Machining
Fair. The alloy is gummy in O temper; H112 machines better. Use sharp, polished carbide tools, high positive rake and generous coolant.
Aerospace · High-magnesium bar
5A06 Aircraft Aluminium Bars
5A06 is a Chinese-standard aluminium alloy with about 6.3 % magnesium, the highest in common use, giving the strongest non-heat-treatable bar available. Formerly called LF6 and close to the Russian AMg6, it is used for welded tank fittings, rocket and launch-vehicle ground structures and corrosion-exposed hardware. Metline supplies 5A06 round, square, hexagon and flat bar in O, H112 and F to GB/T 3191, worldwide.
- Alloy
- 5A06 (Al-6.3Mg-0.65Mn)
- Tempers
- O, H112, F
- Diameter
- About 5 – 300 mm
- Standards
- GB/T 3190 · GB/T 3191
Why 5A06 is used in aerospace
Most western 5xxx alloys stop at about 5 % magnesium. 5A06 goes to 5.8 – 6.8 %, which raises tensile strength to roughly that of 6061-T4 in a weldable alloy that needs no heat treatment. The alloy has a long history in Soviet-pattern and Chinese aerospace programmes as AMg6 and LF6.
It is widely used for welded structures in launch vehicles and spacecraft, such as propellant tanks, ground test fixtures and support frames, and in aircraft for welded fittings, brackets and corrosion-exposed hardware. Bar is machined into flanges, bosses, connectors and fittings that are welded into 5A06 sheet structures, so the whole assembly has consistent strength and corrosion behaviour.
The trade-off is sensitivity to heat: like all high-magnesium alloys, 5A06 should not be held for long periods above about 65 °C, and it is harder to machine cleanly than 6xxx alloys.
5A06 chemical composition (wt %)
| Element | Minimum | Maximum | Role in the alloy |
|---|---|---|---|
| Silicon (Si) | — | 0.40 | Impurity |
| Iron (Fe) | — | 0.40 | Impurity |
| Copper (Cu) | — | 0.10 | Kept low for corrosion resistance |
| Manganese (Mn) | 0.50 | 0.8 | Adds strength, refines grain |
| Magnesium (Mg) | 5.8 | 6.8 | Main strengthening element |
| Zinc (Zn) | — | 0.20 | Impurity |
| Titanium (Ti) | 0.02 | 0.10 | Grain refiner |
| Beryllium (Be) | 0.0001 | 0.005 | Reduces oxidation and magnesium loss in melting and welding |
| Others, each / total | — | 0.05 / 0.10 | |
| Aluminium (Al) | Remainder | — |
Limits per GB/T 3190. Note that AMS 4027, AMS 4115, AMS 4123 and AMS 4154 are 6061 specifications and AMS 4153 does not cover 5A06; these documents should not be cited for 5A06 bar.
Mechanical and physical properties
| Condition | Tensile strength | Yield strength | Elongation | Notes |
|---|---|---|---|---|
| O / H112 extruded bar, specified minimum (indicative) | ≥ 315 MPa | ≥ 155 MPa | ≥ 15 % | Typical GB/T 3191 limits for moderate diameters |
| O, typical | About 330 – 345 MPa | About 160 – 175 MPa | About 20 % | Annealed |
| H112, typical | About 330 – 360 MPa | About 165 – 200 MPa | About 15 – 20 % | As extruded |
| Brinell hardness | About 70 – 85 HB | — | — | Depends on temper and size |
Values vary with diameter and production route. The certificate gives the tested properties of each lot; design to the specified minimum of your order standard.
Physical properties
- Density
- About 2.64 g/cm³
- Modulus of elasticity
- About 70 – 71 GPa
- Thermal conductivity
- About 115 – 120 W/m·K
- Coefficient of thermal expansion
- About 24 µm/m·°C (20 – 100 °C)
- Melting range
- About 570 – 635 °C
5A06 bar sizes and weights
Supply range
- Round bar
- About 5 – 300 mm diameter; larger forged rounds by enquiry
- Square, hexagon and flat
- Squares and hexagons about 6 – 150 mm; flats to about 300 mm wide
- Length
- Commonly 1500, 3000 or 6000 mm, or cut to length
- Tempers
- H112 (as extruded), O (annealed), F
- Tolerances
- GB/T 3191 or as agreed; turned bar for tighter limits
Round bar weight per metre is π/4 × d² × 2.64 ÷ 1000 kg, with d in millimetres.
