The nodular cast irons are characterized by high mechanical properties compared to cast iron with lamellar graphite or vermicular graphite. The ductile iron has already been the subject of many studies especially since the literature is rich on them, and sources of information are different. The fact is that the mechanical properties of nodular cast iron (FGS) depend on the number of graphite grains, their roundness, the solidification rate and nature of the matrix [3]. Many studies of nodular cast irons showed that the more spherical particles of graphite, the higher the mechanical properties are high. In gray cast irons, the graphite spheroids have anticracking and give the ductile iron ductility. Note in this connection that the higher the number of graphite grains, the higher the ductile iron has better mechanical properties. In cast iron, the nature of the matrix is depending on several parameters including the cooling rate of molten metal, the thickness, shape and dimensions of parts. The faster cooling is slow over rate of ferrite is important [3, 4]. In this paper, we tested three types of sand casting: sand –based sodium silicate, furan resin and green sand on samples spherical graphite cast iron of different thickness. The objective in this article is to determine the number of grains of graphite and ferrite for each type of sand casting under the same experimental conditions including the cooling rate and chemical composition of the liquid metal.