3105 aluminum alloy is a member of the 3xxx series (aluminum-manganese alloys), known for its medium strength, good formability, and corrosion resistance. It is a non-heat-treatable alloy, meaning its properties are enhanced through cold working or strain hardening rather than heat treatment. This makes it suitable for applications requiring moderate strength and excellent ductility, such as sheet metal fabrication and general-purpose structural components.
| Property |
Value (Approximate) |
| Tensile Strength |
124–179 MPa (18,000–26,000 psi) |
| Yield Strength |
83–145 MPa (12,000–21,000 psi) |
| Elongation at Break |
8–15% |
| Hardness (Rockwell B) |
30–60 |
| Density |
~2.7 g/cm³ (0.0975 lb/in³) |
| Modulus of Elasticity |
~70 GPa (10,000 ksi) |
Strength varies with temper (e.g., H12, H14, H16, H18). Higher-numbered tempers (e.g., H18) indicate greater strain hardening and higher strength but lower ductility.
Non-heat-treatable, so strength improvements are limited compared to heat-treatable alloys like 6061 or 2024.
| Element |
Composition Range (%) |
| Aluminum (Al) |
Balance (≥97.5%) |
| Manganese (Mn) |
0.6–1.0 |
| Silicon (Si) |
≤0.30 |
| Iron (Fe) |
≤0.70 |
| Copper (Cu) |
≤0.20 |
| Zinc (Zn) |
≤0.25 |
| Other Impurities |
≤0.15 total |
Manganese (Mn) improves strength and corrosion resistance without compromising formability.
3105 is valued for its formability, corrosion resistance, and cost-effectiveness, making it suitable for:
Sheet Metal Fabrication:
Roofing, siding, and gutters in construction (due to corrosion resistance and ease of bending).
Appliance parts (e.g., washing machine drums, refrigerator panels).
General Structural Components:
Lightweight frames, brackets, and enclosures in machinery or automotive applications.
Trailer bodies and truck components.
Heat Exchangers and Radiators:
Moderate thermal conductivity and formability for non-critical heat transfer parts.
Cans and Packaging:
Occasionally used for lightweight containers or foil (though 1xxx series alloys are more common for pure aluminum packaging).
Marine Applications:
Non-load-bearing parts in boats or coastal structures due to resistance to saltwater corrosion.
Corrosion Resistance: It contains a certain amount of manganese, which can form a dense oxide film on the surface. This film effectively isolates the alloy from the external environment, making it highly resistant to atmospheric and seawater corrosion. It can maintain good performance in many corrosive media, suitable for applications in coastal areas and some chemical environments.
Formability: With good plasticity in the annealed state, 3105 aluminum alloy has moderate plasticity in the semi - cold - worked hardened state. It can be easily processed by various methods such as deep - drawing, bending, and shaping, and can be made into various complex - shaped parts, meeting the processing requirements of different products.
Weldability: It has excellent weldability and can be welded by conventional TIG, MIG, and arc welding methods. The welded joint has good strength and tightness, which is convenient for manufacturing various structural parts or devices and is conducive to improving production efficiency and product quality.
