This issue can be addressed by first understanding that metal surfaces often accumulate dust, oil, scale, rust, contaminants, salt, or loose old paint films. Among these, scale is a common but often overlooked component. Scale is a dense oxide layer formed during the high-temperature forging and shaping of steel, typically adhering firmly but being more brittle than the steel itself. As a cathode, it accelerates metal corrosion. Failing to remove these substances before painting will undoubtedly affect the adhesion and corrosion resistance of the entire coating. Statistics show that over 70% of paint issues are caused by improper surface treatment. Therefore, appropriate surface preparation is crucial for the performance of a metal corrosion protection painting system. With that said, we've gained some basic knowledge about metals. Now, let's discuss the materials used for water corrosion protection.
We typically use epoxy coal tar paint; for higher standards, we can opt for a 3-coat-2-fabric system. This involves three layers of paint and two layers of glass fiber fabric, applied in an alternating pattern. For general requirements, we simply use the epoxy coal tar primer and finish, applying each twice. It's simple and convenient, and this is usually the chosen approach.
Inspection of the internal steel pipe is necessary to determine if it is for drinking water. If so, it must be coated with environmentally friendly paint, such as epoxy polyamide paint.
