First of all, the difference of the process is:
Hot-dip galvanizing is to immerse the workpiece in a molten zinc solution for a certain period of time after degreasing, pickling, dipping and drying.
Cold galvanizing is also called electro-galvanizing. It uses electrolytic equipment to degrease and pickle the workpiece into a solution containing zinc salt, and connects to the negative electrode of the electrolytic equipment. The positive electrode, connected to the power source, uses current to move from the positive electrode to the negative electrode, and a layer of zinc is deposited on the workpiece.
The difference in appearance: the appearance of electro-galvanized zinc is relatively smooth and bright, and the electro-plated layer adopting the color passivation process is also yellow-green as the main color, showing colorful. The plating layer using the white passivation process is bluish white or white to green light, and the plating layer of the white passivation process is slightly colorful at a certain angle from the sunlight. At the corners of complex workpieces, it is easy to produce "electric burning" and become gray, and the zinc layer in this part is thick. It is easy to form a current dead corner at the negative corner and produce an undercurrent gray area, where the zinc layer is thin. The whole workpiece is free of zinc tumors and agglomeration. The appearance of hot-dip galvanized steel is slightly rougher than that of electro-galvanized zinc, and it is silvery white. However, the zinc layer of hot-dip galvanizing is several tens of times thicker than that of electro-galvanizing, and its corrosion resistance is dozens of times that of electro-galvanizing.
The difference between galvanized finished products:
1. The inner and outer walls of hot-dip galvanized steel pipes are galvanized, while the cold-dip galvanized steel pipes are only galvanized on the outer walls;
2. The cold coating is uniform and the thickness is very thin; the hot coating is thick and the thickness is uneven.
3. The appearance of cold plating is bright, and the color of hot plating is dark.
4. Because the cold coating is thinner, the corrosion resistance is poor; the hot coating is tens of times that of the cold galvanizing because it is thicker, and it forms an infiltration layer with the base metal, which has good corrosion resistance.
5. The cold-galvanized steel pipe looks brighter, smooth and smooth; the appearance of hot-galvanized steel does not have the delicate and bright light of cold-galvanized steel. .
