What are the requirements for corrosion resistance of galvanized steel pipes?

　　Although the use of ASTM A53 Hot Dipped Galvanized Steel Pipe is more and more extensive and the environment is different, the requirements for galvanized steel pipes are more and more stringent. Now there are new requirements for the rust resistance of galvanized steel pipes, because the requirements for painting process of galvanized steel pipes are also very stringent. Then, what methods will be used to improve the rust resistance of galvanized steel pipe in the factory?

　　1. Rust removal: This is an important process for galvanized steel pipes and components before coating. It is the key to the quality of galvanized steel pipes. Thorough rust removal can improve the adhesion of antirust paint and prolong the service life of galvanized steel pipe.

　　2. After sandblasting, shot blasting or pickling, the surface of galvanized steel pipe is cleaned up, such as iron oxide scale and rust, which improves the adhesion of the coating. When the installation site is unconditionally treated by sand blasting and shot blasting, manual mechanical rust removal can be used, but the quality grade of rust removal must be achieved.

　　3. When using sandblasting or manual mechanical rust removal, the surface metal of the galvanized steel pipe is directly exposed to the air because of the falling off of the oxide scale on the galvanized steel pipe. If a primer is not painted in time, the surface of the galvanized steel pipe is liable to rust again, which affects the adhesion of the paint film. Because paint is a kind of time-sensitive material, the stock backlog is easy to expire, so the main indexes must be checked before the paint is used, and the results meet the standard before it can be used.