Category: galvanized steel coil

Control the Defects of Galvanized Steel Coil

Galvanized steel coil because of its ideal corrosion resistance, forming, welding and coating, and other comprehensive properties and low cost, good appearance, and other advantages, a large number of construction, automobile, household appliances and other industries. In the production of the galvanized coil, there will be linear bulged, raised head grain defects, affecting the quality of products, customer use, need to control.

A. linear projections
The appearance morphology of linear convex defects is generally distributed along the rolling direction in a linear distribution of different lengths, which looks like scratch defects. The difference is that the number of linear convex defects is not fixed, but the relative position is fixed. The cause of the formation of the defect is due to a raw material defect.

Control measures:
1. Optimize composition design of steelmaking process and focus on adjusting manganese sulfur ratio of molten steel; At the same time, the water quantity system of two cold water seasons is formulated to distinguish the disturbance caused by winter and summer season factors.
2. In the continuous casting stage, select the mould without coating on the upper half and coating on the lower half.
3. Strengthen the management of the previous galvanizing process and equipment, and try to avoid scratches caused by the equipment. At the same time, the maximum rolling force of reducing the pass number is considered to reduce the damage of rolled material caused by excessive shearing.

B. defect of forehead wrinkles
Because some of them resemble wrinkles on a person's forehead, they are called forehead wrinkles. Many factors such as transverse striation defect of hot dip galvanizing sheet, the fluidity of zinc solution and the formation of Kirschner air mass in continuous annealing process are easy to lead to the defect of the raised head.

Control measures:
1. Appropriately increase the temperature and steel strip speed of zinc solution, or reduce the aluminum content in zinc solution and increase the height of air knife, so as to increase the fluidity of zinc solution in the air knife area.
2. Increase the press amount of bending roll and improve the bending effect. Increase the number of yield area, reduce the width of yield area, and reduce the forehead wrinkles.
3. Reduce the tensile elongation, that is, reduce the total plastic deformation.
4. Reasonable control of annealing temperature of galvanized steel coil.

Specification of Galvanized Steel Coil


By Alisajpq, 2019-05-24

First of all, to determine the customer requirements is a flower galvanized sheet or hot sale galvanized steel coil without zinc flowers, flowers to be used a little. The thickness of 0.18-3.0mm is commonly used, and the width is mainly concentrated in 1000mm or 1250mm. The relevant product standards all list the recommended standard thickness, length, and width of galvanized sheet and its allowable deviation. The thickness deviation is generally 0.05mm, the length and width deviation is generally 5mm, and the thickness of the plate is generally between 0.4-3.2.

Generally speaking, the thicker galvanized steel coil allows greater error, rather than fixed 0.02-0.04mm, thickness deviation is also based on yield, tensile coefficient, and other different requirements, the width of the deviation is generally in 5mm, the thickness of the galvanized steel coils generally between 0.4-3.2. Common galvanized sheet thickness in 0.4~2.0 is generally less than 0.4mm state-owned big steel mill production, as a private small steel mill production, the general specification is 0.35, 0.30, 0.28, 0.25, generally the thinnest to 0.15 more than 2.0mm due to straightening difficulty is very large, so more than 2.0 with the increase in thickness of the price is also rising.


The low cost Galvanized Corrugated Steel Sheet is used to prevent corrosion of the surface of the steel sheet and prolong its service life. The surface of the steel sheet is coated with a layer of metal zinc. This zinc-coated steel sheet is called a galvanized sheet. Zinc plating is an economical and effective method of preserving corrosion that is often used. About half of the world's zinc production is used in this process.

According to production and processing methods can be divided into the following categories:

1. The hot dip galvanized steel coil for sale. The steel sheet is immersed in a molten zinc bath to adhere to a zinc-plated steel sheet to the surface. At present, it is mainly produced by a continuous galvanizing process, that is, a coiled steel plate is continuously immersed in a plating tank in which zinc is melted to form a galvanized steel sheet;

2. Alloyed galvanized steel sheet. This steel sheet is also produced by hot dip, but immediately after it is discharged, it is heated to about 500 ° C to form an alloy film of zinc and iron. This galvanized sheet has good adhesion and weldability of the coating;

3. Electro-galvanized steel plate. The production of such a galvanized steel sheet by electroplating has good processability. However, the coating is thinner and the corrosion resistance is not as good as that of hot-dip galvanized sheet;

4. Single-sided plating and double-sided differential galvanized steel. Single-sided galvanized steel, that is, a product that is only galvanized on one side. It has better adaptability than a double-sided galvanized sheet in welding, painting, anti-rust treatment, and processing. In order to overcome the shortcomings of uncoated zinc on one side, there is a galvanized sheet coated with a thin layer of zinc on the other side, that is, a double-sided differential galvanized sheet;

5. Alloy, composite galvanized steel sheet. It is made of zinc and other metals such as aluminum, lead, zinc, etc., or even composite plated steel. This steel plate has excellent rust resistance and good coating properties;

In addition to the above five types, there are also hot sale color-coated corrugated roofing sheet, printed galvanized steel sheets, and polyvinyl chloride laminated galvanized steel sheets. However, the most commonly used ones are still hot dip galvanized sheets.

Galvanized steel products are mainly used in construction, light industry, automotive, agriculture, animal husbandry, and fishery and commercial industries. The construction industry is mainly used to manufacture anti-corrosion industrial and civil building roof panels, roof grills, etc.; the light industry uses it to manufacture home appliance casings, civil chimneys, kitchen utensils, etc., and the automotive industry is mainly used to manufacture corrosion-resistant parts for cars, etc. Agriculture, animal husbandry and fishery are mainly used for grain storage and transportation, frozen processing tools for meat and aquatic products, etc.; commercial is mainly used as storage, transportation, and packaging equipment for materials.

What is a galvanized steel coil? As the name suggests, The hot sale prepainted galvanized steel coil are steel sheets coated with a layer of zinc. Galvanizing on steel sheets is one of the most economical and effective ways to avoid rusting of steel sheets. Due to its high cost performance, galvanized steel coils are used. Widely used in the production of outdoor billboards. Advantages of galvanized steel coils: 1. The galvanized steel coil has been widely used in adapting to the environment, and the corrosion protection period is long, but the corrosion protection period is different in different environments. 2. The processing cost is low, and the cost of rust-proofing of galvanized coils is lower than that of other paint coatings. 3. Durable, in the suburban environment, the standard galvanized rust layer can be maintained for more than 50 years without having to repair. In urban or offshore areas, the standard galvanized rust-proof layer can be maintained for 20 years without having to be repaired. 4. The reliability is good. The galvanized coil and the steel are metallurgically combined and become a part of the surface, so the durability of the coating is relatively reliable. 5. The toughness of the coating is strong, and the galvanized coil forms a special metallurgical structure that can withstand mechanical damage during transportation and use. 6. Integral protection, each part of the plated parts can be plated with zinc, which can be fully protected even in depressions, sharp corners and hidden places. 7. Save time and effort, the galvanizing process is faster than other coating methods, and can avoid the time required to paint on the construction site after installation.

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