TI · titanium
Titanium Ti-15V-3Cr-3Sn-3Al (Ti-15-3)
A metastable beta alloy: soft and stringy in the annealed state, and ageing takes it to high strength. Its reputation comes from being formable as sheet and then aged to strength in the finished part.
Quoting this material
- Typical lead time
- 18–28 working days
- Condition
- Solution treated (ST) for forming and machining, then aged
- 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 metastable beta alloy: soft and stringy in the annealed state, and ageing takes it to high strength. Its reputation comes from being formable as sheet and then aged to strength in the finished part.
Properties as supplied
| Parameter | Value | Unit |
|---|---|---|
| Tensile strength (aged) | 1,000–1,200 | MPa |
| Yield strength (aged) | 950–1,150 | MPa |
| Elongation (aged) | 8 | % |
| Hardness (aged) | ~42 | HRC |
| Thermal conductivity | ~7 | W/m·K |
| Modulus of elasticity | 103 | 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
Solution treated (ST) for forming and machining, then aged
Heat treatment
Age at roughly 480–540 °C to precipitation harden after machining, which allows a complex part to be formed and machined in a soft, ductile state and then brought to strength. Ageing distorts the part, so critical dimensions are finished afterwards.
Achievable surface finish
Ra 1.6 µm
Ra 0.8 µm
Older aerospace parts are often shot peened after ageing for fatigue performance.
Tooling and cutting parameters
Cutting speed
- 40–80 m/min (carbide)
Feed
- 0.08–0.20 mm/rev turning · 0.05–0.12 mm/tooth milling
Tooling
- Uncoated fine-grain carbide, sharp geometry; the aged condition is harder on the tool
Coolant
- High-pressure flood; no chlorinated fluids
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 sheet and formed structure
- Springs and clips
- Fasteners in high-strength service
- Skin panels and doublers
- High-strength brackets
DFM notes for this grade
- Ageing after machining moves the part - the finish-machining sequence has to follow the age, not precede it
- It machines stringy and gummy in the solution-treated condition, so chip control on a deep bore is a genuine planning item
- The payoff is a part that is formed and machined soft and then aged to 1,200 MPa, which is why it is used where a formed high-strength part is needed
Questions buyers ask
- What is a beta titanium alloy for?
- Formability plus strength that arrives later. Beta alloys can be worked and machined in a soft state, formed into complex shapes, then aged to high strength. That is not possible with an alpha-beta alloy like 6Al-4V, which is hard from the start.
- Does ageing after machining distort the part?
- Yes, and predictably. The age pulls the part slightly, so any tolerance below about 0.1 mm has to be finished after the age. Plan the sequence so the critical surfaces are the last operation.