3.7025 is the German material number for commercially pure (unalloyed) titanium, the softest and most ductile of the pure titanium grades. This datasheet presents the material within the Werkstoff-Nummer (DIN / EN) designation system.
With a titanium content of about 99.5% and a standard interstitial (oxygen and iron) content, 3.7035 offers the best overall balance of strength, ductility, formability, weldability and corrosion resistance of the unalloyed grades, combined with an excellent strength-to-density ratio. It is moderately stronger than the low-oxygen grade 3.7025 while retaining good formability. The stable, self-healing oxide film gives high resistance to seawater, chlorides and oxidizing media, and the material is readily welded and highly biocompatible.
Typical applications include plate heat exchangers and tube plates, deep-drawn and severely formed components, chemical and marine equipment, and weight-saving structural components.
| 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 (≈99.5%) |
| Oxygen | O | — | 0.20 | Interstitial; strength vs ductility |
| Iron | Fe | — | 0.25 | Residual; standard level |
| Carbon | C | — | 0.06 | Interstitial impurity |
| Nitrogen | N | — | 0.05 | Interstitial impurity |
| Hydrogen | H | — | 0.013 | Interstitial impurity |
Annealed condition, per DIN 17850 / EN reference data for W.Nr. 3.7035.
| Condition | Property | Value |
|---|---|---|
| Annealed | Tensile strength (Rm) | 390–540 MPa |
| Annealed | 0.2% proof strength (Rp0.2) | ≥250 MPa |
| Annealed | Elongation (A5) | ≥22 % |
| Annealed | Hardness | ~160 HV |
| — | Elastic modulus | 103 GPa |
Values per DIN 17850; not hardenable by heat treatment. Confirm against the inspection certificate (EN 10204).
| 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 cool in air to relieve stress and restore ductility after cold work. Protect from oxygen, nitrogen and hydrogen pickup at temperature.
Excellent weldability with inert-gas processes; the weld pool and cooling weld must be fully shielded from atmospheric contamination, which causes embrittlement.
| Welding Process | Applicability | Filler / Consumable |
|---|---|---|
| GTAW / TIG | Excellent | Matching commercially pure titanium filler |
| GMAW / MIG | Good | Matching filler |
| 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, tube plates | Formability + corrosion resistance |
| Chemical / marine | Tanks, harsh-environment parts | Corrosion resistance |
| Lightweight structures | Weight-saving components | Strength-to-density ratio |
| Explosive cladding | Clad composite plates | Bonding + corrosion resistance |
| Product Form | DIN / EN Standard | Notes |
|---|---|---|
| Sheet, strip and plate | DIN 17860 · W.Nr. 3.7035 | Ti99.5 |
| Bar, rod and wire | DIN 17850 · W.Nr. 3.7035 | — |
| Seamless / welded tube | DIN 17869 · W.Nr. 3.7035 | — |
| Inspection documents | EN 10204 | — |
Commercially pure (unalloyed) titanium, standard-oxygen grade. W.Nr. 3.7035 (Ti99.5).
| W.Nr. | Ti % | O max % | Fe max % | Best Used For |
|---|---|---|---|---|
| 3.7035 | ≈99.5 | 0.20 | 0.25 | Workhorse CP titanium; best overall balance |
| 3.7025 | ≈99.6 | 0.15 | 0.15 | Softest CP titanium; max formability (Grade 1) |
| 3.7055 | ≈99.4 | 0.25 | 0.30 | Higher-strength CP titanium (Grade 3) |
| 3.7065 | ≈99.3 | 0.30 | 0.40 | Strongest CP titanium (Grade 4) |
| 3.7235 | ≈99.5 | 0.20 | 0.25 | CP titanium + Pd; enhanced acid resistance (Grade 7) |




