TI · titanium
Titanium Grade 7 (commercially pure, palladium-stabilised)
Grade 2 chemistry with a small palladium addition. Machines like Grade 2 and resists reducing acids that plain titanium cannot handle.
Quoting this material
- Typical lead time
- 15–25 working days
- Condition
- Annealed
- 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.
Grade 2 chemistry with a small palladium addition. Machines like Grade 2 and resists reducing acids that plain titanium cannot handle.
Properties as supplied
| Parameter | Value | Unit |
|---|---|---|
| Tensile strength | 345 | MPa |
| Yield strength (0.2%) | 275 | MPa |
| Elongation | 20 | % |
| Hardness | ~160 | HV |
| Palladium content | 0.12–0.25 | % |
| Modulus of elasticity | 102 | 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; annealing is a stress relief only.
Achievable surface finish
Ra 1.6 µm
Ra 0.4 µm
Same chloride-free cutting-fluid rule as every titanium grade; cleanliness matters where the part is for chemical service.
Tooling and cutting parameters
Cutting speed
- 50–100 m/min (carbide)
Feed
- 0.10–0.25 mm/rev turning · 0.06–0.14 mm/tooth milling
Tooling
- Uncoated fine-grain carbide, sharp positive geometry
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
- Chemical process equipment
- Reducer and acid service components
- Heat exchanger tubes and tubesheets
- Pulp and paper bleaching equipment
- Desalination and brine handling
DFM notes for this grade
- The palladium is there for a chemical reason, not a mechanical one - do not substitute Grade 2 to save cost on a reducer-acid service
- Mechanically it behaves like Grade 2, so the stiffness and strength limits are the same
- Any iron contamination from tooling or handling becomes a corrosion site in chemical service; cleanliness of the process is auditable
Questions buyers ask
- Why does Grade 7 exist when Grade 2 already resists corrosion?
- Because titanium has a blind spot: reducing acids and some chloride environments attack it, and the passive film does not reform. The palladium addition promotes passivation in those conditions, which is why Grade 7 goes into acid service where Grade 2 fails.
- How much does the palladium cost?
- It is a small percentage of a material that is already expensive, and the premium is real but rarely the deciding factor - the alternative in a reducer-acid service is usually a nickel alloy with worse mechanical properties and its own cost.
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.
Hastelloy C-276
1/10One of the hardest materials in this catalogue: very tough, work-hardening, and abrasive.