| 摘要 |
PROBLEM TO BE SOLVED: To provide a steel which has an excellent rolling fatigue life to prolong further the life of bearings even under the using condition severer than the conventional case, and to provide its production method. SOLUTION: The steel is obtained by successively subjecting a steel stock comprising, by mass, 0.7 to 1.1% C, 0.2 to 2.0% Si, 0.4 to 2.5% Mn, 1.6 to 4.0% Cr, 0.1 to <0.5% Mo, and 0.010 to 0.050% Al, and the balance Fe with inevitable impurities to spheroidizing annealing, quenching, and tempering. The steel has a microstructure consisting of residual cementite with a grain size of 0.05 to 1.5μm and old austenite with a grain size of 30μm after quenching and tempering. COPYRIGHT: (C)2005,JPO&NCIPI
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