Aluminum Alloy 5059 is a high-strength, marine-grade aluminum alloy primarily used in shipbuilding, automotive, aerospace, and defense industries. It belongs to the 5xxx series aluminum alloys, which are aluminum–magnesium alloys known for excellent corrosion resistance, especially in marine environments.
Key highlights:
High corrosion resistance, particularly against seawater.
Good weldability.
High tensile strength in heat-treated and cold-worked conditions.
Resistant to stress corrosion cracking.
Chemical Composition of Aluminum Alloy 5059
| Element | Typical Composition (%) |
|---|---|
| Magnesium (Mg) | 5.0 – 5.9 |
| Manganese (Mn) | 0.5 – 1.0 |
| Chromium (Cr) | 0.3 – 0.7 |
| Zinc (Zn) | ≤0.3 |
| Copper (Cu) | ≤0.4 |
| Iron (Fe) | ≤0.5 |
| Silicon (Si) | ≤0.5 |
| Titanium (Ti) | ≤0.2 |
| Aluminum (Al) | Balance (~90.5 – 94%) |
Notes:
The relatively high magnesium content contributes to superior corrosion resistance and strength.
Small additions of chromium improve toughness and help prevent grain growth during heat treatment.
Mechanical Properties
| Property | Typical Value (T6 or Cold-Worked Condition) |
|---|---|
| Ultimate Tensile Strength | 310 – 350 MPa (45 – 51 ksi) |
| Yield Strength | 210 – 250 MPa (30 – 36 ksi) |
| Elongation at Break | 10 – 18% |
| Hardness (Brinell) | 90 – 100 HB |
| Density | 2.68 g/cm³ |
Features:
High strength-to-weight ratio.
Excellent fatigue resistance.
Non-heat-treatable (strength comes from cold working).
Maintains strength in sub-zero temperatures.
Corrosion Resistance
Exceptional resistance to marine corrosion (seawater).
Resistant to stress corrosion cracking and pitting.
Suitable for environments with high humidity or salt spray.
Applications of Aluminum Alloy 5059
Shipbuilding & Marine
Hulls of boats and ships
Superstructures
Yachts and naval vessels
Defense & Aerospace
Armored vehicles
Aircraft parts
Automotive & Transportation
Truck bodies and trailers
Railway vehicles
Other
Pressure vessels
Cryogenic containers
Standards and Specifications
Aluminum Alloy 5059 is standardized under multiple global norms:
| Standard | Description |
|---|---|
| ASTM B209 | Aluminum and Aluminum-Alloy Sheet and Plate |
| EN 485-2 / EN 573-3 | European standards for chemical composition and mechanical properties |
| AA 5059 | Aluminum Association designation |
| ISO 6361 | Wrought aluminum and aluminum alloy sheets, strips, and plates |
Welding and Fabrication
Weldability: Excellent using MIG/TIG methods.
Forming: Can be cold-formed; not suitable for extensive hot working.
Heat Treatment: Non-heat-treatable; properties depend on cold working and temper (H116, H321 are common for marine applications).
Typical Tempers
H116: Stress corrosion resistant; used in marine environments.
H321: Stabilized temper for high-strength applications.
H112: General-purpose, non-heat-treatable.
