Ductile Iron (DI) pipe is a type of cast iron pipe made from spheroidal graphite iron — a material that combines the traditional corrosion resistance of cast iron with dramatically improved mechanical properties including higher tensile strength, better ductility, and superior impact resistance compared to conventional grey cast iron.
Ductile Iron pipes are manufactured by the centrifugal casting process (also called spin casting or de Lavaud process). Molten spheroidal graphite iron is poured into a rotating cylindrical mold, and centrifugal force distributes the metal uniformly along the pipe wall, resulting in a dense, defect-free casting with consistent wall thickness.