Difference Between Galvanized Steel Sheet and Cold Rolled Steel Sheet
Date:2022-06-29View:480Tags:
1. Galvanized steel sheet:
Galvanized sheet refers to a steel sheet with a layer of zinc plated on the surface. Galvanizing is an economical and effective anti-rust method that is often used to prevent the surface of the steel plate from being corroded and prolong its service life.
Classification:
①Hot dip galvanized steel sheet. The sheet steel is immersed in a molten zinc bath, and a sheet of zinc is adhered to its surface. At present, it is mainly produced by continuous galvanizing process, that is, galvanized steel plate is made by continuously immersing rolled steel plates in a plating tank in which zinc is melted.
Hot-dip galvanized steel has an advantage over electro-galvanized steel. Electro-galvanized steel is very easy to rust on bends and sections. Under the same conditions, hot-dip galvanized steel has much better rust resistance. High-quality chassis is usually made of electrolytic or hot-dip galvanized steel plate. The chassis steel plate made of this material is bright in color and has a metallic luster. The advantage of this kind of steel plate is that it has good corrosion resistance.
Hot-dip galvanized steel is more resistant to corrosion than cold-rolled steel. The characteristics of hot-dip galvanized steel sheet are strong corrosion resistance, good surface quality, favorable for deep processing, economical and practical. The drawability of hot-dip galvanized steel is not as reliable as that of cold-rolled steel. Hot-dip galvanized steel is not as easy to weld as cold-rolled steel, and the zinc layer is damaged during welding.
②Alloyed galvanized steel sheet. This kind of steel plate is also made by hot-dip method, but after it is out of the tank, it is heated to about 500 ℃ immediately to form an alloy film of zinc and iron. This galvanized sheet has good paint adhesion and weldability.
③ Electro-galvanized steel sheet. The galvanized steel sheet produced by the electroplating method has good workability. However, the coating is thin, and the corrosion resistance is not as good as that of hot-dip galvanized sheet (a commonly used type of test bench cabinet). Mainly used in home appliances, computer case shells and some door panels and panels.
④Single-sided and double-sided differential galvanized steel. Single-sided galvanized steel sheet, that is, a product that is galvanized on only one side. In welding, painting, anti-rust treatment, processing, etc., it has better adaptability than double-sided galvanized sheet. In order to overcome the disadvantage of not being coated with zinc on one side, there is another galvanized sheet coated with a thin layer of zinc on the other side, that is, double-sided differential galvanized sheet.
⑤Alloy and composite galvanized steel sheet. It is made of zinc and other metals such as aluminum, lead, zinc, etc. to make alloys or even composite plated steel plates. This kind of steel plate has both excellent anti-rust properties and good coating properties.
In addition to the above five types, there are also colored galvanized steel sheets, printed and painted galvanized steel sheets, and PVC laminated galvanized steel sheets. But the most commonly used is still hot-dip galvanized sheet.
2. Cold rolled steel plate:
Cold rolled steel is steel produced by cold rolling. Cold rolling is a steel sheet in which the steel sheet is further thinned to a target thickness at room temperature. Compared with hot-rolled steel sheet, cold-rolled steel sheet has more accurate thickness, smooth and beautiful surface, and also has various superior mechanical properties, especially in terms of processability. Because the cold-rolled raw coil is relatively brittle and hard, it is not suitable for processing, so usually cold-rolled steel plates need to be annealed, pickled, phosphating and surface smoothed.
The difference between cold-rolled steel and hot-rolled steel is not in the smelting process, but in the rolling temperature, or the end temperature of rolling. Cold-rolled steel is when the final rolling temperature is lower than the recrystallization temperature of the steel. Hot-rolled steel is easy to roll and has high rolling efficiency, but under hot-rolled conditions, the steel is oxidized, and the surface of the product is dark gray. Cold-rolled steel requires high rolling mill power and low rolling efficiency, and intermediate annealing is required to eliminate work hardening during the rolling process, so the cost is also high, but cold-rolled steel has a bright surface and good quality, and can be directly used for processing. The finished product, so cold-rolled steel sheet is widely used.
Cold-rolled sheet is a product obtained from hot-rolled sheet by cold pressing. Due to the multi-pass cold rolling, the surface quality is better than that of the hot-rolled sheet, and good mechanical properties can be obtained after heat treatment.
Summary: In terms of anti-corrosion performance under the same conditions, galvanized steel sheet has better performance than cold-rolled steel sheet, and the coating of galvanized steel sheet is mainly to prevent oxidation corrosion. The corrosion resistance of cold-rolled steel sheets is slightly poor, and the steel sheets will oxidize and rust when exposed to air.
The thickness accuracy and strength of cold-rolled sheet are relatively high. In addition, zinc alloy and stainless steel have extremely strong corrosion resistance, and their price is much higher than that of galvanized sheet.
The base material of galvanized steel sheet is cold-rolled sheet or hot-rolled sheet, and the drawing performance of galvanized steel sheet is not as reliable as that of cold-rolled sheet. Galvanized steel is not as easy to weld as cold-rolled steel, and the zinc layer is damaged during welding.
Cold-rolled steel sheet and galvanized steel sheet have their own advantages and disadvantages. The price difference is within 1,000 yuan per ton, and the effect of spraying and painting on the surface is not as great as expected. The surface paint of galvanized steel sheet falls off after a period of use. It is just as easy to rust, and it is not as amazing as some manufacturers boast. It is mainly to use the characteristics that the user unit does not understand to raise its price.
