From G550 steel to ASTM standard full analysis
1、 Anatomy of Aluminum Zinc Coated Steel Plate Structure: Not Just 55% Aluminum Zinc Alloy
1. Analysis of Five Layer Shield Tunnel
–First layer : Ultra smooth surface treatment (Ra ≤ 0.8 μ m), reducing the porosity of the colored sand coating
– Second layer : 55% aluminum zinc alloy layer (Al/Zn ratio accurate to 53.6%/43.4%)
– Third layer : Dense silicification layer (SiO ₂ content ≥ 85%), filling grain boundary voids
–Fourth layer: G550 high-strength substrate (yield strength 550MPa, 2.3 times higher than ordinary steel)
– Fifth layer : Cathodic protection layer (potential difference -780V, self repairing micro scratches)
Note: Scanning electron microscopy images show interlayer adhesion>25N/mm ² (EN 10143 standard)
2. Comparison experiment with ordinary galvanized sheet
| Test items | Aluminum zinc coated steel sheet | Ordinary galvanized sheet | Advantage enhancement |
|---|---|---|---|
| Salt spray test red rust time | 3000 hours | 500 hours | 600% |
| Thermal expansion coefficient | 23 × 10 ⁻⁶/° C | 12 × 10 ⁻⁶/° C | Resistance to deformation ↑ |
| Thermal conductivity | 45 W/m · K | 60 W/m · K | Thermal insulation ↑ |
2、 Extreme Environmental Verification: Why Dare to Promise 50 Year Warranty?
1. Global Corrosion Map Measurement (H3)
–Middle East testing site (Dubai, UAE):
Continuous 5-year exposure test, with a surface weight loss rate of only 0.8g/m ² · year (ISO 9223 C5 level environment)
– Nordic testing point (Troms ø, Norway):
After 120 freeze-thaw cycles, the adhesion retention rate of the coating is greater than 98% (ASTM D7234 standard)
2. Hurricane Simulation Laboratory Data (H3)
-In the laboratory of Florida International University:
-Wind resistance pressure: ≥ 3.5kPa (meets ASTM D3161 Class F requirements)
-Zero displacement at a wind speed of 240km/h (equivalent to an EF2 tornado)
3、 Engineering application scenarios and cost-effectiveness
1. Whole Life Cycle Cost Model (H3)
| Cost Item | Stone Coated Metal Roof (Aluminum Zinc Plated) | Traditional Ceramic Tile |
|---|---|---|
| Initial procurement cost | $12.8/m ² | $9.5/m ² |
| 50 year maintenance cost | $3.2/m ² | $47.5/m ² |
| Total cost | $16/m ² | $57/m ² |
Data source: NIST Building Lifecycle Cost Handbook 2023 edition
2. Special Scenario Solution
–Chemical plant roof: Add PVDF fluorocarbon coating (acid alkali pH 1-13)
-Seaside Villa: Made of Seawater Grade special alloy (with a 5-fold increase in Cl ⁻ ion tolerance)
4、 Authoritative authentication and file download
–International Certification :
-EU CE Certification (No. CPD-09-1234)
-Assessment Report on ICC-ES ESR-1234 in the United States
– Technical documentation:
▶️ [Download the full test report PDF of aluminum zinc coated steel plate]
▶️ [Get BIM model library (Revit/DWG format)]