The main difference between hot-dip galvanizing and cold-dip galvanizing of hexagonal bolts lies in the galvanizing process, thickness, corrosion resistance and applicable occasions. The following is a detailed explanation of the differences between the two galvanizing methods:
1. Galvanizing process:
Hot-dip galvanizing:Hot-dip galvanizing is to immerse the hexagonal bolts in high-temperature molten zinc liquid. The zinc reacts chemically with the steel surface to form an alloy layer, which usually has a very obvious silver-white metallic luster. Hot-dip galvanizing usually forms a thicker zinc layer on the surface of the bolt, with a thickness of generally more than 50μm. The specific thickness depends on the use environment and the required corrosion resistance.
Cold galvanizing (electrogalvanizing):Cold galvanizing is to deposit zinc on the surface of the hexagonal bolt through the electroplating process. The electroplating process is to reduce zinc ions to the surface of the bolt through an electric current in an electrolytic cell to form a thin zinc coating, usually between 5μm and 15μm thick. Cold galvanizing is usually thinner than hot-dip galvanizing and has a relatively smooth surface.
2. Zinc layer thickness:
Hot-dip galvanizing:The zinc layer of hot-dip galvanizing is thicker, usually up to 50μm or more. The thicker zinc layer makes it more corrosion-resistant and wear-resistant in more harsh environments.
Cold-dip galvanizing:The zinc layer of cold-dip galvanizing is thinner, usually between 5μm and 15μm, so its corrosion resistance is poor and it is suitable for occasions with low corrosion resistance requirements.
3. Corrosion resistance:
Hot-dip galvanizing:Due to the thick zinc layer, hot-dip galvanized bolts have stronger corrosion resistance and can effectively resist corrosion from moisture, salt and chemicals in the air. Therefore, hot-dip galvanizing is usually used outdoors, in marine environments or other harsh environments.
Cold-dip galvanizing:Due to the thin zinc layer, the corrosion resistance of cold-dip galvanizing is relatively weak, and it is suitable for occasions where the corrosion environment is not serious, such as indoor environments or less demanding anti-corrosion applications.
4. Appearance:
Hot-dip galvanizing:The surface of hot-dip galvanizing usually presents a rougher appearance, the zinc layer is not as smooth as cold-dip galvanizing, and there may be zinc flowers (white crystal points) or uneven zinc layer. Although the appearance of hot-dip galvanized bolts is relatively rough, their anti-corrosion performance is far better than cold-dip galvanizing.
Cold-dip galvanizing:The surface of cold-dip galvanizing is relatively smooth, the color is uniform, the gloss is strong, and the appearance is more exquisite. Because the cold-dip galvanizing layer is thinner, the appearance is smoother and more delicate.
5. Cost:
Hot-dip galvanizing:Due to the complex process of hot-dip galvanizing, involving high-temperature zinc liquid, long processing time, etc., its cost is usually higher than cold-dip galvanizing.
Cold-dip galvanizing:The cost of cold-dip galvanizing is relatively low, because the electroplating process is relatively simple, suitable for large-scale production and lower cost requirements.
6. Applicable occasions:
Hot-dip galvanizing:Applicable to occasions that require higher corrosion resistance, such as bridges, steel structures, petrochemical equipment, outdoor mechanical equipment, etc.
Cold-dip galvanizing:Applicable to occasions with lower anti-corrosion requirements, such as indoor equipment, some mechanical equipment and light industrial use.
In general, hot-dip galvanizing is suitable for occasions with higher requirements for corrosion resistance, while cold-dip galvanizing is suitable for occasions with higher requirements for appearance but less stringent requirements for corrosion resistance.
Post time: Dec-26-2024