| 摘要 |
PROBLEM TO BE SOLVED: To provide a non-heat treated, lead-free steel for rocker arms showing an excellent machinability and nitriding properties and a strength equal to that of a conventionally known heat-treated equivalent. SOLUTION: The steel contains 0.1-0.5% C, 0.01-2.5% Si, 0.1-3.5% Mn, 0.001-0.2% P, 0.01-0.2% S, 1.0-3.5% Cr, 0.1-0.5% V, 0.001-0.02% Al, 0.0005-0.02% Ca, 0.0005-0.01% O, and the remainder being Fe and unavoidable impurities. Here, the contents of Cr and V satisfy the formula: ([Cr]+1.97×[V])≥2.15 (wherein values inside [ ] represent the contents of the components shown in percentages). Here, sulfides comprising MnS and CaS and hard oxides are dispersed in a matrix. The percentage of CaO against the total amount of hard oxides, the percentage of Ca against the total amount of sulfides and the area occupied by sulfides in the steel product are specified. COPYRIGHT: (C)2003,JPO
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