Aluminium 5251
Scope
Aluminium 5251 is a medium strength alloy with good ductility and good formability. Alloy 5251 is known for work hardening rapidly and is readily weldable. It has a high corrosion resistance particularly in marine environments.
Application
This material is used for containers, durniture tubing, marine structures, boats, panelling and pressings, aircraft parts, silos and vehicle panels.
Supplied Forms
Sheet
Plate
Temper Types
The most common tempers for 5251 aluminium are:
H24 - Work hardened by rolling then annealed to half hard
H26 - Work hardened by rolling then annealed to three quarter hard
H22 - Work hardened by rolling then annealed to quarter hard
O - Soft.
Fabrication
Weldability - Gas: Very Good
Weldability - Arc: Very Good
Weldability - Resistance: Very Good
Brazability: Poor
Workability - Cold: Very Good
Machinability: Average
Welding
Aluminium alloy 5251 is a readily weldable alloy. The recommended filer wire is 5356 when welding alloy 5251 to itself, 6XXX series alloys, 7XXX series alloys and most other 5XXX series alloys. When welding alloy 5251 to 5005, 5020, 1XXX series or 3XXX series alloys, the recommended filler wire is 4043.
Machinability
Aluminium 5251 is readily machinable by conventional methods. It should be machined at high speed with plenty of lubrication to avoid thermal distortion of the work piece.
During machining, sharp tools are essential. High speed steel or tungsten carbide may be used as the cutting medium. The cuts must be deep and continuous with high cutting speeds.
Mills can use woodworking machinery for short runs, but inevitably, proper commercial mills are necessary for high capacity machining operations.
Heat treatment
Aluminium 5251 is annealed at 3450C. The time at this temperature and the cooling rate are not essential. Stress relief is rarely necessary but can be carried out at about 2200C. Stress relief tests should be conducted where loss of strength is a concern.
Corrosion resistance
Aluminium 5251 sheet has very good corrosion resistance. It can be used in normal, industrial and marine environments without problems. It is best suited for offshore applications.
Chemical Compositions
| Element | % Present |
|---|---|
| Manganese (Mn) | 0.1 - 0.50 |
| Iron (Fe) | 0.50 Typical |
| Copper (Cu) | 0.15 Typical |
| Magnesium (Mg) | 1.7 - 2.40 |
| Silicon (Si) | 0.40 Typical |
| Zinc (Zn) | 0.15 Typical |
| Chromium (Cr) | 0.15 Typical |
| Titanium (Ti) | 0.15 Typical |
| Aluminium (Al) | Balance |
Chemical Compositions
| Element | % Present |
|---|---|
| Manganese (Mn) | 0.1 - 0.50 |
| Iron (Fe) | 0.50 Typical |
| Copper (Cu) | 0.15 Typical |
| Magnesium (Mg) | 1.7 - 2.40 |
| Silicon (Si) | 0.40 Typical |
| Zinc (Zn) | 0.15 Typical |
| Chromium (Cr) | 0.15 Typical |
| Titanium (Ti) | 0.15 Typical |
| Aluminium (Al) | Balance |
Mechanical properties at room temperature
| Property | Value |
|---|---|
| Proof Strength | 165 MPa |
| Tensile Strength | 210 MPa |
| Elongation | 14% |
| Shear Strength | 125 MPa |
| Hardness Vickers | 65 HV |
Mechanical properties at room temperature
| Property | Value |
|---|---|
| Proof Strength | 165 MPa |
| Tensile Strength | 210 MPa |
| Elongation | 14% |
| Shear Strength | 125 MPa |
| Hardness Vickers | 65 HV |
Reference data for some physical properties (for guidance only)
| Property | Value |
|---|---|
| Density | 2.69 Kg/m3 |
| Melting Point | 625 °C |
| Thermal Expansion | 25 x 10-6 /K |
| Modulus of Elasticity | 70 GPa |
| Thermal Conductivity | 134W/m.K |
| Electrical Resistivity | 0.044 x 10-6 Ω .m |
Reference data for some physical properties (for guidance only)
| Property | Value |
|---|---|
| Density | 2.69 Kg/m3 |
| Melting Point | 625 °C |
| Thermal Expansion | 25 x 10-6 /K |
| Modulus of Elasticity | 70 GPa |
| Thermal Conductivity | 134W/m.K |
| Electrical Resistivity | 0.044 x 10-6 Ω .m |
Editor
thyssenkrupp Materials (UK) Ltd
Cox’s Lane
Cradley Heath
West Midlands
B64 5QU
Important Note
Information given in this data sheet about the condition or usability of materials respectively products are no warranty for their properties, but act as a description. The information, we give on for advice, comply to the experiences of the manufacturer as well as our own. We cannot give warranty for the results of processing and application of the products.