Compared with gray cast iron, nodular cast iron has an absolute advantage in strength. The tensile strength of nodular cast iron(Ductile Cast Iron Castings) is 60K, while the tensile strength of gray cast iron is only 31k. The yield strength of ductile iron is 40k, but gray cast iron does not show yield strength, and eventually rupture. The strength and cost ratio of nodular cast iron is much better than that of grey cast iron. Nodular graphite cast iron is the same as gray cast iron in the field of corrosion resistance.