Electrogalvanizing, commonly known as cold galvanizing, is an electrochemical method. The zinc ingot is used as the anode. After the zinc atom loses electrons, it becomes an ionic state and dissolves into the electrolyte. The steel strip is used as the cathode. Zinc atoms are deposited on the surface of the steel strip, forming a coating.

There is a big difference in the amount of galvanizing between hot-dip galvanized sheet and electro-galvanized sheet. The galvanizing amount of hot-dip galvanizing cannot be too small, generally the minimum is 50-60g/m2 on both sides, and the maximum can reach 600g/m2. The galvanized layer of the electro-galvanized sheet can be very thin, the minimum is 15g/m2, but if the coating is thicker, the production line speed is very slow, which is not suitable for the technological characteristics of modern units, generally the maximum is about 100g/m2. Because of this, the production of electro-galvanized sheet is greatly restricted.

Hot-dip galvanized sheet and electro-galvanized sheet are fundamentally different in the structure of the coating. There is a slightly brittle compound layer between the pure zinc coating of the hot-dip galvanized sheet and the steel strip substrate. When the pure zinc coating is crystallized, most of the zinc flowers are formed, and the coating is uniform and free of pores. The zinc atoms of the electro-galvanized layer are only deposited and precipitated on the surface of the steel strip, and are attached to the surface of the steel strip by physical action. There are many holes to dry, and it is easy to cause pitting corrosion due to corrosive media. More corrosion resistant.

The heat treatment processes of hot-dip galvanized and electro-galvanized sheets are also completely different. Hot-dip galvanized sheets are generally made of chilled sheets, which are continuously annealed and hot-dip galvanized on the galvanizing line. The steel strips are heated and then cooled in a short time. Therefore, the strength and plasticity are affected to a certain extent, and its stamping performance is worse than that of the same chilled sheet after degreasing and annealing in a professional production line. Electrogalvanized sheet uses cold-rolled sheet as raw material, which basically guarantees the same processing performance of cold-rolled sheet, but its complicated process also increases production costs. In short, the production cost of hot-dip galvanized sheet is lower and the application range is wider, and it has also become the main variety in the galvanized sheet market.