Titanium Grade 9 is a medium-strength titanium alloy containing about 3% aluminium and 2.5% vanadium (Ti-3Al-2.5V). This datasheet presents the material within the American (ASTM / ASME / UNS) standard system.
Often called the "half-alloy", Titanium Grade 9 is intermediate in strength between the commercially pure grades and Ti-6Al-4V (Grade 5), with strength 30–50% higher than unalloyed titanium. It was developed specifically for tubing and foil because it combines this raised strength with excellent cold formability — the cold-forming characteristics that Ti-6Al-4V lacks — and it can be further strengthened by cold work. The aluminium stabilises and strengthens the alpha phase while the vanadium stabilises the beta phase, improving formability, toughness and weldability. It offers an excellent strength-to-weight ratio and the good corrosion resistance characteristic of titanium, and is readily welded by inert-gas processes.
Typical applications include aircraft hydraulic and fuel tubing, foil, honeycomb, sporting goods (bicycle frames, golf shafts), and pressure-tubing for aerospace and industrial use.
| Property | Value | Unit |
|---|---|---|
| Density | 4.48 | g/cm³ |
| Melting range | 1600–1650 | °C |
| Elastic modulus | 100 | GPa |
| Coefficient of thermal expansion (20–100 °C) | 9.5 | µm/m·°C |
| Thermal conductivity (20 °C) | 7.6 | W/m·K |
| Specific heat (20 °C) | 544 | J/kg·K |
| Structure | Near-alpha (alpha-beta) | — |
| Element | Symbol | Min % | Max % | Role in Alloy |
|---|---|---|---|---|
| Titanium | Ti | Balance | — | Base element |
| Aluminium | Al | 2.50 | 3.50 | Alpha stabiliser; strength |
| Vanadium | V | 2.00 | 3.00 | Beta stabiliser; formability, toughness |
| Iron | Fe | — | 0.25 | Residual |
| Oxygen | O | — | 0.15 | Interstitial; strength |
| Carbon | C | — | 0.08 | Interstitial impurity |
| Nitrogen | N | — | 0.03 | Interstitial impurity |
| Hydrogen | H | — | 0.015 | Interstitial impurity |
Annealed condition, per ASTM B265 for UNS R56320.
| Condition | Property | Value |
|---|---|---|
| Annealed | Tensile strength (UTS) | ≥620 MPa (90 ksi) |
| Annealed | 0.2% yield strength | ≥483 MPa (70 ksi) |
| Annealed | Elongation at break | ≥15 % |
| Cold-worked stress-relieved | Tensile strength (UTS) | up to ~860 MPa (125 ksi) |
| — | Elastic modulus | 100 GPa |
Confirm against the mill test report. Strengthened by cold work; cold-worked stress-relieved tubing has higher strength than the annealed values.
| Environment | Performance | Notes |
|---|---|---|
| Atmospheric / general | Excellent | Titanium oxide film |
| Seawater / marine | Excellent | Resists chloride attack |
| Oxidizing acids | Excellent | Stable passive film |
| Chloride stress-corrosion cracking | Very Good | Generally resistant |
| Elevated temperature | Good | Useful to moderate temperatures |
Corrosion resistance is characteristic of titanium — excellent in seawater, chlorides and oxidizing media — combined with a high strength-to-weight ratio.
A medium-strength titanium alloy; primarily strengthened by cold work rather than heat treatment. Properties are set by annealing and cold work.
Anneal Anneal at approximately 650–760 °C and air cool. Cold-worked, stress-relieved tubing is given a lower-temperature stress relief (~370–480 °C). Protect from oxygen, nitrogen and hydrogen pickup at temperature.
Readily welded by inert-gas processes; the weld pool and cooling weld must be fully shielded from atmospheric contamination, which causes embrittlement. Matching filler is used.
| Welding Process | Applicability | Filler / Consumable |
|---|---|---|
| GTAW / TIG | Excellent | AWS A5.16 ERTi-9 (matching) |
| GMAW / MIG | Good | ERTi-9 |
| Automatic tube welding | Excellent | With built-in gas-purge chambers |
Use full inert-gas shielding and clean, contamination-free surfaces; avoid hydrogen, oxygen and nitrogen pickup.
Machining Guidelines
| Parameter | Recommendation |
|---|---|
| Machinability | Moderate; settings similar to stainless steel |
| Work hardening | Strengthens by cold work |
| Coolant | Generous non-chlorinated coolant |
Forming Processes
| Process | Notes |
|---|---|
| Cold forming | Excellent — developed for tube and foil forming |
| Hot forming | Performed hot; anneal afterward; protect from contamination |
| Industry | Typical Components | Key Requirements |
|---|---|---|
| Aerospace | Hydraulic and fuel tubing, foil, honeycomb | Strength-to-weight + cold formability |
| Sporting goods | Bicycle frames, golf shafts | Strength-to-weight + formability |
| Industrial | Pressure tubing, structural tube | Strength + corrosion resistance |
| Marine | Tubing and components | Corrosion resistance |
| Product Form | ASTM Standard | AMS |
|---|---|---|
| Seamless tubing | ASTM B338 | AMS 4943 / 4944 / 4945 |
| Sheet, strip and plate | ASTM B265 | — |
| Wire, bar and billet | ASTM B348 (Grade 9) | — |
| Welding wire | AWS A5.16 ERTi-9 | — |
Ti-3Al-2.5V medium-strength titanium alloy. UNS R56320.
| Grade | Al % | V % | Type | Best Used For |
|---|---|---|---|---|
| Titanium Grade 9 | 2.5–3.5 | 2–3 | Near-alpha | Ti-3Al-2.5V; tubing, cold formable, medium strength |
| Titanium Grade 5 | 5.5–6.75 | 3.5–4.5 | Alpha-beta | Ti-6Al-4V; most-used high-strength alloy |
| Titanium Grade 2 | — | — | CP (unalloyed) | Workhorse commercially pure titanium |
| Titanium Grade 18 | 2.5–3.5 | 2–3 | Near-alpha | Grade 9 + Pd; enhanced corrosion |
| Titanium Grade 28 | 2.5–3.5 | 2–3 | Near-alpha | Grade 9 + Ru; enhanced corrosion |




