| 摘要 |
PURPOSE: A method for manufacturing bearing steel is provided which improves fatigue life of the bearing steel at high temperature and contaminated environment by increasing amount of residual austenite in an alloy in which carbide forming and stabilizing elements are supplemented and micronizing structure of the alloy. CONSTITUTION: The method comprises the steps of controlling carbon concentration on the surface of the steel slab to 0.9 to 1.2 wt.% by carburizing a steel slab comprising 0.30 to 0.50 wt.% of C, 1.20 to 2.00 wt.% of Si, 1.50 to 2.50 wt.% of Mn, 1.1 to 1.30 wt.% of Cr, 0.30 to 0.50 wt.% of V, 0.030 to 0.050 wt.% of Al, 0.020 to 0.030 wt.% of N and a balance of Fe and other inevitable impurities; nitriding the carburized steel slab in the temperature range of 870 to 910 deg.C so that the total concentration of carbon and nitrogen on the surface of the steel slab is maintained to 1.2 to 1.7 wt.%; first quenching the nitrided steel slab; and second quenching the first quenched steel slab in the temperature range of 830 to 860 deg.C, wherein amount of residual austenite on the surface of the bearing steel is 25 to 50 vol.%.
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