Titanium Grade 9 (Ti-3Al-2.5V) – UNS R56320
Medium-strength near-alpha titanium alloy, for tubing
Alloy with 3% Al and 2.5% V ('half 6-4'), with strength about 50% higher than CP Ti and cold formability and weldability far superior to Gr 5. It is the standard alloy for aircraft hydraulic tubing, annealed or cold worked and stress relieved (CWSR).
Designations and equivalents
| System | Designation |
|---|---|
| UNS | R56320 |
| W.Nr./EN | 3.7194 / 3.7195 (TiAl3V2.5) |
| DIN | TiAl3V2.5 |
| Trade names | Ti 3-2.5, Ti-3Al-2.5V |
| Others | GB TA18; AMS 4943/4944/4945 (tubing) |
Standards by product form
| Form | Standard |
|---|---|
| Bar | ASTM B348 Gr 9 |
| Plate | ASTM B265 Gr 9 |
| Forging | ASTM B381 F-9 |
| Tube | ASTM B338 Gr 9 / B861; AMS 4943/4944/4945 |
| Wire | ASTM B863 Gr 9 |
| Implant | ASTM F2146 (tubing) / F3046 |
Tolerances and HS codes
- Forged bars (round and square): machining allowance from 2 mm (Ø 6–16 mm) to 24 mm (Ø 400–500 mm) on the diameter. E.g. Ø 100–125 mm finished: +7 mm, tolerance +6 / −0 (length up to 3,500 mm).
- Forged discs: allowance of 4 to 9 mm on the diameter and 3 to 11 mm on the height, plus-only tolerance.
- Cutting and machining: band saw −0 / +5 to +15 mm on length; waterjet +10 % of thickness on the diameter (min. 2 mm); machined parts −0 / +2 to +5 mm on the diameter. See the full tables (INF 002 and INF 003, the same for every alloy).
| Form | NCM (Brazil, 8 digits) | HS (international, 6 digits) | HTS (USA, 10 digits)* | CN (European Union, 8 digits)* |
|---|---|---|---|---|
| Forged bar | 8108.90.00 | 8108.90 | 8108.90.6031 | 8108 90 30 |
| Hot-rolled bar | 8108.90.00 | 8108.90 | 8108.90.6031 | 8108 90 30 |
| Plate (> 10 mm, width ≥ 600 mm) | 8108.90.00 | 8108.90 | 8108.90.6045 | 8108 90 50 |
| Seamless pipe | 8108.90.00 | 8108.90 | 8108.90.6060 | 8108 90 60 |
| Welded pipe | 8108.90.00 | 8108.90 | 8108.90.6060 | 8108 90 60 |
| Flange and fitting | 8108.90.00 | 8108.90 | 8108.90.3060 | 8108 90 90 |
Tariff class: titanium (by chemical composition, under the Chapter 72 Notes and Section XV Note 5).
*: US and EU codes for reference. NCM per current legislation (General Rules of Interpretation, Notes to Chapters 72, 74 and 75 and Section XV Note 5). Confirm the final code with your customs broker according to the item size and finish. HS = first 6 digits of the NCM.
