Sometimes, we find that during the transportation proce […]
Sometimes, we find that during the transportation process, we find that zinc coatings on screws often appear white, black, and black. In fact, this is a corrosion phenomenon. In this case, we need to deal with it in time. Avoid more serious situations. Perhaps many people do not know that these conditions will occur in screws, so it is important to understand clearly, so let's understand how the screws age.
In order to prevent the anti-corrosion treatment of non-standard screws, it is already degreased, and the Nasdaq rust and antirust agent water tank rustproof screw nut swims freely, or the zinc and chromium compounds are used to form a protective film on the metal surface, forming a spray method, Drying, cooling, and then repeating the process once, the obtained thickness of about 5 to 8 μ, silver gray, based on the information provided by the manufacturer of the display, is said to have good rust and corrosion resistance.
Phosphate treatment is a chemical treatment of phosphate containing metal to metal surface to form a phosphate protective film. Phosphating treatment solution is insoluble in water and has excellent adhesion of phosphate film as its main purpose. Bottom layer and coating Cold-adsorbed lubricant metal layer. Since the phosphate coating is composed of a series of different sizes of zinc, manganese, hydrogen phosphate and iron phosphate crystals, the film is porous, has a large specific surface area, has a good absorption, an adsorbed coating or a large amount of lubricant It is often used as a primer, or cold stamping to reduce friction and lubricating layers of steel and cold drawn steel wires.
The oxidized steel parts will be immersed in an alkali treatment solution containing an oxidant such as potassium hydroxide or sodium hydroxide solution of nitric acid, and keep its boiling point at about 140 ° C, or nitrate and sodium hydrogen nitrate impregnate the molten salt of the steel It is pleasant to remove the surface layer, and the eyes with the black iron oxide film in the composition having a mixture of ferrous oxide and iron oxide can be quenched in water after being obtained, which is a method to improve the corrosion of ferrous metals.