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2023.01.28

The difference between hot galvanizing and cold galvanizing

hot galvanizing

1. Different concepts

Hot-dip galvanizing is also called hot-dip galvanizing and hot-dip galvanizing. It is an effective metal anti-corrosion method and is mainly used in metal structure facilities in various industries. It is to immerse the rust-removed steel parts in the molten zinc at about 500 ℃ so that the surface of the steel parts will be attached with a zinc layer, so as to achieve the purpose of anti-corrosion.

Electro galvanizing, also known as cold galvanizing in the industry, is the process of forming a uniform, dense, well-bonded metal or alloy deposition layer on the surface of the workpiece by electrolysis. Compared with other metals, zinc is a relatively cheap and easy-to-plate metal. It is a low-value anti-corrosion coating and is widely used to protect steel parts, especially to prevent atmospheric corrosion, and for decoration.

2. The process is different

Hot-dip galvanizing process: pickling of finished products – water washing – adding auxiliary plating solution – drying – rack plating – cooling – chemical treatment – cleaning – polishing – hot-dip galvanizing is completed.

Electro galvanizing process flow: chemical degreasing – hot water washing – water washing – electrolytic degreasing – hot water washing – water washing – strong corrosion – water washing – electro galvanized iron alloy – water washing – water washing – light emitting – passivation – water washing – drying.

3. The process is different

There are many processing techniques for hot-dip galvanizing. After the workpiece is degreased, pickled, soaked in medicine, dried, and other processes, it can be immersed in the molten zinc liquid pool. After a certain period of time, it can be removed. Some hot-dip pipe fittings are processed in this way.

Electrolytic galvanizing is processed by electrolytic equipment. After degreasing, pickling and other processes, it is immersed in a solution containing zinc salts, and connected to electrolytic equipment. A zinc layer is deposited on the workpiece during the directional movement of the positive and negative electrodes.

4. The appearance is different

The overall appearance of hot-dip galvanizing is a little rough, and there will be watermarks, dripping tumors, etc., especially at one end of the workpiece, which is silver-white. The surface layer of electro-galvanized is relatively smooth, mainly yellow-green, of course, there are also colorful, bluish-white, white with green light, etc. The whole workpiece basically does not appear to have zinc tumors, agglomerations, etc.