| Common quality defects of galvanized sheet | ||
| Defect name | Defect performance | Cause |
| Galvanized peeling | Dezincification | Poor furnace temperature, improper substrate processing, etc. |
| Not galvanized | Part of the steel plate surface is not galvanized | poor raw materials, poor pre-treatment degreasing, poor furnace temperature |
| Bad spangle | Uneven spangle size, no spangle | Poor heating in the furnace area and poor cooling control |
| Zinc scar | Point and granular zinc dross attached to the surface of the steel plate | The scum or bottom dross in the zinc pot adheres to the steel belt |
| Oxidation | White rust | During storage, it absorbs moisture in the air and oxidizes. |
| 2Zn+O2 → 2ZnO | ||
| 5ZnO+2CO2+3H2O | ||
| →2ZnCO3·3Zn(OH)2 | ||
| Dark Spot | Black dots, blocky spots | Impurity precipitation reacts with moisture and carbon dioxide in the atmosphere, or friction during transportation. |
| Wave | Wavy edges or middle | Poor raw material or poor working condition of the pull-straightening roller. |
| Jagged edge | Jagged edges | When the raw material is cold rolled, the edges are uneven and jagged. |
| Uneven surface | Dent | Pits in the raw material or adhesion of foreign matter on the surface of the roller |
1.Choose a ventilated place in the house to avoid dew erosion or moisture penetration;
2.Make sure that the packaging paper is not damaged during storage;
3.Shorten the storage time as much as possible and protect its surface before corrosion;
4.If the plate is subjected to abnormal external pressure, the zinc layer will partly fall off;
5.Prevent dirt and oil powder from sticking to the surface, which will affect the galvanizing effect;
6.Skids or support frames should be added under the steel coils, and the number of stacked layers should not exceed two;
7.The rain cloth should be covered during transportation, and it must be cushioned with skids and rubber, and fixed with ropes.
Hot Dipped Galvanised Sheet
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