Galvanized sheet types and characteristics in detail

(1) Surface state: galvanized sheet due to the coating process in the treatment of different ways, the surface state is also different, such as ordinary zinc flower, fine zinc flower, flat zinc flower, no zinc flower, and phosphate treatment of the surface and so on. The German standard also provides for the surface level.

(2) galvanized sheet should have a good appearance, there shall be no harmful defects on the use of the product, such as no plating, holes, rupture, and slag, more than the thickness of the plating, abrasion, chromic acid stains, white rust and so on. Foreign standards on the specific appearance of defects are not very clear. When ordering some specific defects should be listed in the contract.

1, the amount of galvanization is expressed in galvanized sheet zinc layer thickness of a commonly used and effective method. Galvanized steel is generally 180-220g / ㎡, in the humid southern region can increase the amount of galvanized to 275g / ㎡ to improve the service life of steel components.

The service life of galvanized products is generally 20-25 years.

2, galvanized steel strip zinc layer characteristics. Electro galvanized zinc layer is not able to form zinc flower, hot-dip galvanized layer has zinc flower, the formation process is as follows: when the galvanized strip from the zinc pot out of the air knife blowing, a large number of zinc liquid was blown back to the zinc pot, when the strip steel surface there is a pure layer of zinc, liquid attached to the surface of the steel plate, the formation of a large number of crystalline nuclei in the surface of the steel plate, with the rise of the steel plate cooling, so that the crystalline nuclei slowly grow into the zinc flower. The faster the cooling rate of zinc flower the smaller, the slower the cooling rate of zinc flower the larger.

3, no flower galvanized sheet: in fact, the zinc flower is only ornamental value, no practical use value, on the contrary, in the corrosion prevention is not good, in developed countries are the implementation of small zinc flower and no zinc flower galvanized steel.