| 摘要 |
PROBLEM TO BE SOLVED: To provide a gear which is excellent in low cycle fatigue strength. SOLUTION: The gear excellent in low cycle fatigue strength has a composition containing, by mass, 0.05 to 0.20% C,≤0.7% (not including 0%) Si, 1.41 to 2.0% Si, 1.0 to 2.0% Cr and the balance Fe with inevitable impurities, wherein C concentration in the surface layer of a tooth surface is 0.4 to 0.75%, and a difference between hardness in the surface layer and hardness in a core part is 200 to 400 HV. And the inevitable impurities include P, S, Al and N, and further, respective amounts of P, S, Al and N are e.g. about≤0.015% (not including 0%), about≤0.01% (not including 0%), about≤0.01% (not including 0%) and about≤0.008% (not including 0%), respectively. COPYRIGHT: (C)2009,JPO&INPIT
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