Gray iron is one of the pig iron, also known as cast iron. Carbon content of about 3%, the content about 2% silicon. Cross section is dark gray, usually called gray iron.
The carbon in the iron alloy is flake graphite morphology. Qualitative soft, cutting processing can be performed. Easy to flow when hot, casting performance is good. More wear-resisting. Strength and ductility. Because the graphite soft and lubrication, so this kind of pig iron has good cutting, wear-resisting and casting performance, etc. But, because of the existence of flake graphite, lowered its tensile strength, which it cannot be forged, can only be used in the manufacture of all kinds of castings, such as casting machine tool bed, iron pipe, etc. See water easy to rust. Casting is easy to produce porosity.
Gray iron, carbon content is higher (2.7% ~ 4.0%), carbon mainly