| 摘要 |
PROBLEM TO BE SOLVED: To provide a gear which can be produced at a low cost, and has excellent bending strength of a dedendum and pitting resistance, and to provide a production method therefor. SOLUTION: Steel having a composition containing, by weight, 0.10 to 0.30% C, 0.50 to 1.50% Si, 0.30 to 1.00% Mn, <=0.035% P, <=0.035% S, 0.20 to 0.85% Cr, 0.35 to 0.80% Mo, 0.020 to 0.060% Al, 0.0080 to 0.0200% N and <=0.010% Ti, and the balance Fe with impurities is subjected to carburization and shot peening treatment. The gear has a carburized layer having a C concentration of >=0.60% and a retained austenite content of <=20%, and the external layer thereof is provided with a carburized abnormal layer whose maximum depth is 2 to 10μm. The area occupied by the carburized abnormal layer in the cross- section from the position of the maximum depth to the surface is >=80%.
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