Galvanised steel sheet refers to a steel plate with a layer of zinc coating on its surface, which can prevent the surface of the steel plate from being corroded and extend its service life. Its performance indicators are key parameters for measuring its quality and applicability, mainly including the following aspects:

1、 Appearance quality

Galvanised steel sheets should have a good appearance, with a flat and smooth surface, and no obvious defects such as no plating, holes, cracks, floating slag, exceeding plating thickness, scratches, chromic acid dirt, white rust, etc. These defects will affect the aesthetics and service life of the steel plate.

2、 Size specifications

The size specification is also one of its important performance indicators. The thickness, length, width, and their allowable deviations should comply with relevant standards and specifications. The thickness deviation is generally 0.05mm, the length and width deviation is generally 5mm, and the thickness of the board is generally between 0.4-3.2mm. Galvanised steel sheets of different specifications and sizes are suitable for different application scenarios.

3、 Mechanical performance

1. Tensile strength: Tensile strength is an indicator that measures the maximum tensile force that galvanized steel sheets can withstand during the tensile process. It reflects the strength and toughness of the steel plate.
2. Yield strength: Yield strength is the minimum stress at which plastic deformation occurs when subjected to external forces. It determines the stability of the steel plate when subjected to a certain load.
3. Elongation: Elongation is the percentage increase in length during the stretching process, which reflects the plasticity and toughness of galvanized steel sheets.

In addition, bending test is also an important indicator for measuring the mechanical properties of galvanised steel sheets. Generally, it is required that after the galvanized sheet is bent 180 degrees, there should be no zinc layer detachment on the outer surface, and the base of the sheet should not have cracks or fractures.

4、 Corrosion resistance performance

One of the main advantages of galvanized steel sheet is its excellent corrosion resistance. Due to the presence of the galvanized layer, it can effectively prevent the substrate from coming into contact with the atmosphere, thereby avoiding corrosion and rusting of the substrate. The weight and thickness of the galvanized layer will affect its corrosion resistance. Generally speaking, the heavier and thicker the galvanized layer, the better its corrosion resistance.

5、 Processing performance

Galvanised steel sheets should have good processing performance and can be processed into various shapes and sizes of parts or components through cutting, stamping, bending, welding and other processing techniques. During the processing, attention should be paid to controlling the processing temperature and speed to avoid deformation or cracking of the steel plate due to excessive temperature or speed.

6、 Chemical composition

For specific types, such as DC57D+Z galvanised steel sheets, their chemical composition is also one of the important performance indicators. The content of carbon, silicon, manganese, phosphorus, sulfur and other elements should comply with relevant national standards. The content of these elements will affect the mechanical properties, corrosion resistance, and processing performance of steel plates.
In summary, the performance indicators of galvanized steel sheets include multiple aspects such as appearance quality, size specifications, mechanical properties, corrosion resistance, processing performance, and chemical composition. These performance indicators collectively determine the quality and applicability of galvanised steel sheets, and are also important factors that users need to consider when selecting and using galvanised steel sheets.