Ductile iron pipe refers to the pipe which is cast by centrifugal ductile iron machine at high speed after adding nodulizer into the molten iron with the size greater than 18, and is referred to as ball pipe, ductile iron pipe and ductile cast pipe for short. Mainly used for conveying tap water, it is an ideal choice for tap water pipeline. The essence of cast iron steel pipe is ductile iron pipe. Ductile iron pipe is called this because it has the properties of iron and steel. The graphite in nodular cast iron pipe exists in spherical shape, and the size of graphite is generally 6-7. In terms of quality, the spheroidization grade of cast iron pipe is required to be controlled at 1-3 grade, and the spheroidization rate is greater than or equal to 80%. Therefore, the mechanical properties of the material itself have been better improved, and it has the nature of iron and the properties of steel. After annealing, the metallographic structure of ductile iron pipe is ferrite and a little pearlite, which has good mechanical properties, so it is called cast iron pipe. Features: It has the properties of iron, excellent properties of steel, excellent corrosion resistance, good ductility and simple installation, and is mainly used for water supply and gas transmission in municipal industrial and mining enterprises.