Closed-die forgings
Near-net shapes for impellers, fittings and frames, with grain flow following the part contour.
Aerospace forgings
2A50 Aerospace Aluminium Forgings
2A50 is an aluminium-magnesium-silicon-copper forging alloy from the GB system, prized for how easily it fills complex dies while reaching good strength in the T6 condition. It is used for aircraft fittings, frames, brackets and compressor impellers. Metline supplies 2A50 die and free forgings to HB 5204 and GJB 2351 for customers worldwide.
- Alloy
- 2A50 (formerly LD5)
- Temper
- T6
- Standards
- HB 5204 · GJB 2351
- Strength
- Rm ≥ 380 MPa (die, L)
What 2A50 is and why it is forged
2A50, previously LD5, is one of the "forging aluminium" (LD) alloys of the Chinese system. Its strength comes from both Mg2Si, as in 6061, and copper-bearing precipitates, as in 2014. The combination gives better forgeability than 2014 with higher strength than 6061.
The alloy flows well at forging temperature, around 380 – 480 °C, so it can fill thin ribs and deep cavities in closed dies without laps or cracks. That makes it the natural choice for parts of complex shape and medium strength: fittings, joints, frames, rocker arms, compressor impellers and fan parts.
Its weaknesses are typical of copper-bearing alloys: moderate corrosion resistance that calls for anodising or painting, some tendency to intergranular corrosion if overheated or slowly quenched, and poor fusion weldability. The higher-strength, chromium-containing variant 2B50 is used where slightly better properties are required.
2A50 chemical composition (wt %)
Limits per GB/T 3190.
| Element | Limit | Comment |
|---|---|---|
| Copper (Cu) | 1.8 – 2.6 | Strengthening; makes it a 2xxx alloy |
| Silicon (Si) | 0.7 – 1.2 | Forms Mg2Si with magnesium |
| Magnesium (Mg) | 0.40 – 0.80 | Strengthening with Si and Cu |
| Manganese (Mn) | 0.40 – 0.80 | Grain control and strength |
| Iron (Fe) | 0.7 max | Impurity |
| Nickel (Ni) | 0.10 max | Impurity (Fe + Ni ≤ 0.7) |
| Zinc (Zn) | 0.30 max | Impurity |
| Titanium (Ti) | 0.15 max | Grain refiner |
| Others each / total | 0.05 / 0.10 | |
| Aluminium | Remainder |
Mechanical properties of 2A50-T6 forgings
Forging properties depend on test direction. Longitudinal values, along the grain flow, are highest; short-transverse values, across the thickness, are lowest and often govern thick fittings.
| Direction | Property | Free forgings (T6) | Die forgings (T6) |
|---|---|---|---|
| Longitudinal (L) | Tensile strength Rm | ≥ 365 MPa | ≥ 380 MPa |
| Longitudinal (L) | Yield strength Rp0.2 | — | ≥ 275 MPa |
| Longitudinal (L) | Elongation A5 | ≥ 8 – 9 % | ≥ 10 – 11 % |
| Long transverse (LT) | Tensile strength Rm | ≥ 345 MPa | ≥ 365 MPa |
| Long transverse (LT) | Elongation A5 | ≥ 6 % | ≥ 7 % |
| Short transverse (ST) | Tensile strength Rm | ≥ 335 MPa | ≥ 345 MPa |
| Short transverse (ST) | Elongation A5 | ≥ 4 % | ≥ 5 % |
| — | Hardness | ≈ 95 HBS | ≈ 100 HBS |
Minimum values as commonly quoted from GJB 2351 and HB 5204 for forgings of typical section; limits depend on section thickness and the standard revision. The ordered standard and certificate govern.
Claims that 2A50 reaches 550 – 610 MPa tensile strength are not correct; those figures belong to 7xxx alloys. Typical T6 forgings achieve about 380 – 420 MPa longitudinally.
Physical data (approximate)
- Density
- about 2.75 g/cm³
- Melting range
- roughly 555 – 640 °C
- Modulus of elasticity
- about 71 GPa
2A50 forging types
Open-die (free) forgings
Blocks, discs and stepped shapes for machining, used for prototypes and low volumes.
