What is a galvanized plate?

Galvanized plate is a metal material with a layer of zinc coated on the surface of steel sheet, mainly used for rust prevention and prolonging service life. The zinc layer effectively insulates air and moisture and prevents steel sheets from rusting, so it is widely used in construction, home appliances, automobile manufacturing and other fields. The following is a detailed introduction to galvanized plate.

1.Classification of Galvanized Plate 

Galvanized plate is mainly classified into two kinds of hot-dip galvanized plate and electric galvanized plate according to different production processes.

Hot-dip galvanized plate: The steel plate is immersed in molten zinc liquid, so that the zinc layer is combined with the surface of the steel plate. The zinc layer formed by this process is thicker and has a strong anti-rust capability, which is suitable for outdoor environments or scenarios that require high corrosion resistance, such as building roofs and bridge structures.

-Electro galvanized plate: A zinc layer is deposited on the surface of the steel sheet by electrolysis. The zinc layer of this process is thinner and the surface is smoother, which is suitable for products with higher requirements on surface quality, such as appliance shells and automobile parts.

2. Advantages and performance characteristics of galvanized plate 

(1) Excellent corrosion resistance

-The zinc layer can effectively block oxygen and moisture, reducing the risk of steel corrosion.

According to the American Galvanizing Association (AGA), the service life of hot-dip galvanized steel can reach 50-100 years under ordinary atmospheric conditions, far exceeding the 5-10 years of ordinary steel.

(2) Moderate cost, cost-effective

-While the initial cost of galvanized steel is about 10-20% higher than that of ordinary carbon steel, its later maintenance cost is extremely low.

-Taking bridges as an example, the use of galvanized steel can reduce painting maintenance costs by 90% (Source: International Zinc Association).

(3) Good processing adaptability

-It can be stamped, bent, welded, etc. to meet different manufacturing needs.

Note that the melting point of the zinc layer is about 420℃, so avoid high-temperature damage when welding.

(4) Beautiful appearance and various functions

The surface of hot-dip galvanized zinc has a silver-gray “zinc flower” texture, while electro-galvanized zinc is smoother.

Through the passivation process, decorative coatings such as blue-white and green-yellow can also be obtained.

(5) Environmentally friendly and recyclable

Zinc can be 100% recycled and used galvanized plates can be re-melted to reduce waste of resources.

-EU research shows that the carbon emissions of galvanized steel are 60% lower than stainless steel (European Steel Technology Platform report).

(6) Improved mechanical properties

-The galvanized layer increases the wear resistance and hardness of the steel sheet.

-According to the GB/T 2518-2019 standard, the tensile strength of hot-dip galvanized steel sheet can reach 270-500MPa, which can meet the structural strength and take into account the processing needs.

3. Application fields of galvanized plate 

The application range of galvanized plate is extremely wide, covering almost all aspects of people's daily life and industrial production:

(1) Construction industry

-For roofs, curtain walls, steel frames, ventilation ducts, etc.

-Hot-dip galvanized steel sheet can be used for a long time in coastal and high humidity areas due to its weather resistance.

(2) Home Appliance Industry

-Refrigerators, washing machines, air conditioning shells often use electric galvanized plate, not only anti-rust, but also easy to paint and aesthetic treatment.

(3) Automobile industry

-Electro-galvanized plate is commonly used for automobile body and chassis parts to resist corrosion from rain, mud and salt spray.

-According to the China Association of Automobile Manufacturers (CAAM) 2023 report, more than 70% of domestic car body sheets are made of galvanized steel.

(4) Agricultural facilities

-Applied in greenhouses, grain silos, and water conservancy equipment due to its corrosion resistance and low maintenance cost.

(5) Power and Transportation

-Hot-dip galvanized steel is commonly used in power transmission towers, highway guardrails, and rail transportation infrastructure.

4. Production process of galvanized plate 

The production of galvanized plate mainly includes the following steps:

-Pre-treatment of steel plate: Remove the oxidized layer and impurities on the surface of steel plate through pickling to ensure that the zinc layer can be firmly adhered.

-Galvanization: Depending on the process, hot dip or electroplating is used to form the zinc layer.

Post-treatment: Some galvanized steel sheets will be passivated or oiled to further enhance rust resistance or improve surface quality.

5.Quality standards of galvanized plate 

(1) In actual production and procurement, galvanized plate needs to meet a series of quality standards:.

-GB/T 2518-2019 Continuous hot-dip galvanized steel sheet and strip.

-ASTM A653 (American Standard).

-EN 10346 (European Standard)

(2) Key testing indicators include.

-Zinc layer weight (g/m): the higher the value, the stronger the anti-corrosion ability.

-Surface quality: there shall be no scratches, bubbles, plating off.

-Mechanical properties: tensile strength, elongation, etc. to meet the standard requirements.

6. Suggestions for purchasing galvanized plate

Selection according to the use: outdoor construction is recommended to choose hot-dip galvanized plate, home appliances or precision parts can choose electric galvanized plate.

-Pay attention to the thickness of the zinc layer: for occasions with high rust prevention requirements, choose products with a thicker zinc layer.

-Check the surface quality: avoid products with obvious scratches or unevenness.

-Refer to the price: the price of galvanized plate varies greatly with different processes and specifications, so you need to choose in accordance with your budget and needs.

7. Maintenance and storage of galvanized plates

-Avoid scratches: Care should be taken when handling and processing to prevent the zinc layer from breaking and affecting the rust prevention effect.

-Dry storage: Galvanized plates should be stored in a dry and ventilated environment to avoid moisture causing oxidation of the zinc layer.

-Regular inspection: Galvanized plates used for a long period of time should be inspected regularly for the condition of the zinc layer and repainted or replaced if necessary.

8.Environmental protection of galvanized plate

Galvanized plate not only has excellent anti-corrosion properties, but also in line with the direction of green development:.

(1) Resource recycling: Waste galvanized plate can be recycled and reused, reducing the pressure of raw material mining.

(2) Low-carbon manufacturing: A new generation of galvanizing process is transforming to low energy consumption and low emissions.

(3) Functionality Expansion: In the future, galvanized plate may be combined with photovoltaic modules, anti-fouling coatings, etc., to become a multifunctional building material.

Overall, galvanized plate has become an indispensable and important material in the global steel industry chain by virtue of its superior anti-corrosion performance, moderate cost and wide range of applications. From construction to automobile, from home appliances to agriculture, it is everywhere. With the promotion of green manufacturing and industrial upgrading, galvanized plate will play an even more critical role in the future.

For consumers, choosing the right type of galvanized plate, combined with scientific use and maintenance, can not only extend product life, but also reduce maintenance costs, and achieve a win-win situation in terms of economic and environmental benefits.