The standard for the thickness of the galvanized layer of galvanized sheets is established to ensure that the workpiece can meet different thickness requirements after being galvanized. Depending on the thickness of the workpiece, the average thickness and local thickness standards of the galvanized layer also vary.
For workpieces with a thickness greater than or equal to 6 mm, the average thickness of the galvanized layer should be greater than 85 microns, and the local thickness should be greater than 70 microns. This means that if the thickness of the workpiece reaches or exceeds 6 mm, the thickness of the galvanized layer should also meet or exceed these two standards accordingly.
For workpieces with a thickness less than 6 mm but greater than 3 mm, the average thickness of the galvanized layer should be greater than 70 microns, and the local thickness should be greater than 55 microns. For workpieces with a thickness less than 1.5 mm but greater than 1.5 mm, the average thickness of the galvanized layer should be greater than 55 microns, and the local thickness should be greater than 45 microns.
It is worth noting that this standard does not include the thickness of centrifugally separated coatings and galvanized iron castings. This is because the galvanizing thickness requirements in these special cases may differ from those in general.
In general, the standard for galvanized layer thickness of galvanized sheets is established to ensure that the galvanized workpiece can meet the requirements of practical applications, and the thickness of the galvanized layer needs to be adjusted according to the different thicknesses of the workpiece. These standards refer to the GB/T 13912-2002 national standard.
There are two methods for galvanizing thin sheets: hot plating and electroplating. The hot-dip zinc layer is thick and provides strong protection for steel; while the electroplated zinc layer is like a delicate yarn, which although light and thin, can provide sufficient protection.
The thickness of hot-dip zinc layer is generally 60-300g/m2. This hot-dip galvanizing method is mainly used for parts that require strong corrosion resistance.
The electroplated zinc layer is relatively thin, only 10-50g/m2. This method of electro-galvanizing is mainly used for painted or unpainted parts that do not require high corrosion resistance.
As for the ASTM A123 standard implemented in the hot-dip galvanizing standard for steel grating, this is like a detailed guideline that sets clear standards for the hot-dip galvanizing process of steel grating. In this standard, for steel gratings with a flat steel thickness between 1.5mm and 3.0mm, the average thickness of the zinc layer shall not be less than 55um, the thickness of the local zinc layer shall not be less than 45um, and the weight of the zinc layer shall be between 355g and 390g; and For steel gratings with a thickness of flat steel between 3.0mm and 6.0mm, the average thickness of the zinc layer shall not be less than 70um, the thickness of the local zinc layer shall not be less than 55um, and the zinc weight shall be between 460g and 530g; for flat steel with a thickness between For steel gratings above 6.0mm (including 6.0mm), the average thickness of the zinc layer shall not be less than 85um, the thickness of the local zinc layer shall not be less than 75um, and the weight of the zinc layer shall be more than 600g. These numbers are like a clear indicator, providing clear guidance for the hot-dip galvanizing process of steel grating.
Standard specifications for zinc coating thickness of galvanized steel sheets:
Zinc coating standards for hot-dip galvanized steel grating products: First, for hot-dip galvanized steel gratings with a thickness greater than or equal to 6mm, the average thickness should be greater than 85 microns, and the local thickness should be greater than 70 microns.
Secondly, for hot-dip galvanized steel gratings with a thickness less than 6mm and greater than 3mm, the average thickness should be greater than 70 microns, and the local thickness should be greater than 55 microns.
Finally, for hot-dip galvanized steel gratings with a thickness less than 3mm and greater than 1.5mm, the average thickness should be greater than 55 microns, and the local thickness should be greater than 45 microns.
Advantages of hot dip galvanizing:
1. Low treatment cost: Hot-dip galvanizing anti-rust cost is lower than other paint coatings.
2. Durable: In suburban environments, the standard hot-dip galvanized rust-proof thickness can last for more than 50 years without repairs; in urban or offshore areas, it can last for 20 years without repairs.
3. Good reliability: The galvanized layer is metallurgically combined with the steel and becomes part of the steel surface, so the durability of the coating is relatively reliable.
4. The coating has strong toughness: The galvanized layer forms a special metallurgical structure and can withstand mechanical damage during transportation and use.
5. Comprehensive protection: Every part of the plated part can be coated with zinc, even in recesses, sharp corners and hidden places, it can be fully protected.
6. Save time and effort: The hot-dip galvanizing process is faster than other coating construction methods and can avoid the time required for painting on the construction site after installation.
7. Low initial cost: In general, the cost of hot-dip galvanizing is lower than applying other protective coatings, because other protective coatings such as sandblasting and painting are labor-intensive processes, while the process of hot-dip galvanizing is highly mechanized and precise. Controlled in-plant construction.
Summary
This article introduces in detail the zinc layer thickness standards for galvanized sheets, including the average thickness and local thickness standards for different workpiece thicknesses, as well as the zinc layer thickness standards for hot plating and electroplating of thin sheet galvanizing. It also introduces the application of steel gratings. The ASTM A123 standard implemented in the hot-dip galvanizing standard and the standard specifications for the thickness of the zinc layer of galvanized steel sheets are included. At the same time, the advantages of hot-dip galvanizing are also summarized.