| 摘要 |
PROBLEM TO BE SOLVED: To provide an iron based casting which has excellent machinability, and is suitable as the stock for a quenching type cam shaft. SOLUTION: A flake graphite cast iron casting has a composition comprising, by mass, 0.05 to 0.12% S and 0.2 to 0.7% Cu, and preferably comprising 2.8 to 3.8% C, 1.5 to 2.5% Si, 0.5 to 1.0% Mn,≤0.3% P, 0.05 to 0.15% S and 0.2 to 0.6% Cu, and the balance Fe with inevitable impurities, and has structure where the base structure in the central part is mainly made up of a pearlitic phase, and the base structure in the surface layer part consists of a ferritic phase in 20 to 50% by area ratio, and the balance pearlitic phase. Thus, its machinability is improved, and preferably a cam shaft with prescribed shape and dimensions is easily obtained by working. COPYRIGHT: (C)2004,JPO&NCIPI
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