after the cooling step. Subsequently, at least a part of the stock is subjected to high frequency heating where a temperature rising rate is≥400°C/s, also, ultimate temperature is≤1,000°C, and retention time is≤5 s once or more. Thus, the bearing steel component is obtained which is characterized in that the average grain diameter of old austenite grains in the quenched structure is 12μm or under, and also the maximum grain diameter is 4 times the average grain diameter or under. COPYRIGHT: (C)2008,JPO&INPIT
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