3A21 aluminum coil is an aluminum–manganese alloy in the 3000 series. It is known for its good corrosion resistance, excellent formability, and moderate strength, making it suitable for a variety of applications in construction, transportation, and general engineering. 3A21 is widely used in environments requiring good durability and easy fabrication.
Description
Yutwin New Materials specializes in the production of aluminum coils and sheets in a wide range of alloys, grades, and specifications, offering stable quality, flexible customization, and reliable supply to meet the diverse needs of different industries.
Features
- Aluminum–manganese–magnesium alloy (Al–Mn–Mg)
Belongs to the 3xxx-series aluminum alloys, with manganese and magnesium as main alloying elements, offering higher strength than 3xxx-series Al–Mn alloys.
- Medium to high mechanical strength
Stronger than 3003 and 3105, suitable for structural, load-bearing, and automotive body applications.
- Excellent corrosion resistance
Performs well in atmospheric, marine, and industrial environments, ideal for outdoor, automotive, and coastal applications.
- Good formability and workability
Can be rolled, bent, stamped, and deep-drawn, suitable for medium to thin-gauge processing and complex shapes.
- Good thermal and electrical conductivity
Supports heat dissipation and moderate electrical applications.
- Smooth and uniform surface finish
Suitable for anodizing, painting, coating, embossing, or film lamination for both decorative and functional purposes.
- Good weldability
Compatible with TIG, MIG, and spot welding for reliable joints.
- Lightweight material
Low density supports weight reduction while maintaining durability and mechanical performance.
Specifications
| Item | Specification |
|---|---|
| Alloy / Grade | 3A21 |
| Chemical Composition (%) | Al ≥ 96.8, Mn 0.8–1.5, Fe ≤ 0.7, Si ≤ 0.6, Cu ≤ 0.1, Mg ≤ 0.1, Zn ≤ 0.2, Ti ≤ 0.15, Others ≤ 0.05 |
| Series | 3000 Series (Al-Mn Alloy) |
| Temper | O, H14, H16, H18, H19, H22 |
| Thickness (mm) | 0.2 – 250 |
| Width (mm) | 100 – 2650 |
| Length (mm) | 1000 – 12000 (Customizable) |
| Surface Finish | Mill Finish, Anodized, Painted |
| Standard | GB/T 3880, ASTM B209, EN AW-3A21 |
Common Aluminum Surface Treatments
Polishing
Polishing uses mechanical grinding, chemical, or electrochemical methods to improve the smoothness and brightness of aluminum surfaces. Polished aluminum features a high-gloss finish and excellent decorative appearance.
Brushing
Brushing is a surface treatment process that creates fine, directional textures on aluminum using abrasive belts or brushes. The brushed surface provides a refined metallic appearance while helping conceal minor scratches.
Coating
Coating applies a protective coating onto the aluminum surface through powder coating, liquid spraying, or other coating methods. It provides excellent weather resistance, corrosion protection, and a wide range of color options. Coated aluminum offers both decorative appeal and long-term durabilit.
Anodizing
Anodizing is an electrochemical process that forms a dense oxide layer on the aluminum surface, improving corrosion resistance, wear resistance, and surface hardness. The oxide layer can also be colored to achieve various finishes.
Sand Blasting
Sand blasting uses high-speed abrasive particles to impact the aluminum surface, creating a uniform matte texture. This process provides a soft metallic appearance, reduces fingerprint marks, and improves coating adhesion for subsequent finishing processes.
Embossing
Embossing is a process that forms raised or recessed patterns on aluminum surfaces through rolling or stamping. Common patterns include stucco, diamond, and wood grain textures. Embossed aluminum offers excellent decorative effects, scratch resistance, and certain anti-slip properties.
Applications
- Automotive body panels
Widely used in car doors, roofs, hoods, and other vehicle body components due to good strength, corrosion resistance, and lightweight properties.
- Architectural and building applications
Suitable for roofing, wall cladding, ceiling panels, and decorative sheets in both interior and exterior environments.
- Transportation and railway components
Applied in truck panels, train interiors, and other lightweight transport structures where medium-to-high strength and corrosion resistance are required.
- Heat transfer and thermal applications
Used in heat exchangers, cooling fins, and other components requiring effective thermal conductivity.
- Chemical and industrial equipment
Suitable for tanks, containers, covers, and protective panels in mild chemical and industrial environments.
- General fabrication and forming
Ideal for stamping, bending, rolling, and deep-drawing of medium-thickness sheets and structural or decorative components.
