Titanium Grade 4 is the highest-strength member of the commercially pure (unalloyed) titanium grades. This datasheet presents the material within the American (ASTM / ASME / UNS) standard system.
With the highest interstitial (oxygen and iron) content of the commercially pure grades, Titanium Grade 4 offers the highest strength of the unalloyed titanium grades while retaining good formability and weldability. The higher oxygen raises strength at the expense of some ductility relative to the lower grades. It combines this strength 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, and is suited to strength up to about 200 °C with oxidation resistance to about 315 °C.
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 (≥99.0%) |
| Oxygen | O | — | 0.40 | Interstitial; strength vs ductility |
| Iron | Fe | — | 0.50 | Residual; highest of CP grades |
| Carbon | C | — | 0.08 | Interstitial impurity |
| Nitrogen | N | — | 0.05 | Interstitial impurity |
| Hydrogen | H | — | 0.015 | Interstitial impurity |
Annealed condition, per ASTM B265 for UNS R50700.
| Condition | Property | Value |
|---|---|---|
| Annealed | Tensile strength (UTS) | ≥550 MPa (80 ksi) |
| Annealed | 0.2% yield strength | 483–655 MPa (70–95 ksi) |
| Annealed | Elongation at break | ≥15 % |
| Annealed | Hardness | ~265 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 |
|---|---|---|
| Seawater / marine | Excellent | Self-healing oxide film |
| Chlorides / brine | Excellent | Resists pitting and crevice attack |
| Oxidizing acids (e.g. nitric) | Excellent | Stable passive film |
| Reducing acids | Limited | Less resistant than in oxidizing media |
| Chloride stress-corrosion cracking | Excellent | Highly resistant |
The protective titanium-oxide film gives excellent resistance to seawater, chlorides and oxidizing media; resistance is lower in strongly reducing acids unless inhibited.
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-4 (matching) |
| GMAW / MIG | Good | ERTi-4 |
| 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 |
|---|---|---|
| Heat transfer | Plate heat exchangers, condenser tubing | Formability + corrosion resistance |
| Chemical / marine | Pickling baskets, tanks, harsh-environment parts | Corrosion resistance |
| Medical | Implants, surgical instruments | Biocompatibility + formability |
| Aerospace / cryogenic | Airframe and honeycomb parts, cryogenic vessels | Toughness + formability |
| 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-4 | — |
Commercially pure (unalloyed) titanium, high-oxygen highest-strength grade. UNS R50700.
| Grade | Ti % | O max % | Fe max % | Best Used For |
|---|---|---|---|---|
| Titanium Grade 4 | ≥98.9 | 0.40 | 0.50 | Highest-strength CP titanium; strength + formability |
| Titanium Grade 2 | ≥99.0 | 0.25 | 0.30 | Workhorse CP titanium; best overall balance |
| Titanium Grade 3 | ≥99.0 | 0.35 | 0.30 | Higher-strength CP titanium (Grade 3) |
| 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 |




