| 摘要 |
PROBLEM TO BE SOLVED: To provide steel in which cold working property after hot forging is excellent, and the fatigue strength of the non-hardened part, and the rolling resisting strength, pitting resisting strength, wear resistance, fatigue strength or the like of the hardened part are improved. SOLUTION: The steel for induction hardening in which cold working property, the rolling fatigue life of the hardened part and the bending fatigue strength of the non-hardened part are excellent has a composition comprising, by mass, 0.40 to 0.60% C, 0.5 to 0.9% Si, 0.5 to 1.00% Mn,≤0.4% Cr,≤0.035% S and 0.01 to 0.15% V, and the balance Fe with inevitable impurities. The area ratio of ferrite after hot forging is≥15%, the ratio of ferrite in which the ratio of the major axis/minor axis is≤5 accounts for≥30%, and, when the carbon equivalent formula is expressed by formula (1), the carbon equivalent formula satisfies inequality (2): C<SB>eq</SB>=C%+(1/7)Si%+(1/5)Mn%+(1/9)Cr%-(5/7)S%+V% ...(1), and 0.75≤C<SB>eq</SB>≤0.90 ...(2). COPYRIGHT: (C)2005,JPO&NCIPI
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