Related Knowledge of Zn-al-mg Steel Tube

1. What is Zn-al-mg Steel?

Zinc, aluminum, and magnesium are alloy metal materials that are mainly used for surface anticorrosion treatment of steel and steel products, including various zinc series coatings and overall corrosion protection of a large amount of steel. The metal originally used for surface anti-corrosion treatment of steel products was pure zinc. With the development of technology, alloy metals such as aluminum-zinc alloy and zinc-aluminum-magnesium alloy appeared one after another, and the anti-corrosion effect of the metal layer increased. Zinc-aluminum-magnesium steel coil is a new type of steel material that can be mass-produced through the existing hot-dip galvanizing process. Zinc-aluminum-magnesium steel coil has good corrosion resistance and film self-healing performance, and can adapt to various harsh environments. It is a new type of environmentally friendly and energy-saving steel coil. It can also reduce secondary corrosion protection requirements such as sealing wax and coating or It saves secondary corrosion protection costs and improves production efficiency; its forming performance is better than that of GI and GA coils, suitable for deep stamping parts manufacturing, and shortens the number of mold cleaning times; at the same time, its welding performance is also equivalent to that of GI coils, and its overall performance is even better than GA Vol.

2. What is zinc-aluminum-magnesium coating?

Zn-Al-Mg Steel Coils were originally developed to replace some stainless steel usage scenarios. Although stainless steel has good corrosion resistance, the cost is too high. Other galvanized series steel coils are not only less corrosion-resistant than stainless steel on the surface, but more importantly, it has poor protection ability for broken sections or damaged areas of the coating.

The zinc-aluminum-magnesium coating has excellent red rust resistance and self-healing anti-corrosion properties of the shear section (the initial corrosion products of the zinc-aluminum-magnesium coating will flow and cover the exposed substrate). 

Nippon Steel Corporation has launched SD coating (SuperDyma) composed of Zn-11%Al-3%Mg, which has good rust resistance, processability, weldability and paintability, and is compatible with hot-dip galvanized steel sheets and hot-dip galvanized steel sheets. Compared with galvanized-5% aluminum alloy steel plate, its plating adhesion is less but it can achieve the same corrosion resistance.

In addition, due to its good resistance to red rust, it can replace stainless steel or aluminum plates. In terms of processing performance, after bending and stretching the SD coated steel plate, the bent and stretched parts are not easy to rust, and the surface of the processed parts will not have defects, making the product more beautiful.

Moreover, ZMA coating has a denser structure, which can reduce intergranular corrosion during the corrosion process. ZMA coating has high hardness, with a Vickers hardness of 140 to 160HV, and has better resistance to scratches than ordinary pure zinc coating. Therefore, ZMA coating products can also be used in extremely harsh environments.

Zinc-aluminum-magnesium coated steel parts perfectly solve the shortcomings of ordinary coated steel parts that cannot effectively protect shear fractures, missing plating points, coating damage, etc. It can be said to be one of the coated steel parts closest to stainless steel in terms of comprehensive performance. The corrosion-resistant self-healing effect of the cut section is a major feature of zinc-aluminum-magnesium products.

Zn-al-mg Steel products are mainly used in civil construction (keel ceilings, porous plates, cable trays, earthquake-resistant brackets), agricultural and livestock production (agricultural breeding greenhouse steel structures, steel structure accessories, greenhouses, breeding equipment), railways and roads, power communications (transmission distribution high and low voltage switch cabinets, box-type substation outer bodies), automobile motors, industrial refrigeration (cooling towers, large outdoor industrial air conditioners) and other industries. The application fields are very wide.