What is the difference with ordinary gray iron castings of ductile casting?

Nodular cast iron and cast iron (Hui Zhutie). Has certainadvantages of ductile iron strength. Resistance of castingtensile strength of ductile iron is 60K and the tensile strength of cast iron is only 31k of ductile iron casting yieldstrong degree is 40K and the iron did not show a yield strength, and the ending of cracking. The strength of the ductile iron -- the interest is far better than cast iron.Nodular cast iron in corrosion resistance of ductile cast ironand cast iron.