Closed-die forgings
Near-net shapes for impellers, fittings and frames, with grain flow following the part contour.
Aerospace forgings
2B50 Aerospace Aluminium Forgings
2B50 is a refined version of the 2A50 forging alloy, with chromium and titanium added for finer grain and more consistent properties in complex die forgings. It is used for aircraft fittings, engine-casing parts and impellers built to GB and HB standards. Metline supplies 2B50-T6 die and free forgings with full certification to customers worldwide.
- Alloy
- 2B50 (formerly LD6)
- Temper
- T6
- Standards
- HB 5204 · GJB 2351
- Strength
- Rm ≥ 380 MPa (die, L)
What 2B50 is
2B50, formerly LD6, shares the Al-Mg-Si-Cu base of 2A50 but adds 0.01 – 0.20 % chromium and a controlled 0.02 – 0.10 % titanium. Chromium suppresses recrystallisation and coarse surface grain in forgings, while titanium refines the cast grain of the billet. The result is a forging alloy with more uniform properties in complex shapes.
Like 2A50, it has excellent hot plasticity and fills thin ribs and deep cavities well, so it is used for complex closed-die forgings: airframe fittings, joints, frames, engine-casing parts, guide-vane rings and compressor impellers. Where heat resistance above about 150 °C is needed, 2A70 or 2A80 are the usual alternatives.
A note on data: some published sheets show 2B50 with 1.4 – 1.8 % magnesium and around 1 % nickel. That is the 2A70 composition, not 2B50, and should be corrected before ordering.
2B50 chemical composition (wt %)
Limits per GB/T 3190.
| Element | Limit | Comment |
|---|---|---|
| Copper (Cu) | 1.8 – 2.6 | Strengthening |
| Silicon (Si) | 0.7 – 1.2 | Forms Mg2Si |
| Magnesium (Mg) | 0.40 – 0.80 | Strengthening |
| Manganese (Mn) | 0.40 – 0.80 | Grain control |
| Chromium (Cr) | 0.01 – 0.20 | Inhibits recrystallisation and coarse grain |
| Titanium (Ti) | 0.02 – 0.10 | Grain refiner |
| Iron (Fe) | 0.7 max | Impurity |
| Nickel (Ni) | 0.10 max | Impurity (Fe + Ni ≤ 0.7) |
| Zinc (Zn) | 0.30 max | Impurity |
| Others each / total | 0.05 / 0.10 | |
| Aluminium | Remainder |
Mechanical properties of 2B50-T6 forgings
2B50 forgings are specified at the same minimum levels as 2A50 in the common aviation standards, with the benefit of more uniform results across complex parts.
| 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.
Physical data (approximate)
- Density
- about 2.75 g/cm³
- Melting range
- roughly 555 – 640 °C
- Modulus of elasticity
- about 71 GPa
2B50 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 finishing
- Forging: good hot plasticity; chromium helps limit coarse recrystallised grain at the forging surface.
- Heat treatment: solution treatment around 500 – 520 °C, rapid water quench, artificial ageing to T6.
- Machining: good with carbide tooling; mill, drill and turn conventionally.
- Finishing: takes anodising and paint well, which are needed for corrosion protection.
- Joining: mechanical fastening; not intended for fusion welding.
Applications of 2B50 forgings
- Airframe fittings, frames and joints in wing and fuselage structure
- Engine-casing parts, guide-vane rings and bearing housings that run cool to moderately warm
- Compressor impellers and fans of complex shape
- Structural parts for missiles, satellites and launch vehicles built to GB standards
2B50 compared with 2A50, 2A70 and 2014
| Factor | 2B50 | 2A50 | 2A70 | 2A14 / 2014 |
|---|---|---|---|---|
| Forgeability | Excellent | Excellent | Good | Good |
| Grain uniformity | Better (Cr, Ti) | Good | Good | Good |
| Heat resistance | Fair | Fair | Very good | Fair |
| Room-temperature strength | Medium–high | Medium–high | Medium–high | High |
Choose 2B50 over 2A50 when a complex forging needs consistent properties throughout; choose 2A70 when the part runs hot; choose 2A14 when maximum room-temperature strength matters.
How to order 2B50 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)
2B50 aluminium (aluminum) forgings: FAQ
What is the difference between 2B50 and 2A50?
2B50 adds chromium (0.01 – 0.20 %) and controlled titanium (0.02 – 0.10 %) to the 2A50 base, giving finer, more uniform grain and more consistent properties in complex forgings.
Does 2B50 contain nickel?
Only as an impurity (0.10 % max). Data sheets that show around 1 % nickel and 1.4 – 1.8 % magnesium are describing 2A70, not 2B50.
What strength do 2B50-T6 forgings achieve?
Die forgings are commonly specified at about 380 MPa minimum tensile and 275 MPa yield strength longitudinally, with lower transverse values.
Is 2B50 corrosion resistant?
Moderately. As a copper-bearing alloy it should be anodised, conversion coated or painted for aerospace service.
Do you supply 2B50 forgings outside China and India?
Yes. Metline supplies forgings worldwide with EN 10204 3.1 certificates, inspection reports and export packing.
Need 2B50 forgings for complex parts?
Send the drawing, standard and quantity. We will confirm feasibility, inspection and a delivered price.
