Ductile iron (DI) pipes are used for water and sewage transportation. Ductile iron pipe has long been the standard material for conveying water and sewage in municipal, utility and industrial piping systems.Ductile iron pipe, a product of advanced metallurgy, offers unique properties for conveying water under pressure, and other piping uses. It combines the physical strength of mild steel with the long life of gray cast iron. In addition to the benefits of long life, corrosion resistance, high structural strength, and tight joints, ductile iron is also readily machinable, an important requirement in any pipe that must be drilled, tapped or cut.