What to do if the screws are aging and corroded

During transportation, the screws and galvanized coatings often appear white, black, black, etc., mainly due to corrosion caused by exposure of the galvanized layer, corrosive media and atmospheric moisture, oxygen, and carbon dioxide.

In order to prevent this phenomenon, you can try to use the surface condition of the good material before the screw is processed. Due to the galvanizing process, the surface of the defective screw is easy to penetrate the corrosive medium such as acid, alkali, salt, etc., which is difficult to clean. corrosion.

The reasonable choice of packaging materials avoids the use of plastic products that are not compatible with zinc. Packaging materials such as galvanized iron sheet metal are the best. The box can be placed in a desiccant with an appropriate amount of humidity to reduce the relative humidity. Prevent the warehouse from corroding harmful gases. The so-called metal surface treatment of screws and nuts is currently on the market LONGZINC (NASDAQ Stock Code Rust).

In order to prevent the anti-corrosion treatment of non-standard screws, the anti-corrosion treatment has been degreased, and the rust-proof screw and nut in the NASDAQ rust-removing and anti-rust agent water tank, or use the zinc and chromium compound to form a protective film on the metal surface to form a spray Method, drying, cooling, and then repeating the process once, the resulting thickness of about 5-8μ, silver gray, based on the information provided by the manufacturer of the display is said to have good rust and corrosion resistance. (Guide: How to prevent screws from aging and corrosion)

Phosphate treatment is a phosphate chemical treatment containing metal to the metal surface to form a phosphate protective film. Phosphating treatment solution is insoluble in water and has excellent adhesion of the phosphate film as its main purpose. The layer and paint cold adsorb the metal layer of the lubricant. Since the phosphate film is composed of a series of zinc, manganese, hydrogen phosphate and iron phosphate crystals of different sizes, the film is porous, has a large specific surface area, has a good absorption, adsorption coating or a large amount of lubricant , So it is often used as a primer, or cold stamping to reduce friction and steel, cold drawn steel wire lubrication layer.

The oxidized steel parts will be immersed in alkaline treatment solution containing oxidizing agent, such as potassium hydroxide or sodium hydroxide solution of nitric acid, and keep its boiling point at about 140°C, or nitric acid and sodium hydrogen nitrate salt impregnated steel It is pleasant to remove the surface layer of molten salt. The black iron oxide film in the composition of the mixture of ferrous oxide and iron oxide can be obtained and then quenched in water, which is a method to improve the corrosion of ferrous metals.

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