SPHERICAL GRAPHITE CAST IRON, CAST ARTICLE AND AUTOMOBILE STRUCTURAL COMPONENT COMPRISING SAME, AND METHOD FOR MANUFACTURING CAST ARTICLE COMPRISING SPHERICAL GRAPHITE CAST IRON

摘要

A spherical graphite cast iron characterized by satisfying the expressions N_(5-) ≥ 250, N_(5-20)/N_(5-) ≥ 0.6, and N_(30-)/N_(5-) ≤ 0.2, where N_(5-) (particles/mm²) is the number of graphite particles having an equivalent circle diameter of 5 µm or greater, N_(5-20) (particles/mm²) is the number of graphite particles having an equivalent circle diameter of 5 µm to less than 20 µm, and N_(30-) (particles/mm²) is the number of graphite particles having an equivalent circle diameter of 30 µm or greater among graphite particles observed in an arbitrary cross section (in at least 1 mm²).