What are the materials of galvanized sheets?
Galvanized sheet refers to a steel sheet coated with a layer of zinc on the surface. Galvanizing is an economical and effective anti-corrosion method that is often used. About half of the total zinc output is used in this process.
Galvanized sheet material:
①Hot-dip galvanized steel plate. The thin steel plate is immersed in a molten zinc bath, so that a layer of zinc adheres to the surface of the thin steel plate. At present, the continuous galvanizing process is mainly used for production, that is, the rolled steel plates are continuously immersed in a plating bath containing molten zinc to make galvanized steel plates;
②Alloyed galvanized steel sheet. This kind of steel plate also uses the hot dip method, but it is heated to about 500°C immediately after coming out of the tank, so that it forms an alloy film of zinc and iron. This kind of galvanized sheet has good paint adhesion and weldability;
③Electro-galvanized steel plate. This kind of galvanized steel plate has good performance by electroplating method. However, the coating is thin and its corrosion resistance is not as good as that of hot-dip galvanized sheets;
④ Single-sided galvanized steel plate and double-sided galvanized steel plate. Single-sided galvanized steel sheet is a product that is galvanized on only one side. In terms of welding, painting, anti-rust treatment, etc., it has better adaptability than double-sided galvanized sheets. In order to overcome the shortcomings of one side not being coated with zinc, there is another galvanized sheet that is coated with a thin layer of zinc on the other side.
Galvanizing amount The galvanizing amount of steel plates is generally 180-220g/m'. In humid southern areas, the galvanizing amount can be increased accordingly to 275g/m' to increase the service life of steel components. The service life of galvanized products is generally 20-25 years.
Characteristics of the zinc layer of galvanized strip steel: The electroplated zinc layer cannot form zinc spatter, while the hot-dip galvanized layer has zinc spatter. The formation process
As follows: When the galvanized strip comes out of the zinc pot, a large amount of zinc liquid is blown back to the zinc pot by the air knife. At this time, there is still a pure zinc layer on the surface of the strip, which is attached to the surface of the steel plate in liquid form and forms on the surface of the steel plate. A large number of crystallization nuclei, as the steel plate rises and cools, the crystallization nuclei slowly grow into zinc flowers. The faster the cooling rate, the smaller the spangles, and the slower the cooling rate, the larger the splatters.
Flowerless galvanized sheet:
In fact, zinc flowers only have ornamental value and have no actual use value. On the contrary, they are not good at anti-corrosion. In developed countries, small zinc flowers and no zinc flowers are used for galvanized steel sheets.
