What is hot-dip galvanized aluminum-magnesium coated plate? What are the characteristics and differences of hot-dip galvanized aluminum-magnesium coated plate?

What is zinc-aluminum-magnesium coating?

According to the definition of European standard EN10346-2015, zinc-aluminum-magnesium coating is a ternary alloy coating whose main component is zinc, and the content of aluminum and magnesium is between 1.5% and 8% (the content of magnesium is not less than 0.2%).

Why is the aluminum-magnesium ratio specified in the European standard for zinc-aluminum-magnesium coating a range of 1.5-8%, rather than a fixed value of 55% aluminum content in aluminum-zinc coating?

This is because we applied for trademarks and patents after investing a lot of R&D funds in developing new products, so we adjusted the composition to avoid patents, which also led to slight differences in the composition ratio of zinc-aluminum-magnesium coatings from different manufacturers. These products with slightly adjusted coating composition are usually considered to be “zinc-aluminum-magnesium coated steel plates”, so the European standard set a range in order to “take the overall situation into consideration” when revising the version.

Advantages of aluminum-magnesium-zinc plate

1. Good corrosion resistance: The base material and surface coating of the plate have strong corrosion resistance. The high-strength magnesium-aluminum-zinc alloy is used as the coating, and its corrosion resistance far exceeds that of traditional steel plate materials.
2. High strength: Aluminum-magnesium-zinc plate has excellent resistance to strong winds, earthquakes, and heavy pressure. It is lighter than traditional steel plate materials, but has higher strength and rigidity.
3. Beautiful and durable: The material and even the color of the plate are very flat, and the surface coating has excellent color stability and gloss, which greatly extends the service life.
4. Safety: The plate has a very high fire rating and safety performance, which can prevent fires to a great extent.
5. Convenient construction: Compared with traditional steel plate materials, aluminum-magnesium-zinc plate is lighter, convenient for construction, reduces construction period, and reduces manpower and material costs.

Classification of zinc-aluminum-magnesium coatings

• (1) Low aluminum zinc-aluminum-magnesium coatings, aluminum content: 1-3.5%. This coating is formed by adding a certain amount of aluminum, magnesium and other elements to hot-dip galvanizing.
• (2) Medium aluminum zinc-aluminum-magnesium coatings, aluminum content: 5~11%.
• (3) High aluminum zinc-aluminum-magnesium coatings, aluminum content: 55%. This coating is formed by adding a certain amount of magnesium and other elements to hot-dip aluminum zinc.

The future market of zinc-aluminum-magnesium composite steel plate

(1) Highway guardrails

For a long time, the production process of highway guardrails in China has been batch galvanizing, which has low production efficiency and high production costs. On May 15, 2015, the General Administration of Quality Supervision, Inspection and Quarantine and the Standardization Administration of China jointly issued the new national standard GB/T 31447-2015[14] “Pre-galvanized Highway Guardrails”, which came into effect in August of the same year. After the release of the new standard, zinc-aluminum-magnesium composite steel plates can be used in the manufacture of highway guardrails in China.

(2) Automobiles

The production of zinc-aluminum-magnesium composite steel plates is more difficult than that of pure zinc coatings, mainly manifested in increased oxidation on the surface of the plating solution and increased surface defects of the coating. In the future, the production of zinc-aluminum-magnesium composite steel plates on automobile plates will be full of challenges. Low-aluminum-magnesium zinc-aluminum-magnesium products are gradually being used in automobiles due to their corrosion resistance and high surface quality. Domestic automobile companies such as BMW, Great Wall, Dongfeng, and GAC are all conducting certification work for zinc-aluminum-magnesium products. Some automobile companies have already conducted small-scale trials and are expected to use such zinc-aluminum-magnesium products on a large scale in the future.

(3) Home appliances

Home appliance companies led by Haier and Midea have conducted laboratory certification, small-scale trials of materials and sample rolls on the products of Baosteel, Shougang Jingtang and Hegang Tangshan. They are expected to be widely promoted under the condition of subsequent cost reduction, especially for applications with high corrosion resistance requirements such as air conditioners, washing machines, microwave ovens and gas hoods.

(4) Color-coated plates

Color-coated plates with zinc-aluminum-magnesium products as substrates are well-known for their energy saving and excellent corrosion resistance. Color-coated plates as substrates account for 60% of Thyssen zinc-aluminum-magnesium products in Europe, which reduces zinc consumption by 1/3 compared with galvanized products and are widely used in construction and home appliances. In the future, the use of color-coated plates with zinc-aluminum-magnesium products as substrates will have a large room for improvement.

(5) Photovoltaic and solar thermal

The National Development and Reform Commission, the National Energy Administration and the Ministry of Finance have issued various notices and measures to encourage and support solar power generation. In view of the harsh environment of deserts, tidal flats and Gobi where photovoltaic power stations are located, thermal-based zinc-aluminum-magnesium materials with excellent corrosion resistance are expected to be widely used in the production of photovoltaic brackets.