Ductile iron pipes are fittings made by adding magnesium or rare earth magnesium combined with a spheroidizing agent to molten iron before pouring, which spheroidizes graphite, reduces stress concentration, and gives the pipe the advantages of high strength, high elongation, impact resistance, corrosion resistance, and good sealing; The inner wall adoptscement mortarLining improves the water transmission environment of pipelines, enhances water supply capacity, and reduces energy consumption; The pipe mouth adopts a flexible interface, and the pipe itself has a large elongation, which makes the pipeline flexible. It can work together with the surrounding soil in buried pipelines, improve the stress state of the pipeline, and thus enhance the reliability of pipeline operation. Therefore, China's water supply industry usually uses ductile iron pipes as the main pipe fittings.