TI · titanium
Titanium Ti-5Al-2.5Sn (Grade 6)
An alpha alloy: similar machining behaviour to Ti-6Al-4V with slightly better weldability and lower strength. Used where the joint matters as much as the load.
Quoting this material
- Typical lead time
- 15–25 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.
An alpha alloy: similar machining behaviour to Ti-6Al-4V with slightly better weldability and lower strength. Used where the joint matters as much as the load.
Properties as supplied
| Parameter | Value | Unit |
|---|---|---|
| Tensile strength | 790 | MPa |
| Yield strength (0.2%) | 730 | MPa |
| Elongation | 16 | % |
| Hardness | ~320 | HB |
| Thermal conductivity | ~7 | W/m·K |
| Modulus of elasticity | 110 | 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 appreciably hardenable by heat treatment; it is an alpha-phase alloy. Annealing is a stress-relief operation after welding.
Achievable surface finish
Ra 1.6 µm
Ra 0.8 µm
Finishes like other titanium alpha alloys; contamination control is the same.
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 positive rake
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 welded fabrications
- Cryogenic tankage and pipework
- Aerospace ducting and brackets
- High-temperature airframe parts
- Pressure vessels for aerospace
DFM notes for this grade
- Chosen for weldability more than strength: it joins more readily than Ti-6Al-4V and still carries a useful load
- Welded assemblies need the inert-atmosphere discipline on both faces; a contaminated weld here cannot be reworked
- Slightly lower strength than 6Al-4V means the section may have to grow - check the stiffness, not just the stress
Questions buyers ask
- Why specify Ti-5Al-2.5Sn rather than Ti-6Al-4V?
- Weldability and cryogenic behaviour. The alpha alloy welds more predictably and holds its properties at low temperature, which is why it shows up on tankage and ducting where the assembly is welded and the part is not the primary load path.
- Is it easier to machine than Ti-6Al-4V?
- Marginally, and mostly because it is a little softer. The rules are identical - low speed, sharp tool, high-pressure coolant, no dwelling. Do not expect a materially different cycle time.
Grades we would quote instead
Ti-6Al-4V
3/10The alloy the whole titanium reputation comes from.
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.
Grade 2
5/10The easiest titanium to cut and still awkward by steel standards.