What is the difference between hot dip galvanizing and cold galvanizing

Hot galvanizing is also called hot dip zinc and hot dip galvanizing is an effective way of metal corrosion resistance, mainly used for metal structure industry facilities, is after cleaning of steel in above 500 ℃ high temperature melting liquid zinc, zinc layer adhered on the surface of the steel members, which have the purpose of corrosion protection.

Cold galvanizing, also called electricity galvanized, is the use of electrolytic equipment put pipe after degreasing, pickling in composition of zinc salt in the solution, and connect the cathode electrolytic equipment, across the tube placed zinco, connected to the anode electrolytic equipment, power supply is connected using current from the positive to the negative directional moving deposits a layer of zinc on the pipe fittings, cold is plated fittings galvanized after processing. Cold galvanizing coatings are mainly antiseptic by electrochemical principle. Therefore, it is necessary to ensure sufficient contact between zinc powder and steel to generate electrode potential difference. Therefore, surface treatment of steel is very important.

In a word, hot galvanizing and cold galvanizing chemistry principle are different, hot galvanizing belongs to electrochemical reaction. Cold galvanizing is a physical treatment, only a layer of zinc on the surface, so the zinc layer is easy to fall off. Hot galvanizing is often used in building construction. Its main purpose is not the same. Hot galvanizing is mainly used for equipment with large structure and large amount of zinc and thick coating. Cold galvanizing is mainly used for small parts with small size of structure, and less zinc is used at the same time, only a thin layer is needed.

In fact, it is easy to understand that hot galvanizing will not rust or be corroded in a few years, while cold galvanizing may be corroded in half a year, and the production cost of hot galvanized sheet is lower and the application scope is wider, making hot dip galvanizing the main method of metal protection such as steel.