Features of Hot-Dip Galvanized/Hot-Dip Galvanized Channel Steel

Hot-dip galvanized channels are an effective way to avoid corrosion of metals. It is to put the rust-removed channel steel into the molten zinc at about 440~460 ℃, so that the surface of the channel steel can then adhere to the zinc layer, so as to achieve the purpose of anticorrosion.

The main method of galvanizing the surface of channel steel is hot-dip galvanizing

Among various coating methods for protecting steel substrates, hot-dip galvanizing is a very good one. It is in the liquid state of zinc, after quite complex physical and chemical actions, not only a thicker layer of pure zinc is plated on the steel, but also a zinc-iron alloy layer is formed. This plating method not only has the corrosion resistance characteristics of electro-galvanizing, but also has a zinc-iron alloy layer. It also has strong corrosion resistance that cannot be compared with electro-galvanized. Therefore, this plating method is especially suitable for strong corrosive environments such as various strong acids and alkali mist.

The specification of galvanized channel steel is expressed by the number of millimeters of waist height (h)* leg width (b)* waist thickness (d), 120*53*5, indicating that the waist height is 120 mm, the leg width is 53 mm, and the waist thickness is 5 mm, or 12# channel steel. Channel steel with the same waist height, if there are several different leg width and waist thickness, also need to add a, b, c on the right side of the model to distinguish, such as 25a# 25b# 25c#.

Peculiarity

1. With a thick dense pure zinc layer covered on the surface of the steel, it can avoid the steel matrix and any corrosion solution contact, protect the steel matrix from corrosion. In the general atmosphere, the surface of the zinc layer forms a thin and dense zinc oxide layer surface, which is difficult to dissolve in water, so it plays a certain protective role on the steel matrix. If zinc oxide and other components in the atmosphere to form insoluble zinc salt, the corrosion protection is more ideal.

2. It has an iron-zinc alloy layer, which is densely combined, and exhibits unique corrosion resistance in marine salt spray atmosphere and industrial atmosphere;

3. Due to the firm combination, zinc-iron is soluble in each other and has strong wear resistance;

4. Due to the good ductility of zinc, its alloy layer is firmly attached to the steel base, so the hot-dip parts can be cold punched, rolled, drawn, bent, etc. without damaging the coating;

5. After hot-dip galvanizing of steel structural parts, it is equivalent to one-time annealing treatment, which can effectively improve the mechanical properties of the steel matrix, eliminate the stress of steel parts during forming and welding, and facilitate turning processing of steel structural parts.

6. The surface of the parts after hot-dip galvanizing is bright and beautiful

7. The pure zinc layer is the most plastic galvanized layer in hot-dip galvanizing. Its properties are basically close to pure zinc, and it has ductility, so it is flexible.

Application range

The application of hot-dip galvanized channel steel has also expanded correspondingly with the development of industry and agriculture. Therefore, hot-dip galvanized products are used in construction (such as: glass curtain walls, power towers, communication grids, water and gas transmission, wire casings, scaffolding, houses, etc.), bridges, transportation; industries (such as chemical equipment, petroleum processing, marine exploration, etc.) , metal structures, power transmission, shipbuilding, etc.); agriculture (such as: sprinkler irrigation, warming houses), etc., have been widely used in recent years.

Because hot-dip galvanized products have the characteristics of beautiful appearance and good corrosion resistance, their application range is more and more extensive.

Hot dip galvanizing process of galvanized channel steel

Hot-dip galvanized channel steel can be divided into hot-dip zinc channel steel and hot-blow galvanized channel steel according to the different galvanizing process, which is to immerse the steel parts after rust removal into the melting zinc liquid about 440~460℃, so that the surface of the steel members are attached with zinc layer, so as to play the purpose of anti-corrosion.

Off-line annealing means that before hot rolled or cold rolled steel enters the hot galvanized line, recrystallization annealing is first carried out in the draw bottom annealing furnace or cover annealing furnace, so that there is no annealing process in the galvanized line.

Steel must maintain a clean pure iron active surface free of oxides and other dirt before hot-dip galvanizing. This method first removes the annealed surface oxide sheet by pickling, and then coats it with a layer of zinc chloride or a solvent composed of ammonium chloride and zinc chloride to protect it, thereby preventing the steel from being oxidized again.

In-line annealing is the process of gas protected recrystallization annealing in the hot-dip galvanizing line, which is directly provided by the cold rolling or hot rolling workshop as the raw plate of hot-dip galvanizing.