Ductile iron pipes are a type of cast iron pipe. Quality requirements call for the spheroidizing grade of the cast iron pipe to be controlled at levels 1-3 (spheroidizing rate >80%), thus improving the mechanical properties of the material itself. The finished ductile iron pipes, with their iron essence and steel performance, exhibit good mechanical properties after annealing. They boast excellent corrosion resistance, good ductility, and excellent sealing performance. They are easy to install and are mainly used for municipal and industrial water supply, gas transmission, and oil transportation. The matrix contains a certain number of spherical graphite in the ferrite and pearlite, with the proportion of ferrite and pearlite in the matrix varying depending on the nominal diameter and requirements for elongation. For small diameters, the pearlite proportion is generally not more than 20%, while for large diameters, it is usually controlled around 25%.