Honda Motor Co., Ltd.

Nippon Steel Sumitomo Metal Corporation

Mitsuru Fujimoto

Hideki Imataka

Masayuki Horimoto

Gen Kato

A case hardening steel material having a chemical composition consists of, by mass percent, C: 0.15 to 0.23%, Si: 0.01 to 0.15%, Mn: 0.65 to 0.90%, S: 0.010 to 0.030%, Cr: 1.65 to 1.80%, Al: 0.015 to 0.060%, and N: 0.0100 to 0.0250%, further containing, as necessary, one or more kinds selected from Cu and Ni of predetermined amounts, the balance being Fe and impurities; 25&#x2266;Mn/S&#x2266;85, 0.90&#x2266;Cr/(Si+2Mn)&#x2266;1.20, and 1.16Si+0.70Mn+Cr&#x2267;2.20; P, Ti and O in the impurities being P&#x2266;0.020%, Ti&#x2266;0.005%, and O&#x2266;0.0015%; and having a structure consisting of 20 to 70% in an area ratio being ferrite; and the portion other than the ferrite being one or more kinds of pearlite and bainite. The steel material is used suitably as a raw material of the carburized part such as a CVT pulley shaft.

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Saitama, Japan

Mitsuru Fujimoto