Titanium Grade 7 is a palladium-bearing commercially pure titanium (Ti-0.15Pd) developed for enhanced corrosion resistance. This datasheet presents the material within the American (ASTM / ASME / UNS) standard system.
With a minimum titanium content of about 99.0% and slightly higher interstitial (oxygen and iron) content than Grade 1, Grade 2 offers the best overall balance of strength, ductility, formability, weldability and corrosion resistance of the commercially pure grades, which has made it the most widely used. It is moderately stronger than Grade 1 while retaining good formability. It combines this with the excellent corrosion resistance characteristic of titanium — a stable, self-healing oxide film gives high resistance to seawater, chlorides, nitric acid and many oxidizing media — together with good weldability and excellent biocompatibility.
Typical applications include plate heat exchangers and condenser tubing, deep-drawn and severely formed components, chemical and marine equipment, cryogenic vessels, cathodic-protection anodes, and medical implants and surgical instruments.
| Property | Value | Unit |
|---|---|---|
| Density | 4.51 | g/cm³ |
| Melting point | 1670 | °C |
| Elastic modulus | 103 | GPa |
| Coefficient of thermal expansion (20–100 °C) | 8.6 | µm/m·°C |
| Thermal conductivity (20 °C) | 16 | W/m·K |
| Specific heat (20 °C) | 523 | J/kg·K |
| Structure | Alpha (hexagonal close-packed) | — |
| Element | Symbol | Min % | Max % | Role in Alloy |
|---|---|---|---|---|
| Titanium | Ti | Balance | — | Base element |
| Palladium | Pd | 0.12 | 0.25 | Enhances corrosion resistance |
| Iron | Fe | — | 0.30 | Residual |
| Oxygen | O | — | 0.25 | Interstitial; strength |
| Carbon | C | — | 0.08 | Interstitial impurity |
| Nitrogen | N | — | 0.03 | Interstitial impurity |
| Hydrogen | H | — | 0.015 | Interstitial impurity |
Annealed condition, per ASTM B265 for UNS R52400 (mechanically equivalent to Grade 2).
| Condition | Property | Value |
|---|---|---|
| Annealed | Tensile strength (UTS) | ≥345 MPa (50 ksi) |
| Annealed | 0.2% yield strength | 275–450 MPa (40–65 ksi) |
| Annealed | Elongation at break | ≥20 % |
| Annealed | Hardness | ~160 HB |
| — | Elastic modulus | 103 GPa |
Confirm against the mill test report. Properties cannot be increased by heat treatment; cold work raises strength.
| Environment | Performance | Notes |
|---|---|---|
| Reducing acids (HCl, H₂SO₄) | Excellent | Palladium greatly improves resistance vs unalloyed Ti |
| Crevice corrosion (hot chlorides) | Excellent | Major advantage of the Pd addition |
| Seawater / marine | Excellent | Self-healing oxide film |
| Oxidizing acids (e.g. nitric) | Excellent | Stable passive film |
| Chloride stress-corrosion cracking | Excellent | Highly resistant |
The palladium addition gives Grade 7 the best corrosion resistance of the titanium grades — particularly in hot reducing acids and chloride-bearing media where it strongly resists crevice corrosion — making it the standard choice for severe corrosive service.
A commercially pure (alpha) titanium; not hardenable by heat treatment. Properties are set by annealing and cold work.
Anneal Anneal at approximately 650–760 °C and air cool to relieve stress and restore ductility after cold work. Protect from oxygen, nitrogen and hydrogen pickup at temperature; avoid hydrogen-bearing atmospheres.
Excellent weldability with inert-gas processes; the weld must be fully shielded (including the root and cooling weld) from atmospheric contamination, which causes embrittlement.
| Welding Process | Applicability | Filler / Consumable |
|---|---|---|
| GTAW / TIG | Excellent | AWS A5.16 ERTi-7 (matching) |
| GMAW / MIG | Good | ERTi-7 |
| Resistance / spot | Good | — |
Use full inert-gas shielding and clean, contamination-free surfaces; avoid hydrogen, oxygen and nitrogen pickup.
Machining Guidelines
| Parameter | Recommendation |
|---|---|
| Machinability | Moderate; sharp tools, low speed, high feed |
| Work hardening | Low for CP titanium; avoid galling |
| Coolant | Generous non-chlorinated coolant |
Forming Processes
| Process | Notes |
|---|---|
| Cold forming | Excellent — deep drawing, severe bending, stamping |
| Hot forming | ~600–800 °C; protect from contamination; anneal afterward |
| Industry | Typical Components | Key Requirements |
|---|---|---|
| Chemical processing | Reactors, heat exchangers, columns in reducing acids | Crevice / reducing-acid resistance |
| Chlor-alkali | Cells and components in hot chlorides | Crevice corrosion resistance |
| Hydrometallurgy | Autoclaves, leaching equipment | Severe corrosive resistance |
| Marine / desalination | Harsh-environment parts | Corrosion resistance |
| Product Form | ASTM Standard | ASME Code |
|---|---|---|
| Sheet, strip and plate | ASTM B265 | ASME SB-265 |
| Bar and billet | ASTM B348 | ASME SB-348 |
| Seamless / welded tube | ASTM B338 | ASME SB-338 |
| Welding wire | AWS A5.16 ERTi-7 | — |
Palladium-bearing commercially pure titanium (Ti-0.15Pd). UNS R52400.
| Grade | Ti % | O max % | Fe max % | Best Used For |
|---|---|---|---|---|
| Titanium Grade 7 | bal | Pd 0.12–0.25 | 0.30 | Ti-0.15Pd; best corrosion resistance (reducing acids, crevice) |
| Titanium Grade 2 | ≥99.0 | — | 0.30 | Workhorse CP titanium (Grade 7 base) |
| Titanium Grade 3 | ≥99.0 | 0.35 | 0.30 | Higher-strength CP titanium |
| Titanium Grade 4 | ≥98.9 | 0.40 | 0.50 | Strongest CP titanium; moderate formability |
| Titanium Grade 7 | ≥98.9 | 0.25 | 0.30 | CP titanium + Pd; enhanced acid resistance |




