The screw is aging and corroded. What should be done in the process of screw processing?

The screws during shipping, zinc coating, often appear white, black, The phenomenon of black is mainly caused by the exposure of zinc coating and corrosive medium and atmospheric moisture, oxygen and carbon dioxide.

In order to prevent this phenomenon, you can try to use a good surface condition of the material before screw processing, due to galvanized Due to the process, the surface of the defective screw is easily penetrated by corrosive media such as acid, alkali, salt, etc., and it is difficult to clean and cause corrosion.

To a reasonable choice of packaging materials, avoiding the use of plastic products that are not related to zinc, packaging materials such as galvanized iron sheets Metal is fine, and can be placed in a suitable amount of humidity inside a desiccant to lower the relative humidity compatible to reduce and prevent harmful gases from corroding the warehouse.

In order to prevent non-standard screw anti-corrosion treatment, it has been degreased, and the water tank of rust remover and anti-rust agent in Nasdaq Anti-rust screw and nut dip, or use zinc and chromium compounds to form a protective film on the metal surface, form a spray method, and dry, cool, and then repeat the process once, the resulting about 5 ~ 8μ, silver-gray, based on The thickness of the information provided by the manufacturer of the display is said to have good rust and corrosion resistance.

Phosphating is a chemical treatment of phosphate containing metal to metal surfaces to form a phosphate protective film phosphating Treatment solution, insoluble in water, and has excellent adhesion of phosphate film, as its main purpose bottom layer and paint cold adsorption lubricant metal layer. Since the phosphate coating is composed of a series of crystals of zinc, manganese, hydrogen phosphate and iron phosphate of different sizes, the film is porous, has a large specific surface area, and 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 as a lubricating layer.

Oxidized steel parts will be dipped in a solution of potassium hydroxide or sodium hydroxide containing an oxidizing agent such as nitric acid Alkaline treatment liquid, and keep its boiling point at about 140°C, or nitric acid and sodium hydride nitrate impregnated steel molten salt, remove its surface layer is pleasant, to have a composition with a mixture of ferrous oxide and iron oxide The black iron oxide film can be quenched in water after quenching, which is a method to improve the corrosion of ferrous metals.