Galvanized steel sheet classification and galvanized content

According to production and processing methods can be divided into the following categories:
a) Hot dip galvanized steel sheet. The steel sheet is immersed in a molten zinc bath and a zinc thin steel sheet adheres to the surface. At present, the main continuous galvanizing process is adopted, that is, the rolled steel sheet is continuously immersed in a zinc plating bath to form a galvanized steel sheet.
b) Alloyed galvanized steel sheet. This steel sheet is also manufactured by a hot dip method, but immediately after it is discharged, it is heated to about 500°C to produce an alloy film of zinc and iron. This galvanized sheet has good coating adhesion and weldability.
c) Electro-galvanized steel sheet. This galvanized steel sheet manufactured by electroplating has good processability. However, the plating layer is thinner and the corrosion resistance is inferior to the hot dip galvanizing plate.
d) Single sided and double sided galvanized steel. Single-sided galvanized steel, ie galvanized on one side only. In welding, painting, anti-rust treatment, processing, etc., has better adaptability than double-sided galvanized sheet. In order to overcome the disadvantages of the single-sided uncoated zinc, there is another galvanized sheet coated with a thin layer of zinc on the other side, ie, a double-sided differential galvanized sheet;
e) Alloy, composite galvanized steel sheet. It is an alloy made of zinc and other metals such as lead and zinc, or even a composite plated steel plate. This steel sheet has both excellent rust resistance and good coating performance.
In addition to the above-mentioned five kinds, there are also colored galvanized steel sheets, printed galvanized steel sheets, and PVC laminated galvanized steel sheets. However, hot dip galvanized sheets are still the most commonly used.
Galvanized steel sheets can also be classified into general-purpose, roof-use, construction-outboard, structural-use, tile-retaining, tensile, and deep-drawing galvanized steel.
Major production plants and import production countries:
a) Domestic: Wuhan, Anshan Iron and Steel, Baosteel and Guangdong;
b) Foreign countries: Japan, Germany, Russia, France, etc.
[Dimensions]
The relevant product standards list the recommended standard thickness, length and width of galvanized sheet and their tolerances. See the relevant product standards provided in the last section.
[Exterior]
(1) Surface state: The galvanized sheet has different surface conditions due to different treatment methods in the plating process, such as ordinary zinc flower, fine zinc flower, smooth zinc flower, non-zinc flower, and phosphating surface. German standards also specify a surface level.
(2) The galvanized sheet should have a good appearance and must not be detrimental to the use of the product, such as non-plating, holes, cracks and scum, excessive plating thickness, scratches, chromic acid dirt, white rust, etc. Foreign standards are not very clear about specific appearance defects. Specific defects should be specified in the contract when ordering.
[galvanizing amount]
(1) Standard value of galvanizing amount: The galvanized amount is a commonly used effective method for expressing the zinc layer thickness of the galvanized sheet. The unit for galvanizing is g/m2.
The specifications of galvanized steel sheets for galvanizing in Japan, the United States, and Germany are detailed in “Table 1”.
(2) Measurement methods: The sampling requirements and test methods are given in the relevant section in the last section.
[Mechanical behavior]
(1) Tensile test:
Table 1 Index of galvanized steel sheet (unit: g/m2)
JISG3302
Code Z12
Z18
Z22
Z25
Z27
Z35
Z43
Z50
Z60
The amount of zinc plating 120
180
220
250
270
350
430
500
600
ASTMA 525
Code A40
A60
G60
G90
G115
G140
G165
G185
G210
Zinc coating amount 122
183
183
275
351
427
503
564
640
DIN1716
Code number 100
200
275
350
450
600
Galvanizing amount 100
200
275
350
450
600
a) Performance indicators: Generally speaking, only the galvanized sheet for structural, tensile and deep drawing has tensile performance requirements. The galvanized sheet for structural use requires a yield point, tensile strength, and elongation; elongation requires only elongation. For specific values, see the relevant product standards in the last section of this section;
b) Test method: the same as the general steel sheet test method, see the relevant standards provided in the last section and the test method standards listed in “General carbon steel sheet”.
(2) Bending test:
The bending test is the main item to measure the technical performance of the sheet, but the standards of various countries are not consistent with the requirements of various galvanized sheets. The US standard does not require bending and tensile tests except for the structural level. In Japan, bending tests are required except for structural grades, building corrugated plates, and general corrugated plates.
1 Requirements: General requirements galvanized sheet after bending 180, the outer surface may not be separated from the zinc layer, the base shall not have cracks and fractures;
2 Test method: See the relevant product standard in the last section for sampling locations and quantities. The bending angle is 180, the ratio of the inner spacing to the plate thickness of the test sample, see relevant product standards listed in the last section.