For example, in gray iron, its carbon exists in iron ore in the form of graphite, the crack is often gray, soft and tough, simple filter cutting, suitable for casting. In the white iron, the carbon and iron are combined to form iron carbide, the crack appears white, the quality is very strong and brittle, and it is the material of malleable steel. Alloying grade is composed of various alloying elements with different composition and structure.
Zinc is a silver-white metal, brittle at room temperature, soluble in acid and alkali, known as amphoteric metal. Pure zinc is more stable in dry air, and small in humid air or water containing carbon dioxide and oxygen. A thin film layer of basic zinc carbonate will be formed on the surface, which can delay the corrosion rate of zinc layer. The corrosion resistance of galvanized layer in aqueous solution of acid, alkali and sodium chloride is relatively strong. It is also not resistant to corrosion in atmospheres containing carbon dioxide and hydrogen sulfide and in Marine atmospheres; In high temperature and high humidity air and containing organic acid atmosphere is small, galvanized layer is also easy to be corroded.
Temporary rust prevention is to prepare for the completion of the mission of the protective layer to be removed. The methods include: cajoling corrosion inhibitors, coating antirust oil, peeling molecular compound plastics, drying air, vacuuming, etc. Change the internal structure of the metal: new chromium, nickel and other alloy elements made of stainless steel, but the alloy is not much, expensive, difficult to produce widespread application.
The entire steel surface is protected, and the melted zinc is easily coated evenly, whether in the interior of the pipe fitting in a depression, or in any other corner where the coating is difficult to access. The hardness of galvanized coating is greater than that of steel. The Eta layer of the upper layer of Z is only 70 DPN hardness, so it is easy to be dented by collisions. However, the hardness values of the lower layer of Zeta layer and delta layer are 179 and 211 DPN respectively, which are higher than that of the iron material of 159 DPN. Therefore, its impact resistance and wear resistance are quite good.
Maintenance is indispensable in the use of galvanized wire. Large coils of galvanized silk should be coated with oil, fiber core immersion oil, oil is required to protect the fiber core is not rotten, not rust, wire moisture fiber, and from the internal lubrication wire rope. Surface coating so that all wire rope strands in the surface, are evenly coated with a layer of rust-proof lubrication grease, which for friction lifting and mineral water large mine rope, to be coated with grinding and water-resistant black oil grease. Coated with red oil with strong film and good rust resistance, it is required to have a thin oil layer, which is easy to keep clean during operation.