The Next‑Generation Coated Steel
Zinc‑Aluminum‑Magnesium (ZAM) coated steel represents the pinnacle of galvanic protection. By adding 1.5‑3% magnesium to the Zn‑Al bath, CNB’s ZAM steel forms a dense, stable, and self‑healing corrosion product layer. This product outperforms GI in every measure: 5‑10x longer life in salt spray, superior cut‑edge protection, and better friction properties for stamping.

How It Works
The microstructure consists of primary zinc, Zn/MgZn₂ binary eutectic, and Zn/Al/MgZn₂ ternary eutectic. Upon corrosion, Mg²⁺ ions react to form stable Zn₅(OH)₈Cl₂·H₂O, which seals the exposed steel and prevents under‑film creep.

Key Benefits

• Self‑Healing Cut Edges: No red rust propagation from sheared edges; eliminates need for edge paint in many applications.

• Lower Friction: Stable friction coefficient 0.12‑0.14 reduces galling in stamping, extends die life.

• Wider Welding Window: 3.3kA welding lobe compared to 1.7kA for GI, reducing spatter and improving nugget quality.

• High Surface Hardness: ~120 HV vs. ~79 HV for GI, providing better scratch resistance.

Specifications

• Thickness: 0.15mm – 6.0mm

• Width: up to 1600mm

• Coating: ZM40 – ZM450

• Grades: DC51D+ZM to HC340LAD+ZM, S250GD+ZM to S550GD+ZM, DP steels