Chemical composition (%)
ASTM B348 Gr 9 (% by mass)
| Element | Range (%) |
|---|---|
| Al | 2.5 – 3.5 |
| V | 2.0 – 3.0 |
| Fe | ≤ 0.25 |
| O | ≤ 0.15 |
| C | ≤ 0.08 |
| N | ≤ 0.03 |
| H | ≤ 0.015 |
| Residuals (each / total) | ≤ 0.10 / ≤ 0.40 |
| Ti | balance |
Mechanical properties
annealed (ASTM B348, room temperature)
| Property | Value |
|---|---|
| Yield strength (0.2%) | ≥ 483 MPa |
| Tensile strength | ≥ 620 MPa |
| Elongation (4D) | ≥ 15% |
| Reduction of area | ≥ 25% |
| CWSR tubing (B338/AMS 4945) | tensile ≥ 860 MPa; yield ≥ 725 MPa (typical specification) |
Typical physical properties
| Property | Value |
|---|---|
| Density | 4.48 g/cm³ |
| Melting range | ≈ 1,590 – 1,640 °C (typical) |
| Modulus of elasticity | ≈ 91 – 110 GPa (typical ≈ 100) |
| Thermal conductivity (20 °C) | ≈ 8.1 W/m·K |
| Thermal expansion (20–100 °C) | ≈ 9.1 µm/m·K (typical) |
| Beta transus | ≈ 935 °C (typical) |
Heat treatment, welding and machining
| Item | Usual practice |
|---|---|
| Service temperature | Structural use up to ~315 °C (usual ASME limit). |
| Heat treatment | Supplied annealed (≈ 650 – 790 °C, air) or cold worked + stress relieved (CWSR, ≈ 370 – 595 °C). Small aging response; normally not used in STA. |
| Welding | Good weldability by TIG with AWS A5.16 ERTi-9 filler; same rigorous gas shielding as CP Ti (pool, trailing shield and root purge until < ~430 °C). |
| Machining | Intermediate between CP Ti and Gr 5; same practices: sharp carbide, low speed and abundant coolant. |
Typical applications
- Aircraft hydraulic and fuel tubing
- Bicycle frames
- Golf club shafts and racquets
- Honeycomb and foil
- Corrosion-resistant tubes and vessels
- Tubular implants (ASTM F2146)
Alternatives: Gr 2 when corrosion resistance and formability are enough; Gr 5 for maximum strength; Gr 18 or Gr 28 (Ti-3-2.5 with Pd or Ru) for crevice corrosion in brines and oil and gas.
Titanium Grade 9 (Ti-3Al-2.5V): complete guide
What titanium Grade 9 is
Grade 9 belongs to the family of titanium and its alloys, in the near-alpha group. With half the aluminum and vanadium of Ti-6Al-4V, hence the name "half 6-4", it sits between commercially pure titanium and the high-strength alloy: it gains strength over Grade 2 without losing the ability to be drawn and cold formed and to be welded.
Corrosion and limits of use
Corrosion resistance is similar to CP titanium in seawater, chlorides, oxidizing media and organic acids, with immunity to pitting and chloride stress corrosion cracking, and slightly lower in reducing acids. The alloy does not resist hydrofluoric acid, hot reducing acids, dry chlorine or anhydrous methanol. Under continuous load, use goes up to about 315 °C.
Applications
High-pressure aircraft hydraulic and fuel tubing, engine ducts and formed components, frames, handlebars and components for bicycles and sporting goods, heat exchange tubes and high-pressure piping in chemical processes, and machined parts that need more strength than Grade 2 and more formability than Grade 5. In seawater without high mechanical loading, Grade 2 remains the standard.
Supply forms and Dustre services
Round bars cut to size on a band saw, with rough or finish machining and hardness and tensile testing. All material is supplied with a 3.1 inspection certificate and heat traceability.
Frequently asked questions
What is the chemical composition of Titanium Grade 9 (Ti-3Al-2.5V)?
Per ASTM B348 Gr 9 (% by mass): Al 2.5 – 3.5; V 2.0 – 3.0; Fe ≤ 0.25; O ≤ 0.15; C ≤ 0.08; N ≤ 0.03.
Which standards cover Titanium Grade 9 (Ti-3Al-2.5V)?
Bar: ASTM B348 Gr 9. Plate: ASTM B265 Gr 9. Forging: ASTM B381 F-9. Tube: ASTM B338 Gr 9 / B861; AMS 4943/4944/4945. Wire: ASTM B863 Gr 9. Implant: ASTM F2146 (tubing) / F3046.
Up to what temperature can Titanium Grade 9 (Ti-3Al-2.5V) be used?
Structural use up to ~315 °C (usual ASME limit).
Which materials can replace Titanium Grade 9 (Ti-3Al-2.5V)?
Gr 2 when corrosion resistance and formability are enough; Gr 5 for maximum strength; Gr 18 or Gr 28 (Ti-3-2.5 with Pd or Ru) for crevice corrosion in brines and oil and gas.
