TI · titanium
Titanium Ti-6Al-4V ELI (Grade 23)
The same alloy as Grade 5 with tighter limits on oxygen, nitrogen and iron. Slightly softer and tougher, and it machines about the same - the premium is in the certification and the stock, not the cut.
Quoting this material
- Typical lead time
- 15–25 working days
- Condition
- Annealed (ELI chemistry)
- Achievable finish
- Ra 1.6 µm typical · Ra 0.4 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.
The same alloy as Grade 5 with tighter limits on oxygen, nitrogen and iron. Slightly softer and tougher, and it machines about the same - the premium is in the certification and the stock, not the cut.
Properties as supplied
| Parameter | Value | Unit |
|---|---|---|
| Tensile strength | 860–965 | MPa |
| Yield strength (0.2%) | 795–875 | MPa |
| Elongation | 10–15 | % |
| Hardness | ~32 | HRC |
| Thermal conductivity | 6.6 | W/m·K |
| Modulus of elasticity | 113.8 | 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 (ELI chemistry)
Heat treatment
Annealed as supplied. The ELI designation is about chemistry - lower interstitials give higher fracture toughness and better ductility at cryogenic temperature, neither of which is created by a heat treatment.
Achievable surface finish
Ra 1.6 µm
Ra 0.4 µm
Medical devices frequently require a specific surface finish plus an electropolished or passivated finish; the finish is part of the device specification, not a shop default.
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 geometry
Coolant
- High-pressure flood; no chlorinated fluids, and cleanliness is auditable on medical work
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
- Orthopaedic implants and bone screws
- Dental implant components
- Surgical instrument bodies
- Cryogenic and LNG components
- Aerospace fracture-critical fittings
DFM notes for this grade
- Tighter chemistry limits mean tighter material certification - do not substitute Grade 5 for a Grade 23 callout, however close the mechanical properties look
- Higher fracture toughness means the material is less likely to crack in service, but it also means it can be trickier to break a chip cleanly
- Where the part is an implant, the surface finish and the cleanliness of the process are part of the acceptance criteria, not secondary
Questions buyers ask
- What does ELI actually change?
- The interstitial content - lower oxygen, nitrogen and iron. That increases fracture toughness and ductility, which matters for an implant that will see cyclic load for twenty years, and it keeps the material from becoming brittle at cryogenic temperature. The mechanical properties on the datasheet look similar; the behaviour under a crack does not.
- Can you machine Grade 5 for a part specified in Grade 23?
- No. The specification is on the material certificate, and a Grade 5 certificate cannot be presented as Grade 23. It is the one substitution in this catalogue that is never a judgement call.
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.
17-4 PH
4/10In the annealed condition it machines like a tough 304; in H900 it is hard enough that finishing has to be done by grinding or hard turning.