| Diameter (mm) | kg per metre | kg per 3 m bar | Diameter (in) |
|---|---|---|---|
| 10 | 0.207 | 0.62 | 0.39 |
| 16 | 0.531 | 1.59 | 0.63 |
| 20 | 0.829 | 2.49 | 0.79 |
| 25 | 1.296 | 3.89 | 0.98 |
| 30 | 1.866 | 5.60 | 1.18 |
| 40 | 3.318 | 9.95 | 1.57 |
| 50 | 5.184 | 15.55 | 1.97 |
| 60 | 7.464 | 22.39 | 2.36 |
| 80 | 13.270 | 39.81 | 3.15 |
| 100 | 20.735 | 62.20 | 3.94 |
| 120 | 29.858 | 89.57 | 4.72 |
| 150 | 46.653 | 139.96 | 5.91 |
| 200 | 82.938 | 248.81 | 7.87 |
| 250 | 129.591 | 388.77 | 9.84 |
Equivalents and substitutes
| System | Nearest grade | Comment |
|---|---|---|
| China (former) | LF6 | Same alloy |
| Russia / GOST | AMg6 (1560) | Very close composition; widely used in Russian aerospace |
| AA / EN | 5456, 5083 | Lower magnesium and strength; nearest western stock grades |
| AA / EN | 5059 | High-magnesium marine alloy with zinc and zirconium; not a direct equivalent |
Substituting 5456 or 5083 for 5A06 lowers strength by roughly 5 – 15 % and needs design approval.
Machining, welding and service limits
Welding
Argon-arc TIG and MIG with 5A06-type or ER5556-type filler. Clean oxide carefully; the high magnesium makes the alloy prone to porosity if joints are dirty.
Service temperature
Avoid long exposure above about 65 °C to prevent sensitisation and loss of corrosion resistance.
Corrosion protection
Good bare performance in marine air; anodise or paint for long immersion or galvanic contact with carbon fibre or steel.
Typical uses of 5A06 bar
- Welded tank fittings: flanges, bosses and ports for propellant, fuel and pressurant tanks
- Launch-vehicle and spacecraft hardware: machined brackets and frames welded into 5A06 structures
- Aircraft fittings: corrosion-exposed brackets, connectors and supports
- Marine and naval aviation: deck fittings and hardware
- Ground equipment: fixtures and test frames
How to order 5A06 bar
- SpecifyAlloy and temper, shape and size, length or cut pieces, quantity and the governing specification with its revision (GB/T 3191 or your drawing).
- ConfirmWe confirm the specification can be met, the tolerance class, any extra tests and the delivery terms (EXW, FOB, CIF or DAP).
- InspectMaterial is checked for dimensions and surface condition; tests named on the order are carried out or arranged with an independent laboratory.
- DocumentEach lot ships with a mill test certificate to EN 10204 3.1 showing chemistry and mechanical results, traceable to the cast or lot number.
- Pack and shipExport packing in sealed, moisture-protected wooden cases, crates or pallets, shipped by sea or air to your port or door.
References and standards
- GB/T 3190 – Chemical composition of wrought aluminium and aluminium alloys
- GB/T 3191 – Aluminium and aluminium alloy extruded bars
- GOST 4784 – Aluminium and wrought aluminium alloys: grades (AMg6)
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits (Teal Sheets)
- ASM Handbook, Vol. 2 – Properties and Selection: Nonferrous Alloys and Special-Purpose Materials
5A06 aircraft aluminium (aluminum) bar: FAQs
What is 5A06 equivalent to?
It is the current Chinese name for LF6 and is very close to the Russian AMg6. There is no exact AA or EN equivalent; 5456 and 5083 are the nearest stock alternatives with lower strength.
Can 5A06 bar be heat treated?
No. It is a non-heat-treatable alloy. Bar is supplied as extruded (H112) or annealed (O). Listings that offer 5A06 in T4, T5 or T6 are incorrect.
Is 5A06 weldable?
Yes, by TIG and MIG with a matching high-magnesium filler. It is one of the main alloys for welded launch-vehicle tanks.
What is the maximum service temperature?
For continuous service keep below about 65 °C. Longer exposure at higher temperatures can sensitise the alloy and reduce resistance to intergranular and stress corrosion.
Which AMS specification covers 5A06?
None. 5A06 is a Chinese national grade covered by GB/T standards. AMS numbers sometimes quoted for it belong to other alloys, mainly 6061.
Need 5A06 bar?
Send shape, size, temper, length, quantity and standard. We will reply with availability, certification and a delivered price.
