| 摘要 |
PROBLEM TO BE SOLVED: To increase the machinability and ductility of a graphite cast steel. SOLUTION: A graphite cast steel contg., by weight, 0.45 to 1.5% C, 1.0 to 5.5% Si and one or >= two kinds of 0.01 to 0.10% Mg, 0.002 to 0.02% Ca and 0.008 to 0.25% rare earth metals, and the balance Fe with inevitable impurities is subjected to controlled cooling in the temp. range of the eutectoid transformation temp.±30 deg.C at the average cooling rate of <=0.15 deg.C/S in casting.
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