How to distinguish electro-galvanized steel sheets from hot-dip galvanized steel sheets?

Hot-dip galvanizing can also be called hot-dip galvanizing. Hot-dip galvanizing sheets are made by immersing thin steel sheets in a dissolved zinc bath so that a layer of zinc is absorbed on the surface of the thin steel sheets. So far, they are mainly produced using the process of repeated galvanizing. That is, the entire roll of material is repeatedly immersed in a plating bath containing dissolved zinc to extract galvanized steel sheets.

Electro-galvanizing, also known as cold galvanizing, uses electrochemistry. The zinc ingot is used as the anode. The zinc atoms lose their electrons and become ions and dissolve into the electrolyte. The steel strip is used as the cathode, and the zinc ions are in the steel strip. The electrons obtained from the steel strip reduce the zinc atoms and precipitate to the outside of the steel strip to form a coating. The thickness of the galvanized layer is different between hot-dip galvanized sheets and electro-galvanized sheets.

The galvanizing amount of hot-dip galvanized steel sheets cannot be too small. Generally speaking, it is at least 50-60g/m2 on both sides and can reach up to 600g/m2. The galvanized layer of electro-galvanized sheets can also be very thin, at least 15g/m2, and up to about 100g/m2. In addition, electro-galvanizing can also be galvanized on only one side, or double-sided galvanizing. Hot-dip galvanized steel panels must be galvanized on both sides.

There are principled differences in the coating structure between hot-dip galvanized sheets and electro-galvanized sheets. There is a slightly brittle compound layer between the pure zinc coating of the hot-dip galvanized sheet and the conventional steel strip. When the pure zinc coating crystallizes, most of the zinc blooms are generated, and the coating is uniform and has no pores. The zinc atoms in the electroplated zinc layer only precipitate and precipitate outside the steel strip, and they adhere to the outside of the steel strip due to physical effects. There are many holes for drying, and it is easy to cause pitting corrosion due to corrosive media. Therefore, hot-dip galvanized sheets are better than electroplated sheets. Zinc sheets are more resistant to corrosion.

The heat treatment processes of hot-dip galvanized steel sheets and electro-galvanized sheets are different

Generally speaking, hot-dip galvanized steel sheets are made of chilled steel sheets, and are repeatedly annealed and hot-dip galvanized steel sheets on the galvanizing line. The steel strips are heated in a short period of time and then cooled again, which affects the strength and plasticity to a certain extent. Electrogalvanized sheets use cold-rolled steel sheets as raw materials, which basically ensures the same processing performance of cold-rolled steel sheets. However, its complex process also increases the processing cost.

galvanized sheet

Compared with hot-dip galvanized steel sheets, electro-galvanized steel sheets have the characteristics of thick zinc layer, good corrosion resistance, and low manufacturing cost.

During the process of hot-dip galvanizing steel sheets, the zinc liquid is attached to the outside of the material when the material passes through the zinc pot, and the air knife blows away the excess zinc liquid, so it is easy to produce materials with thick coatings. In recent years, in order to reduce processing costs and meet environmental protection requirements, domestic automobile and home appliance companies have gradually used hot-dip galvanized sheets instead of electro-galvanized steel sheets.

Galvanized products are widely used in construction, communications, electric power, transportation, energy, automobiles, light industry (household appliances), agriculture, animal husbandry, fishery, petrochemical and other industries. Their main uses are as follows:

(1) Light industry and household appliance industry: casings and base plates of household appliances such as air conditioners, televisions, washing machines, refrigerators, microwave ovens, water heaters, computer base plates and casings, civil chimneys, kitchen utensils, buckets, containers, etc.

(2) Electric power and communication industry: power transmission and transformation towers, communication towers, cable armored belts, galvanized low carbon steel wire for communications, galvanized steel wire for steel core aluminum hinges, galvanized steel wire for hangers, suspension and fastening Strand. Pole cross arms, cables and fasteners, various cable trays.

(3) Construction industry: light steel keels for various industrial and civil buildings, building floor panels, corrugated boards, roof grilles, galvanized for ventilation, water supply and drainage projects