TI · titanium
Titanium Ti-3Al-2.5V (Grade 9)
A leaner alloy than 6Al-4V, developed for tubing: easier to form and weld, and easier to machine while still beating commercially pure grades on strength.
Quoting this material
- Typical lead time
- 12–20 working days
- Condition
- Annealed
- Achievable finish
- Ra 1.6 µm typical · Ra 0.8 µm best
Machined in-house to your drawing: see the precision CNC machining service and the machine and inspection capability it runs on.
Machinability
Our own 1–10 shop ranking, not a published index: 10 is free-cutting brass C360, 1 is Inconel 718. It ranks how a material behaves on the floor - cycle time, chip control and tool life together. Where a published index exists it is quoted in the note.
A leaner alloy than 6Al-4V, developed for tubing: easier to form and weld, and easier to machine while still beating commercially pure grades on strength.
Properties as supplied
| Parameter | Value | Unit |
|---|---|---|
| Tensile strength | 620 | MPa |
| Yield strength (0.2%) | 520 | MPa |
| Elongation | 15 | % |
| Hardness | ~250 | HB |
| Thermal conductivity | ~8 | W/m·K |
| Modulus of elasticity | 100 | GPa |
Hardness, tensile and thermal figures are typical published values for the condition stated. Actual mill certificates govern; send the specification with the drawing and we confirm against the certificate before the material is cut.
Condition
Annealed
Heat treatment
Not hardenable by heat treatment to any useful degree; it is a lean alpha-beta alloy.
Achievable surface finish
Ra 1.6 µm
Ra 0.8 µm
Tubing is usually supplied to a controlled finish; machined ends and fittings follow the same rules as other titanium.
Tooling and cutting parameters
Cutting speed
- 50–100 m/min (carbide)
Feed
- 0.08–0.20 mm/rev turning · 0.05–0.14 mm/tooth milling
Tooling
- Uncoated fine-grain carbide, sharp positive rake
Coolant
- High-pressure flood
Starting points for carbide on a rigid setup, not a guarantee. The right numbers depend on the machine, the toolholder and the fixturing - ask and we will say what we would actually run.
Typical applications
- Aerospace hydraulic tubing
- Fuel and pneumatic lines
- Bicycle frames and components
- Medical tubing assemblies
- Marine hydraulic systems
DFM notes for this grade
- It exists for tube: if the design is a machined solid part rather than a formed tube, Ti-6Al-4V or Grade 4 is usually the better-specified material
- Thin-wall tubing deflects badly under a chuck - machine the ends with a collet and light pressure, or the wall will go oval
- Machined tube ends need a stress-relieved cut: a sharp groove on a pressurised tube is a fatigue site
Questions buyers ask
- Why is Ti-3Al-2.5V used for tubing rather than Ti-6Al-4V?
- Formability and weldability at tube wall thicknesses. It bends further without cracking and welds more forgivingly, while still giving roughly 80% more strength than Grade 2 - the right combination for a pressurised line.
- How do you hold a thin-wall titanium tube for machining?
- With support, not force: a collet or an expanding mandrel that gives even contact, light clamping pressure and a backing material inside if the cut is near the end. A three-jaw chuck on a thin titanium tube will oval it and the cut will then rub.
Grades we would quote instead
Grade 2
5/10The easiest titanium to cut and still awkward by steel standards.
Grade 4
4/10The strongest of the commercially pure grades - roughly the strength of a mild steel with the corrosion resistance of titanium, and about as hard to cut as a stainless.
Ti-6Al-4V
3/10The alloy the whole titanium reputation comes from.