Galvanized steel plate refers to a steel plate plated with a zinc layer of a certain thickness to improve corrosion resistance. Since the 1970s, car body steel plates have used bonded zinc thin steel plates. During assembly, the forged zinc surface is placed on the inside of the car to improve the corrosion resistance of the car body, and the non-galvanized surface is placed on the outside of the car and sprayed with paint.
As automobiles' requirements for corrosion resistance continue to increase, the weight of galvanized steel sheets continues to increase, and double-layer galvanized steel sheets also appear. However, increasing the weight of galvanizing will also significantly increase the power consumption of electro-galvanizing, leading to an increase in material costs. Therefore, in the late 1970s, a type of galvanized steel sheet produced using the hot-dip galvanizing process appeared, called hot-dip galvanizing. Galvanized steel. Nowadays, galvanized steel sheets have been widely used in cars. The thickness of the galvanized steel sheets used is 0.5-3.0mm. Among them, the body panels are mostly made of 0.6-0.8mm thick galvanized steel sheets.
1) Surface condition: Due to different treatment methods in the coating process, the surface conditions of galvanized sheets are also different, such as ordinary zinc flowers, fine zinc flowers, flat zinc flowers, no zinc flowers, and phosphated surfaces, etc. German standards also specify surface levels.
(2) Galvanized sheets should have good appearance and should not have defects that are harmful to product use, such as no plating, holes, cracks and dross, excessive plating thickness, scratches, chromic acid dirt, white rust, etc.
1. The amount of galvanizing is a commonly used and effective method to express the thickness of the zinc layer of galvanized sheets. The galvanizing amount of steel plates is generally 180-220g/㎡. In humid southern areas, the galvanizing amount can be increased to 275g/m2 to increase the service life of steel components.
The service life of galvanized products is generally 20-25 years.
2. Zinc layer characteristics of galvanized strip steel. The electro-galvanized layer cannot form zinc flowers, but the hot-dip galvanized layer has zinc flowers. The formation process is 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 a liquid state, forming a large number of crystallization nuclei on the surface of the steel plate. 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.
3. Flower-free 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 zinc-free galvanized steel sheets are implemented.
Galvanized Sheet Specifications Table
| Quality | Material-No. | Standard | Available coatings |
|---|---|---|---|
| DX51D | 1.0917 (old 1.0226) | DIN EN 10346 (old 10327) | +Z, +ZF, +ZA, +ZM, +AZ, +AS |
| DX52D | 1.0918 (old 1.0350) | DIN EN 10346 (old 10327) | +Z, +ZF, +ZA, +ZM, +AZ, +AS |
| DX53D | 1.0951 (old 1.0355) | DIN EN 10346 (old 10327) | +Z, +ZF, +ZA, +ZM, +AZ, +AS |
| DX54D | 1.0952 (old 1.0306) | DIN EN 10346 (old 10327) | +Z, +ZF, +ZA, +ZM, +AZ, +AS |
| DX55D | 1.0962 (old 1.0309) | DIN EN 10346 (old 10327) | +AS |
| DX56D | 1.0963 (old 1.0322) | DIN EN 10346 (old 10327) | +Z, +ZF, +ZA, +ZM, +AZ, +AS |
| DX57D | 1.0853 | DIN EN 10346 (old 10327) | +Z, +ZF, +ZA, +ZM, +AS |
