Magnelis is a type of metal coating technology used to protect steel sheets against corrosion.
It generally refers to steel coated with a zinc-aluminum-magnesium (Zn-Al-Mg) alloy. Magnelis® is a registered product brand developed by ArcelorMittal.
Key Features of Magnelis
- Coating: A zinc-based alloy containing approximately 3% magnesium and 3.5% aluminum.
- Corrosion resistance: Provides significantly higher corrosion resistance compared with conventional galvanized steel.
- Cut edges and welded areas: The coating can provide a self-healing effect, helping to protect exposed areas.
- High corrosion performance can be achieved with a relatively thin coating layer.
- It is particularly suitable for outdoor applications, agriculture, energy, construction, and steel structures.
For example, Magnelis-coated steel is commonly used for roof substructures, solar panel mounting systems, cable trays, agricultural structures, and steel profiles.
Unique Chemical Structure and Features
The key distinction separating Magnelis from standard galvanized steel is its alloy composition. The coating bath consists of 93.5% Zinc (Zn), 3.5% Aluminum (Al), and 3.0% Magnesium (Mg). The addition of magnesium forms a highly stable protective layer on the surface, elevating corrosion resistance to top levels.
- Self-Healing: A magnesium-based protective film forms spontaneously on cut, drilled, or bent edges, covering the exposed steel and preventing rust formation.
- Surface Treatments: Excellent processability and an aesthetic dark gray appearance are achieved through optional E-passivation, Easyfilm, or Oiling applications.
Superior Performance Proven by Tests
Salt spray and corrosion tests conducted in laboratory environments have proven that Magnelis is, on average, up to 3 times more durable than standard galvanized steel:
- Salt Spray Test: While a 20 µm standard galvanized coating rusted within 6 weeks, a 20 µm Magnelis coating maintained full protection against corrosion for 34 weeks.
- Batch Galvanizing Comparison: While 85 µm thick batch-galvanized steel corroded within 12 weeks, 20 µm Magnelis sustained its protection after 12 weeks.
Design Lifespan Exceeding 50 Years (ISO 12944-2)
According to ISO 12944-2 standards, the expected coating design lifespan of Magnelis products (ZM310, ZM430, ZM620) exceeds 50 years:
| Corrosion Category (ISO 12944-2) | ZM310 (25 µm) | ZM430 (35 µm) | ZM620 (50 µm) |
| C2 (Low Risk) | > 50 Years | > 50 Years | > 50 Years |
| C3 (Medium Risk) | 30 – 50+ Years | 40 – 50+ Years | > 50 Years |
| C4 (High Risk) | 15 – 30 Years | 20 – 40 Years | 30 – 50+ Years |
| C5 (Very High – Marine/Industrial) | 8 – 15 Years | 10 – 20 Years | 15 – 30 Years |