A preliminary investigation of strength models for degenerate graphite clusters in grey cast iron

Defects morphology primarily affects the mechanical properties of grey cast iron. In large castings, porosity and clusters of degenerate graphite are heterogeneously dispersed into the ferrous matrix and serve as initiation sites for fatigue and fracture processes. Strength and toughness of nodular cast iron compare to many grades of steel but experiments show that nodular cast iron also exhibits some specific effects, different from those typical of steels and due to cast iron microstructural inhomogeneity. In the present communication, we report on a preliminary investigation aimed at correlating the effect of the graphite microstructure to the mechanical properties of the material via a simplified geometrical description of the defects.