Nodular cast iron pipe is the product of modern city water supply, property fire control and natural gas transportation. In order to solve its corrosion problem, many attempts have been made to find a kind of anticorrosive material with low price and good quality, which can be applied to nodular cast iron pipe, that is zinc.
The zinc spraying ;layer of nodular cast iron pipe can pass through the electrochemical effect of zinc and iron, so as to effectively protect the pipe and form a stable protection. In the process of touching the soil, The metal zinc on the surface of the ductile iron pipe will gradually turn into a tight, adherent and continuous zinc salt layer. In addition, the zinc spraying layer also has a great advantage, that is, it can repair the damage, because the zinc ions migrate to the damage through the sealing pores to repair the damage and turn into a stable insoluble spray.
In addition to zinc coating, there are many ways of anti-corrosion treatment, such as asphalt paint coating, but it is mainly used to transport gas pipes. Preheating the pipes before painting can improve the adhesion of asphalt paint and accelerate the drying.
Epoxy coal tar pitch coating is suitable for both gas pipeline and sewage pipeline, because it is a two-component coating with high adhesion and very lubricating appearance.
In addition, epoxy ceramic lining can also be used for anticorrosion of ductile iron pipes, although it has high adhesion and finish, and is an excellent anticorrosive coating.
However, due to the difficulty of production technology and high cost, there are certain limitations in the use.