Galvanizing method for hot-dip galvanized strip

I. The significance of hot-dip galvanized strip

Cold-formed thin-walled steel is generally made of black material a few days ago. After cold-formed, it is put into use after simple rust removal coating. Its service life is limited to a certain extent (generally, large areas of rust will appear in about 5 years). And "the hot-dip galvanized strip steel grandly launched by our company to the market is based on hot-rolled strip steel and is produced through pickling, cold rolling, heating reduction, galvanizing and other processes. Its products can fully meet the GB510018-2002 "Cold" The standards of "Technical Specifications for Curved Thin-walled Steel Structures" can be widely used in the construction industry, and can also be used in automobile and railway locomotive manufacturing Used in industries such as warehouse board manufacturing and highway guardrails.

2. Galvanizing method of hot-dip galvanized strip

1. Hydrogen reduction method galvanizing Hydrogen reduction method galvanizing was invented in 1937. Hydrogen reduction method hot-dip galvanizing laid the foundation for modern continuous hot-dip galvanizing. Products using the hydrogen reduction method production process have better appearance quality and galvanized layer bonding force than solvent method galvanizing. Reduction method galvanizing enters the heating reduction furnace after the strip steel is pickled, and uses hydrogen to reduce the oxide film produced after pickling. During the heating and reduction process, a sponge-like reduction layer is produced on the surface of the steel plate. After entering the zinc pot, A zinc-iron alloy layer with good bidirectional bonding force and uniformity can be produced, which greatly increases the adhesion of the zinc layer This also determines the high cost of its galvanizing method for energy consumption.

2. Ammonium chloride solvent method galvanizing Ammonium chloride solvent method galvanizing was invented in 1837. Products using the ammonium chloride solvent method production process, since the ammonium chloride solvent method galvanizing has no heating reduction process, the appearance quality and the surface bonding force of the galvanized layer are slightly worse than those of the hydrogen reduction method galvanizing. This also determines that its galvanizing method has a somewhat lower energy consumption cost than hydrogen reduction galvanizing.

3. Galvanizing amount The galvanizing amount of steel plates is generally 180-220g/㎡. In humid southern areas, the galvanizing amount can be increased to 275g/㎡ to increase the service life of steel components. The service life of galvanized products is generally 20-25 years.

4. Characteristics of the zinc layer of galvanized strip steel The electro-galvanized layer cannot form zinc flowers, while the hot-dip galvanized layer has zinc flowers. The formation process is as follows: when the galvanized strip comes out of the zinc pot, it is sprayed by an air knife, a large amount of zinc liquid is blown back into the zinc pot. At this time, there is a pure zinc layer on the surface of the strip steel, which is attached to the surface of the steel plate in a liquid state A large number of crystalline nuclei are formed on the surface of the steel sheet, and as the steel sheet rises and cools, the crystalline nuclei slowly grow into zinc flowers. The faster the cooling rate, the smaller the zinc flower, and the slower the cooling rate, the larger the zinc flower.