| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a surface-modified steel having a thick modified layer with a thickness of >1 mm which is free from defects in the surface part and in which carbon and silicon are enriched, and to provide a precise casting method which can obtain cast iron and a cast steel product having the modified layer and having excellent dimensional precision. Ž<P>SOLUTION: There is provided the surface modified steel, wherein the base part has a composition comprising, by mass, ≤3.9% C, ≤3.1% Si, ≤2.5% Mn, ≤0.8% P and ≤0.15% S, and the balance iron (Fe) with inevitable impurities, and the composition of the surface part is enriched in C: higher than the C% of the base part to 5.0%, and Si: higher than the Si% of the base part to 6.0%. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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