Galvanized steel sheet is a common metal material widely used in construction, home appliances, automobiles, and other fields. To ensure the quality and performance of galvanized steel sheet, the country has strict standards for the thickness of its zinc coating.
The national standard thickness of the zinc coating on galvanized steel sheet varies depending on the type of galvanizing process. Generally, the thickness of hot-dip galvanized coatings ranges from 60 to 180 g/m², while the thickness of electroplated galvanized coatings typically ranges from 5 to 100 g/m².
International and Domestic Standards for Galvanized Coating Thickness
The zinc coating thickness of galvanized steel sheet is primarily expressed as the zinc coating mass per unit area (g/m²) or thickness (μm). Different standards use different designations:
1. International Standard (ISO 3575):
Common designations: Z100, Z200, and Z275 (the number represents the total zinc coating weight on both sides; for example, Z275 represents 275 g/m² on both sides). Conversion thickness: Every 10 g/m² ≈ 1.4 μm, for example, Z275 ≈ 38.5 μm (approximately 19.25 μm per side).
2. American Standard (ASTM A653):
Codes: G60 (60 g/m² zinc coating on one side), G90 (90 g/m² zinc coating on one side). Double-sided coating requires x2.
Typical Applications: G60 for general corrosion protection, G90 for harsh environments (such as coastal areas).
3. Chinese Standard (GB/T 2518):
Codes: Z80, Z120, Z180, etc., corresponding to the total zinc coating weight on both sides.
Special Requirements: Single-sided galvanized coating must be marked with “S” (e.g., Z60S indicates 60 g/m² zinc coating on one side). References:
ISO 3575:2014 “Cold-Rolled Galvanized Steel Sheet”
ASTM A653-23 “Standard Specification for Hot-Dip Galvanized Steel Sheet”
GB/T 2518-2019 “Continuously Hot-Dip Galvanized Steel Sheet and Strip”
The correspondence between G and Z designations can be summarized as follows:
G90 galvanized steel sheet corresponds to Z275 galvanized steel sheet
G75 corresponds to Z230
G70 corresponds to Z215
G65 corresponds to Z200
G60 corresponds to Z180
G50 corresponds to Z150
G40 corresponds to Z120
Specification Differences and Applications for Single-Sided and Double-Sided Galvanizing
1. Single-Sided Galvanizing:
Specification: Only one side has a zinc coating, the other side is bare steel (requires an “S” suffix).
Applications: Commonly used in applications requiring corrosion protection on only one side, such as appliance back panels and interior linings. 2. Double-Sided Galvanizing:
Specifications: The zinc coating thickness on both sides can be the same (symmetrical) or different (asymmetrical).
Asymmetrical galvanizing: For example, “Z180/Z100” indicates 180g/m² on the front and 100g/m² on the back. This is suitable for applications such as automotive sheeting that require different internal and external corrosion protection.
What are the grades of hot-dip galvanized steel and electro-galvanized steel, and what are the differences?
The processes are different. Hot-dip galvanizing is hot-dip galvanizing, while electro-galvanizing is electroplating.
Common hot-dip galvanized steel grades include: DX51D, DX53D, DX4D, DX56D, DC51D, DC53, DC54D, DC56D, SGCC, SGCD, etc.
Common electro-galvanized steel grades include: SECC, SECD, SECE, DC01+ZE, DC03+ZE, DC04+ZE
Galvanized steel comes in a variety of sizes and thicknesses, suitable for a variety of applications. Typically, the thickness of galvanized steel can range from 0.12mm to 4.0mm, but the most common thickness range is 0.4mm to 1.5mm. For industrial and construction applications, galvanized steel widths typically range from 600mm to 1700mm. However, the size and thickness of galvanized steel can be customized to meet specific customer requirements. If you want to know the price of galvanized steel sheets, because the prices of galvanized steel sheets with different production processes and different zinc layer thicknesses vary greatly, you can consult our professional staff for details and we will give you the best price and product recommendations.
Different coating thicknesses and process parameters on galvanized steel sheets affect corrosion resistance and processing performance. When selecting a galvanized steel sheet, choose the appropriate zinc coating thickness based on the specific application.