Rings and discs
Upset and ring-rolled blanks for rotating and casing parts.
Forged bar
Round and square forged bar for heavy machined components.
Forgings are produced through qualified forging partners to your drawing. Achievable size and weight depend on the forging route and heat-treatment equipment, so feasibility is confirmed for each drawing rather than quoted from a generic table.
Forging, heat treatment and machining
- Forging: good plasticity in the hot range; die temperature and strain rate are controlled to avoid coarse grain at the surface.
- Heat treatment: solution treatment around 500 – 520 °C, water quench, then artificial ageing to T6; follow the governing standard.
- Quench sensitivity: delays between furnace and quench reduce strength and corrosion resistance, so transfer must be fast.
- Machining: good in T6 with conventional carbide tools.
- Surface protection: sulphuric or chromic anodising, or conversion coating and primer.
- Joining: mechanical fastening; fusion welding is not recommended for load-bearing joints.
Applications of 2A50 forgings
- Airframe fittings, joints, brackets and frame segments of complex shape
- Compressor impellers and fan parts that need good forgeability
- Rocker arms, levers and control-system parts
- General aerospace and defence hardware forged to GB/HB standards
2A50 compared with 2B50, 2A14 and 6061
| Factor | 2A50 | 2B50 | 2A14 (≈ 2014) | 6061 |
|---|---|---|---|---|
| Forgeability | Excellent | Excellent | Good | Excellent |
| T6 strength | Medium–high | Medium–high, slightly higher | High | Medium |
| Corrosion resistance | Moderate | Moderate | Lower | Good |
| Typical use | Complex fittings | Complex, higher-stress fittings | Heavy-duty fittings | General forgings |
The nearest Western comparison for 2A50 is 2014 (2A14) in strength and 6061 in forgeability; it is often compared with the Russian AK6 forging alloy.
How to order 2A50 forgings
- Drawing and standardForging or part drawing, alloy, temper (T6), and governing standard such as HB 5204, GJB 2351 or GB/T 3190 chemistry.
- InspectionUltrasonic class (e.g. GB/T 6519 or AMS-STD-2154), grain-flow or macro-etch checks, test-coupon location.
- QuotationWe confirm feasibility, tooling where needed, certification and delivery terms (EXW, FOB, CIF or DAP).
- DocumentsEN 10204 3.1 certificate with chemistry, mechanical results and heat-treat lot traceability.
- PackingCorrosion-protected forgings in wooden cases for export.
References and standards
- GB/T 3190 – Chemical composition of wrought aluminium and aluminium alloys
- HB 5204 – Aluminium alloy forgings for aviation (Chinese aviation industry standard)
- GJB 2351 – Specification for aluminium alloy forgings for aerospace (Chinese military standard)
- ASTM B247 – Aluminum and Aluminum-Alloy Die Forgings, Hand Forgings, and Rolled Ring Forgings (for Western comparison)
2A50 aluminium (aluminum) forgings: FAQ
What is 2A50 aluminium?
A Chinese GB forging alloy (formerly LD5) based on Al-Mg-Si-Cu. It forges very well into complex shapes and reaches medium-high strength in T6.
What is the strength of 2A50-T6 forgings?
Die forgings are typically specified at about 380 MPa minimum tensile strength and 275 MPa yield longitudinally, with lower values in the transverse directions.
What is the difference between 2A50 and 2B50?
2B50 adds small amounts of chromium and titanium for better grain control and slightly higher strength, and is used for more highly stressed complex forgings.
Is there an equivalent to 2A50?
There is no exact ASTM equivalent. It sits between 6061 and 2014 in strength and is often compared with the Russian AK6 alloy.
Can 2A50 forgings be welded?
Fusion welding is not recommended for structural joints; parts are joined mechanically.
Need 2A50 forgings to a GB or HB standard?
Send the drawing and requirements. We will confirm feasibility, inspection and a delivered price.
