The difference between hot-dip galvanizing and cold-dip galvanizing

First, the difference between hot-dip galvanizing and cold-dip galvanizing

1. The thickness is different

The hot-dip galvanized zinc layer itself is relatively thick, generally more than 10um thick, so it has a good anti-corrosion ability, although the surface is bright, but slightly rough, and there may be zinc flowers. The electro-galvanized zinc layer is very thin, only about 3-5um thickness, although the surface is smooth, but there will be gray, dirty, good processing performance, insufficient corrosion resistance.

2. The output is different

Hot-dip galvanizing is mass-produced, so it has a good output. Electrogalvanizing can not be produced in large quantities, so its output is relatively low.

3. The price is different

The effect, processing performance, and adhesion of the electrogalvanized surface are not out, and the price will be more expensive than hot-dip galvanizing, and the cost of electrogalvanizing itself is higher, and its price is high.

4. The plating structure is different

The surface of hot-dip galvanized is a pure zinc coating, the coating is uniform and non-porous, but there will be a layer of relatively brittle compounds between the coating and the matrix. The electrogalvanized coating is only composed of zinc atoms, which is the zinc atoms deposited on the surface of the steel strip, which belongs to the physical attachment effect, and there are many holes on the surface, so it is easier to be corroded.

Second, they can be distinguished from several aspects

1. Distinguish from the process

There are many processing techniques for hot-dip galvanizing, and it is necessary to immerse in the molten zinc liquid pool after the workpiece degreasing process, pickling, impregnation, drying and other processes, and immerse it for a certain period of time to put it forward, so that it is hot-dip galvanizing, like some hot-dip pipe fittings are processed in this way. Cold galvanizing is actually electrogalvanizing, using electrolysis equipment to process, to go through degreasing, pickling and other processes after immersion in a solution with zinc salt components, connect electrolysis equipment, in the positive and negative electrode current directional movement of the workpiece precipitated zinc layer precipitated. 

2. Distinguish from appearance

The overall appearance of hot-dip galvanizing is slightly rougher, which will produce process water lines, dripping tumors and other performances, especially the performance of one end of the workpiece is obvious, and the whole is silvery-white. The surface of electrogalvanized is relatively smooth, mainly yellow-green, of course, there are colorful, cyan-white, white green light and other performance, the entire workpiece basically does not appear zinc tumor, agglomeration and other phenomena.