What are the treatment methods for aging and corrosion of galvanized screws?

Galvanized screws made of carbon steel will inevitably age and corrode if used for a long time.
In the long-term use of galvanized screws and galvanized, white, black, black and other phenomena often appear, mainly due to corrosion caused by the galvanized layer, corrosive media, and exposure to water, oxygen, and carbon dioxide in the atmosphere.
In order to prevent this phenomenon, we can try to use good material surface condition before screw processing. Due to the galvanizing process, the defective screw surface is easily penetrated by acid, alkali, salt and other corrosive media, so it is difficult to clean and cause corrosion.
In order to prevent the anti-corrosion treatment of the galvanized screw from degreasing, and swimming on the anti-rust sand and the nut of the anti-rust agent on the Nasdaq, or use zinc and chromium compounds to form a protective film on it. The metal surface is formed by spraying method, then dried and cooled, and then the process is repeated once, you can get about 5-8 microns, so the galvanized screw has good rust and corrosion resistance.