| 摘要 |
PROBLEM TO BE SOLVED: To provide a spheroidal graphite cast iron superior in strength, elongation and machinability, which improves strength and elongation and can obtain adequate machinability, and to provide a production method therefor. SOLUTION: The spheroidal graphite cast iron includes the spheroidal graphite, a ferrite phase produced around the spheroidal graphite and a pearlite phase produced among adjacent ferrite phases. The pearlite phase mainly includes a granular pearlite and a lamella pearlite. The production method includes: pouring the molten spheroidal graphite cast iron into a mold; taking out the solidified spheroidal graphite cast iron from the mold; cooling the spheroidal graphite cast iron at such a cooling rate that the pearlite is produced; then heating and holding the spheroidal graphite cast iron to the temperature range right under or right above the A1 transformation point; and afterward, cooling the spheroidal graphite cast iron. COPYRIGHT: (C)2011,JPO&INPIT
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