In 2026, ductile iron pipe has undoubtedly become the main force in underground pipeline renovation. This is no accident, but an inevitable result of the strong promotion of the national 15th Five-Year Plan and the upgrading of material technology.
Against the grand background of more than 5 trillion yuan investment in pipeline network renewal, ductile iron pipe, with its comprehensive properties of "long service life, high strength and toughness, and corrosion resistance", perfectly solves the long-standing problems of leakage in old pipe networks, and has leapt from an "alternative option" to a "must-choice" for municipal engineering.
At present, China's ductile iron pipe technology is in a leading position in the world. It has successfully overcome technical difficulties such as mass production of large-diameter pipes, and is widely used in major projects including the South-to-North Water Diversion and the Hanjiang-to-Weihe River Diversion. Meanwhile, such products have been successfully exported to more than 50 countries and regions in the Middle East, Southeast Asia, Africa, Europe and other places.
In the past, pipe material choices were diverse, but now national standards have given clear guidance.
15th Five-Year Plan (2026–2030): The state will invest over 5 trillion yuan in underground pipeline construction, clearly requiring the durability of pipes to be increased from 20 years to 50 years, and mandating the promotion of high-quality materials such as ductile iron pipes.
Mandatory indicators: Ministries and departments including the Ministry of Housing and Urban-Rural Development clearly require that ductile iron pipes should be preferred for water supply pipelines with a diameter of 100 mm and above. The target application ratio in municipal water supply networks is raised to over 65%. This means it is no longer an alternative but a must-choice in major projects.
Compared with brittle gray cast iron pipes or heavy concrete pipes, ductile iron pipe adopts a special spheroidization process to make graphite distribute spheroidally inside, thus combining the strength of steel and the toughness of cast iron. This unique microstructure endows it with extremely high tensile strength and elongation, enabling it to deform like rubber under stress without breaking. In complex working conditions such as foundation settlement, earthquakes or heavy vehicle rolling, it maintains the integrity of the pipeline system and greatly reduces the risk of pipe bursts. Meanwhile, its excellent sealing performance with flexible joints effectively solves the problem of easy leakage at traditional pipe joints, which is critical to reducing leakage rates in urban water supply networks.
In addition, the advancement of anti-corrosion technology enables ductile iron pipes to adapt to various extreme environments. For high-saline soil in coastal areas or acidic environments in industrial zones, special anti-corrosion coatings such as polyurethane and epoxy ceramic can be applied to effectively resist chemical erosion, extending the service life to 50 or even 100 years and greatly reducing life-cycle maintenance costs.
The fact that ductile iron pipe has become the main force essentially reflects the shift of urban governance from extensive to refined. With a service life of more than 50 years and an extremely low leakage rate, it meets the high standards of cities for the safety of lifeline projects.