Method for manufacturing spheroidal graphite cast iron, cast articles made of spheroidal graphite cast iron, structural parts for automobiles, and cast articles made of spheroidal graphite cast iron.

摘要

A spheroidal graphite cast iron meeting N (5-) ‰¥ 250, N( 5-20 )/N (5-) ‰¥ 0.6, and N (30-) /N (5-) ‰¤ 0.2, wherein N (5-) represents the number (/mm 2 ) of graphite particles having equivalent-circle diameters of 5 µm or more, N (5-20) represents the number (/mm 2 ) of graphite particles having equivalent-circle diameters of 5 µm or more and less than 20 µm, and N (30-) represents the number (/mm 2 ) of graphite particles having equivalent-circle diameters of 30 µm or more, among graphite particles observed in an arbitrary cross section of at least 1 mm 2 .