Aluminum circle sheets power cookware, signage, and electronics with their precise shapes. Surface defects can cause 30-50% performance loss. How we prevent scratches, oxidation, and chemical damage during storage/transport determines product lifecycle.
Three-tier protection strategy achieves 2000+ salt spray hours: pre-treatment (degreasing), coating (anodizing/spraying), and packaging (PE film). Optimal parameters include 15-25μm oxide layer thickness and >3H pencil hardness for coatings with EN 13438 & ASTM B117 certifications.
Surface integrity impacts 70% of industrial applications. Follow these methods to maintain specifications.
Why Does Surface Pre-Treatment Matter?
Improper cleaning leads to coating failure within 6 months. 65% of defects originate from contaminated surfaces.
Six-step cleaning sequence removes 99.8% contaminants: alkaline wash (pH 11, 60°C), acid etching (10% HNO3), desmutting, DI water rinsing, chrome-free conversion coating (0.5g/m²), forced drying (<5% humidity). Process validated by ISO 9227 salt spray.
Pre-Treatment Specifications
| Critical parameters for raw material preparation: | Step | Target | Equipment | QC Standard |
|---|---|---|---|---|
| Oil Removal | ≤10 mg/m² residual | Ultrasonic cleaner | ASTM D2745 | |
| Etching Depth | 1.5-3.0 μm | Spray chamber | GB/T 10125 | |
| Passivation | 30-50 mg/m² Cr-free | Dip coating | EN 12487 |
Failing at any stage reduces paint adhesion by 50-70%.
What Coating Methods Ensure Durability?
Three coating technologies dominate:
1. Anodizing (Architectural Grade)
| Parameter | Type II (Decorative) | Type III (Hardcoat) |
|---|---|---|
| Thickness | 10-15μm | 25-50μm |
| Hardness | 250-350 HV | 400-600 HV |
| Color Options | 12+ standard colors | Clear/Gray Only |
2. Powder Coating (Electrical Housing)
- Layer thickness: 60-120 μm
- Curing: 180°C × 10 mins
- Tests: 500h QUV, crosshatch ISO 2409 Class 0
Requires 0.4-0.6mm edge radius for uniform coverage.
3. PVDF Coating (Facade)
Withstands 15+ years UV exposure:
| Property | PVDF | PE Coating |
|---|---|---|
| Gloss Retention | ≥85% after 10 yrs | ≤60% after 5 yrs |
| Chalking | ASTM D4214 Class 1 | Class 3+ |
How to Handle & Store Properly?
63% of transit damage occurs from improper stacking. Key protocols:
Stacking Specifications
| Diameter Range | Max Stack Height | Interlayer Material | Environmental Control |
|---|---|---|---|
| ≤500mm | 2 meters | PE foam sheets | Temp: 10-35°C |
| 500-1200mm | 1.2 meters | Corrugated paper | Humidity: ≤60% RH |
| >1200mm | Vertical storage | Wooden separators | No direct sunlight |
Transport Protection
Use customized crates with:
- VCI paper wraps (20㎡/ton)
- 45° EPE edge protectors (density≥30kg/m³)
- Laser-etched GS1-128 traceability codes
Conclusion
Protecting aluminum circle sheets requires systematic strategies from pretreatment to logistics. Adopting chrome-free conversion coatings and PVDF layers can extend service life by 3-5×. Customized transport solutions with real-time environmental monitoring prevent 70% of handling damages while maintaining EN/ASTM compliance.
