Aluminium alloy 5251 is a medium-strength aluminium–magnesium alloy offering good ductility and excellent formability. It work-hardens rapidly, making it well suited to forming and pressing operations while maintaining dependable structural performance. Alloy 5251 is readily weldable and provides high corrosion resistance, particularly in marine and coastal environments, making it a reliable choice for a wide range of structural and decorative applications. The mechanical properties listed below apply to the H24 temper. Properties for other tempers are available separately.
Alloy 5251-H24 is typically used in:
Alloy 5251-H24
Spec: BS EN 573-3:2009
| Chemical Element | % Present |
|---|---|
| Manganese (Mn) | 0.10 – 0.50 |
| Iron (Fe) | 0.00 – 0.50 |
| Copper (Cu) | 0.00 – 0.15 |
| Magnesium (Mg) | 1.70 – 2.40 |
| Silicon (Si) | 0.00 – 0.40 |
| Zinc (Zn) | 0.00 – 0.15 |
| Chromium (Cr) | 0.00 – 0.15 |
| Aluminium (Al) | Balance |
| Other (Each) | 0.00 – 0.05 |
| Other (Total) | 0.00 – 0.15 |
| Property | Value |
|---|---|
| Density | 2.69 g/cm³ |
| Melting Point | 625 °C |
| Thermal Expansion | 25 × 10⁻⁶ /K |
| Modulus of Elasticity | 70 GPa |
| Thermal Conductivity | 134 W/m·K |
| Electrical Resistivity | 0.044 × 10⁻⁶ Ω·m |
Spec: BS EN 485-2:2008
| Property | Value |
|---|---|
| Proof Stress | ≥ 140 MPa |
| Tensile Strength | 210 – 250 MPa |
| Hardness (Brinell) | 62 HB |
Aluminium alloy 5251 corresponds to the following designations (not direct equivalents):
The most commonly supplied tempers for aluminium alloy 5251 include:
Aluminium alloy 5251 is readily weldable. Recommended filler wire: 5356 when welding 5251 to itself, most 5XXX alloys, and 6XXX or 7XXX series alloys. 4043 when welding to 5005, 5020, 1XXX series, or 3XXX series alloys.
| Property | Rating |
|---|---|
| Weldability – Gas | Very Good |
| Weldability – Arc | Very Good |
| Weldability – Resistance | Very Good |
| Brazability | Poor |
| Property | Rating |
|---|---|
| Cold Workability | Very Good |
| Machinability | Average |
