Ductile iron pipes are products used in modern urban water supply, property fire protection, and natural gas transportation. Many attempts have been made to solve their corrosion problems, and a cost-effective and suitable anti-corrosion material for ductile iron pipes has been found, which is zinc.
The zinc spray layer of ductile iron pipes can undergo the electrochemical effect of zinc and iron, thereby providing effective protection for the pipeline and forming a stable protective effect. During the process of touching the soil, the metallic zinc on the surface of ductile iron pipes will gradually transform into a tight, adhesive, and contiguous zinc salt layer. In addition, this zinc spray layer has a major advantage as it can repair the damaged area, as zinc ions migrate to the damaged area through sealed pores to supplement the wound and become a stable and insoluble spray material.
In addition to using zinc coating as a anti-corrosion measure for ductile iron pipes, there are many other anti-corrosion treatment methods, such as asphalt paint coating. However, it is mainly used for transporting gas pipelines. Preheating the pipes before painting can improve the adhesion of asphalt paint and accelerate drying.
Alternatively, it can be a cement mortar lining and a special coating, which is an internal anti-corrosion method suitable for pipelines transporting sewage and can improve the corrosion resistance of the lining; Epoxy coal tar coating is suitable for both gas and sewage pipelines, as it is a two-component coating with high adhesion and a very lubricating surface.
In addition, epoxy ceramic lining can also be used for anti-corrosion of ductile iron pipes, although it has high adhesion and smoothness, making it an excellent anti-corrosion coating. However, due to the difficulty of production technology and high cost, there are certain limitations in its application.