What is Zinc Aluminum Magnesium Coating?

The types of metal coatings we use in our daily processing are: pure zinc (+Z), aluminum-zinc (+AZ), and zinc-aluminum-magnesium (+AZM/AM). Different hot-dip coated steel materials have various characteristics:

Pure Zinc Coating

The zinc content in the hot-dip galvanizing pot is no less than 99%, making it a relatively economical type of corrosion-resistant coating.

Pure zinc coated steel plates are divided into two types: those without zinc flowers and those with zinc flowers, with their corrosion resistance almost identical. If painting or varnishing is required later, the zinc-free flower products will be more aesthetically pleasing; while thick zinc layer products are usually predominantly with flowers (e.g., zinc layer weight of both sides 275g/m2).

Aluminum-Zinc Coating

The electrolyte contains approximately 55% aluminum, about 1.6% silicon, with the remaining components being zinc. Aluminum-zinc coatings have higher corrosion resistance than pure zinc coatings in most environments, and steel coils with zinc flowers are used. A good steel mill can produce uniformly beautiful zinc flowers, suitable for direct use in household appliances. However, aluminum-zinc coatings do have some drawbacks.

The welding performance of aluminum-zinc coated steel plates is inferior to that of pure zinc, especially when using resistance welding, as the molten coating metal tends to adhere to the electrode tips. Since the adhered metal becomes harder upon melting, the efficiency of removing it with ordinary grinding tools is very low, which can lead to electrode tip failure. Therefore, it is advisable to minimize the welding process during use.

Additionally, the protective effect of the aluminum-zinc coating on the steel plate cutting edges is far inferior to that of pure zinc coating, let alone the zinc-aluminum-magnesium coating. Proper corrosion prevention measures for the cutting edges are necessary (such as painting and sealing).

Section 3: Zinc-Aluminum-Magnesium Coating

The initial development of zinc-aluminum-magnesium coated steel plates was to replace certain usage scenarios of stainless steel, which, while having good corrosion resistance, is overly expensive; whereas other galvanized steel plate series, in addition to being less corrosion-resistant on the surface than stainless steel, are more critically lacking in protective capabilities for断面 or coating damage areas.

The zinc-aluminum-magnesium coating boasts excellent resistance to red rust and self-healing corrosion properties on the shear cross-section (the initial corrosion products of the zinc-aluminum-magnesium coating flow and cover the substrate), and it also exhibits significantly superior welding performance compared to galvanized steel with aluminum-zinc coating.

Zinc-aluminum-magnesium coated steel components have perfectly addressed the shortcomings of ordinary coated steel components, which cannot effectively protect cut edges, areas with incomplete coating, and damaged coatings. They can be said to be one of the coated steel components that come closest to stainless steel in terms of comprehensive performance. The self-healing corrosion resistance of the cut section is a major feature of the product.

Our products are primarily used in various industries, including civil engineering (such as joist ceilings, perforated plates, cable trays, and seismic support brackets), agriculture and animal husbandry (including agricultural breeding greenhouses, steel structures, greenhouse components, and feeding equipment), railway and road construction, electricity and communication (high and low-voltage switchgear and outdoor box-type substations), automotive motors, and industrial refrigeration (cooling towers and large outdoor industrial air conditioners), covering a wide range of applications.