Galvanized steel sheets with zinc-aluminum-magnesium coating represent a new type of highly corrosion-resistant steel plate featuring a ternary alloy coating composed of zinc (Zn), aluminum (Al), and magnesium (Mg) applied to the steel surface. They can be regarded as an upgraded iteration of traditional hot-dip galvanized steel sheets.
Zinc-Aluminum-Magnesium Coated Steel Classification & Standards
1. Classification by Aluminum Content
| Type | Al Content | Mg Content | Features & Applications |
|---|---|---|---|
| Low-Aluminum | 1–3% | 1–3% | Excellent formability, corrosion resistance significantly better than galvanized steel. Widely used in automotive parts and precision electronic equipment. |
| Medium-Aluminum | 5–11% | 2–4% | Most widely applied with the best overall performance. Outstanding cut-edge corrosion resistance. Commonly used for PV brackets, highway guardrails, and building keels. |
| High-Aluminum | 55% | 1–2% | High temperature resistance, high reflectivity, bright appearance. Suitable for building roofs, home appliance backplates, and high-temperature components. |
2. Common Grades & Standards
| Standard System | Common Grades | Description |
|---|---|---|
| China GB/T | S250GD+ZM S350GD+ZM DX51D+ZM | Based on original galvanized grades, suffix changed from Z to ZM for zinc-aluminum-magnesium coating. |
| Europe EN | DX51D+ZM DX52D+ZM S350GD+ZM | Similar to Chinese standard; ZM is the universal suffix for zinc-aluminum-magnesium. |
| US ASTM | A1046 A1063 | Covers requirements for zinc-aluminum-magnesium coatings. |
