Galvanized steel plate is a welded steel plate with hot-dip or electro galvanized coating on the surface, which is widely used in construction, household appliances, vehicles and ships, container manufacturing, electromechanical industry, etc.
Galvanized steel plate is divided into ordinary electrolytic plate and fingerprint resistant electrolytic plate. Fingerprint resistant plate is a fingerprint resistant treatment added to the ordinary electrolytic plate, which can resist sweat. It is generally used on parts without any treatment, and the brand is secc-n. Ordinary electrolytic plates can be divided into phosphating plates and passivation plates. Phosphating is commonly used, and the brand is secc-p, commonly known as P material. Passivation plate can be coated with oil or not.
For an example:
- Hot dip galvanized steel plate (SGCC) has an advantage over electro galvanized steel plate (SECC). The bending and section of SECC are very easy to rust, and the rust resistance of SGCC is much better under the same conditions. High quality chassis is usually made of SECC or SGCC galvanized steel plate. The chassis steel plate made of this material has bright color and metallic luster. The advantage of this steel plate is good corrosion resistance.
- Electro galvanized steel plate (SECC): uniform gray, mainly imported, fingerprint resistant, excellent corrosion resistance, and maintaining the processability of cold-rolled plate. Uses: home appliances, computer cases, and some door panels and panels.
Divided by zinc: the size of zinc flower and the thickness of zinc layer can indicate the quality of zinc plating. The smaller the thickness, the better. Manufacturers can also add fingerprint resistant treatment. In addition, it can be distinguished by its plating layer. For example, Z12 represents the total amount of double-sided plating layer 120 g / mm.
The hot-dip galvanized steel plates produced by Chinese manufacturers are mainly used in building materials, light industry, agriculture, transportation and other industries. Due to the limitations of the existing hot-dip galvanizing equipment conditions, process technology and the performance of the original plate, there are very few galvanized plates that can be used in the automobile manufacturing industry.
Characteristic
Features of galvanized steel plate: galvanizing can effectively prevent steel corrosion and prolong service life. Galvanized steel sheet (thickness: 0.4-1.2mm) is also known as galvanized iron sheet, commonly known as white iron sheet. Galvanized steel sheet is widely used in construction, vehicles, household appliances, daily necessities and other industries.
Classification
According to the production and processing methods, it can be divided into the following categories:
① hot dip galvanized steel plate. Immerse the steel sheet in the molten zinc bath to make the surface of the steel sheet adhere with a layer of zinc. At present, it is mainly produced by continuous galvanizing process, that is, the rolled steel plate is continuously immersed in the zinc bath to make galvanized steel plate;
② Alloyed galvanized steel plate. This kind of steel plate is also made by hot-dip method, but it is heated to about 500 ℃ immediately after being out of the tank to form an alloy film of zinc and iron. The galvanized sheet has good coating adhesion and weldability;
③ Electro galvanized steel plate. The galvanized steel sheet produced by electroplating method has good processability. But the coating is thin and the corrosion resistance is not as good as that of hot dip galvanized sheet;
④ single side plating and double side difference galvanized steel plate. Single side galvanized steel plate, i.e. products galvanized on one side only. It has better adaptability than double-sided galvanized sheet in welding, coating, rust prevention treatment and processing. In order to overcome the disadvantages of one side not coated with zinc, there is another kind of galvanized sheet coated with thin layer of zinc on the other side, namely, double-sided poor galvanized sheet;
⑤ Alloy and composite galvanized steel plate. It is a steel plate made of zinc and other metals such as aluminum, lead, zinc and so on. This kind of steel plate has good coating performance;
In addition to the above five types, there are also colored galvanized steel plates, printed and coated galvanized steel plates, and PVC laminated galvanized steel plates. But at present, the most commonly used is still hot-dip galvanized plate.
Quality inspection standard
The quality requirements of high-grade galvanized sheet include specification, size, surface, galvanized amount, chemical composition, sheet shape, machine function and packaging.
- Packaging
It is divided into two types: galvanized sheet cut to length and rolled galvanized sheet packaging. The general iron sheet packaging is lined with moisture-proof paper, and bound with iron waist to prevent the internal galvanized plates from rubbing against each other.
- Specification and size
Relevant product dimensions (such as the following and) list the recommended dimension thickness, length, width and allowable defects of galvanized sheet. In addition, the width and length of the plate and the width of the roll can also be determined according to the user’s request.
- Surface
Overview: due to different treatment methods in the coating process, the overview of galvanized sheet is also different, such as the overview of ordinary zinc flower, fine zinc flower, flat zinc flower, no zinc flower and phosphating treatment. The galvanized sheet and galvanized coil cut to length shall not have defects that affect the use, but the coil shall be allowed to have less deformed parts such as welding parts.
- Galvanizing amount
Scale value of galvanizing quantity: measuring galvanizing quantity is a widely adopted method to determine the thickness of zinc layer of galvanized sheet. There are two kinds of galvanizing: the same amount of galvanizing on both sides (i.e. equal thickness galvanizing) and the different amount of galvanizing on both sides (i.e. different thickness galvanizing). The unit of galvanizing amount is g / m2.
- Machine function
(1) Tensile test: Generally speaking, as long as the galvanized sheet for layout, drawing and deep drawing has tensile function requirements.
(2) Bending experiment: it is an important item to weigh the process function of thin plate. However, the requirements of all kinds of galvanized sheets are different in the world. It is generally required that after the galvanized plate is bent for 180o, the outer plating layer shall not be separated from the zinc layer, and the plate base shall not be cracked or broken.
- Chemical composition
The requirements for the chemical composition of galvanized substrates vary from country to country. If Japan has such requirements, the United States has none. Generally, product inspection is not required.
