Ductile iron, also known as ductile iron, is a special type of cast iron material that is usually made by adding a certain amount of elements such as magnesium and lead to the formation of spherical graphite during the casting process, improving the strength and toughness of the casting. It has the advantages of high strength, high toughness, good fatigue resistance, strong corrosion resistance, easy processing and heat treatment, and is widely used in the manufacturing of parts in fields such as machinery, automobiles and transportation, agricultural machinery, construction engineering, and power.

The reason why ductile iron castings have good corrosion resistance is mainly because the basic composition structure of ductile iron contains spherical graphite. There is a protective film between spherical graphite and the iron matrix, which can effectively prevent the corrosion of the corrosive medium. At the same time, spherical graphite has an adsorption effect, which can adsorb impurities in the corrosive medium and prevent the diffusion of the corrosive medium to the matrix. In addition, the surface treatment of ductile iron castings also plays a role in preventing corrosion. Common surface treatment methods include phosphating, oxidation, galvanizing, etc. These methods can form a protective film on the surface of ductile iron castings to prevent corrosion by corrosive media.