Cast iron drainage pipes are required to have a spheroidizing grade of 1-3 (spheroidizing rate > 80%), thereby significantly improving the material's mechanical properties, combining the essence of iron with the performance of steel. After annealing, the spheroidal cast iron pipes have a microstructure of ferrite with a small amount of spheroidite, offering excellent mechanical and corrosion-resistant properties, good ductility, and superior sealing performance. They are easy to install and are mainly used for municipal, industrial, and mining enterprises for water supply, gas transmission, and oil transportation.