3.7235 is the German material number for a palladium-bearing commercially pure (unalloyed) titanium developed for enhanced corrosion resistance. This datasheet presents the material within the Werkstoff-Nummer (DIN / EN) designation system.
3.7235 has essentially the same composition and mechanical properties as the workhorse pure-titanium grade 3.7035, but with a deliberate addition of about 0.12–0.25% palladium that greatly enhances corrosion resistance. The palladium raises resistance to reducing acids and markedly reduces susceptibility to crevice corrosion, especially in hot chloride-containing media. It is one of the low-alloy titanium materials developed for the chemical industry, offering the same excellent properties as pure titanium together with substantially improved resistance to reducing solutions, and it retains good formability, weldability and biocompatibility.
Typical applications include chemical-processing reactors and heat exchangers handling reducing acids, chlor-alkali and hydrometallurgical equipment, and marine and desalination components requiring the highest corrosion resistance.
| Property | Value | Unit |
|---|---|---|
| Density | 4.51 | g/cm³ |
| Melting point | 1660 | °C |
| Elastic modulus | 105 | GPa |
| Coefficient of thermal expansion (20–100 °C) | 8.6 | µm/m·°C |
| Thermal conductivity (20 °C) | 17 | 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 | — | 0.25 | Residual |
| Oxygen | O | — | 0.20 | Interstitial; strength |
| Carbon | C | — | 0.08 | 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. 3.7235.
| 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 | 105 GPa |
Values per DIN 17850 (mechanically equivalent to 3.7035); not hardenable by heat treatment. Confirm against the inspection certificate (EN 10204).
| 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 the best corrosion resistance of the titanium grades — particularly in hot reducing acids and chloride-bearing media where it strongly resists crevice corrosion.
A palladium-bearing 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 palladium-bearing 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 | Good — bending, drawing |
| Hot forming | ~600–800 °C; protect from contamination; anneal afterward |
| Industry | Typical Components | Key Requirements |
|---|---|---|
| Chemical processing | Reactors, heat exchangers, columns | Reducing-acid / crevice 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 | DIN / EN Standard | Notes |
|---|---|---|
| Sheet, strip and plate | DIN 17860 · W.Nr. 3.7235 | TiPd0.2A |
| Bar, rod and wire | DIN 17850 · W.Nr. 3.7235 | — |
| Seamless / welded tube | DIN 17869 · W.Nr. 3.7235 | — |
| Inspection documents | EN 10204 | — |
Palladium-bearing commercially pure titanium (Ti-0.15Pd). W.Nr. 3.7235 (TiPd0.2A).
| W.Nr. | Pd % | Fe max % | Type | Best Used For |
|---|---|---|---|---|
| 3.7235 | 0.12–0.25 | 0.25 | CP + Pd | Ti-0.15Pd; best corrosion resistance (reducing acids, crevice) |
| 3.7035 | — | 0.25 | CP (unalloyed) | Workhorse CP titanium (base grade) |
| 3.7225 | 0.12–0.25 | 0.20 | CP + Pd | Ti-0.15Pd on softer base (more formable) |
| 3.7065 | — | 0.50 | CP (unalloyed) | Highest-strength CP titanium |
| 3.7105 | — | 0.30 | CP-type alloy | Ti-0.3Mo-0.8Ni; enhanced corrosion (Grade 12) |




