What Is ZAM Steel?

ZAM steel refers to zinc aluminum magnesium steel, and its coating consists of Zn, Al, and Mg. Adding Al and Mg contents offers much better corrosion resistance, several times to ten times higher than that of GI and GL steel. In addition, zinc magnesium aluminum coating has excellent processing performance and great hardness. And it also has a great self-healing effect on the cutting area. Because of its superior corrosion resistance, ZAM steel products are widely used in construction (roofing and wall), steel structures and accessories, railways, bridges, agriculture and animal husbandry (greenhouses, livestock farms, etc.), home appliances, automobiles, color-coated substrates, etc.

Advantages of ZAM Steel

1. Superior corrosion resistance;

2. Great self-healing performance;

3. Excellent scratch corrosion resistance;

4. Excellent workability.

Brands of Zinc Aluminum Magnesium Steel

1. ZAM®

ZAM® is a brand from Nippon Steel. It is a kind of highly corrosion-resistant zinc-aluminum-magnesium alloy coated steel. The coating consists of 6% aluminum, 3% magnesium, and zinc. It has longer service life than other coated products. Aluminum and magnesium provide superior corrosion resistance so it is a great alternative to stainless steel and aluminum.

2. SUPERDYMA®

SUPERDYMA® is a brand of BlueScope. Its coating is made of zinc, 11% aluminum, 3% magnesium, and 0.25% silicon. When the red rust occurs at the exposed cutting surface, the coating around the cutting will dissolve and form a dense protective film, including zinc hydroxide, alkaline zinc chloride, and magnesium hydroxide. After several months, the cut part will be completely covered. Adding silicon aims to improve the ability to resist white rust and improve the processability of the coating. Therefore, it has high corrosion resistance even in corrosive environments.

3. BZM and BAM

BZM is a brand of Baosteel, referring to low-aluminum ZAM coating, with an aluminum content of 1-3.5%. It is an upgrade product of GI. And there is another brand, namely BAM, which is an upgrade of GL. It refers to high-aluminum ZAM coating, which contains 55% aluminum. The high magnesium or high aluminum coating is relatively brittle, but it is more corrosion-resistant. During the salt spray test, its service life can reach 4,000 hours. But after bending, there will be cracks. While low aluminum and low magnesium coating have good flexibility, which is more suitable for bending, stamping, and other processing. Besides, the salt spray test can reach 3,300 hours, which is the most cost-effective product in the market.

4. Guanzhou Company from China also offers a kind of ZAM steel, which adds 2% magnesium on the basis of zinc and aluminum coating, which has excellent corrosion resistance and protection performance of the cut area.

Role of Al, Mg, and Si

The zinc-aluminum-magnesium coating is a kind of alloy coating. The main component is zinc, and the content of aluminum and magnesium is between 1.5 and 8%, of which the magnesium content is not less than 0.2%. Here let’s review the role of different elements.

Al: Improve the resistance to corrosion and heat; inhibit the reaction between the zinc and iron; thin the Fe-Zn compound layer and inhibit the oxidation of magnesium;

Mg: Improve the corrosion resistance; reduce the surface tension of the coating;

Si: Inhibit the reaction of aluminum and iron; reduce the compound layer between the coating and the substrate; improve the processing performance.

Below is a table showing the hardness of different coatings.

Coating Types	Hardness
ZAM	140Hv-160Hv
GL (55% Al-Zn)	100Hv-110Hv
Galfan (5% AL-Zn)	80Hv-100Hv
GI (pure zinc coating)	55Hv-65Hv

Uses of Different ZAM Coated Steel

Coating Types	Uses
Zn, 1. 5% Al, 1. 5% Mg	Automotive outer panels and inner panels, structural parts, home appliance outer panels
Zn, 2% Al, 2% Mg	Outer panels of large air conditioners, color-coated substrate, home appliance inner panels
Zn, 6% Al, 3% Mg	Building exterior screens, sound barriers, guardrails, photovoltaic brackets

Conclusion

Wanzhi Steel also offers zinc-aluminum-magnesium coated steel, which is made through the hot-dip galvanizing process. The ZAM coating added Al, Mg, and Si contents, which offers superior corrosion resistance. The coating has good ductility, and it will not be damaged during the bending process.  Thus, it is widely used in construction, road protection, three-dimensional parking lots, steel structure, keel ceilings, perforated panels, cable trays, etc. At Wanzhi Steel, we also have color coated steel with ZAM steel as the base metal. Welcome to contact us for more information!