Titanium Grade 7 · UNS R52400 · W. Nr. 3.7235 · Ti-0.15Pd · TA9
Titanium Grade 7 (Ti-0.15Pd) (R52400): composition, properties, fittings and flanges
Titanium Grade 7 (UNS R52400, W. Nr. 3.7235, Chinese TA9) is mechanically identical to Grade 2 but contains 0.12-0.25 % palladium. The palladium shifts the corrosion potential into the noble direction and stabilises the passive film in hot reducing media, markedly improving crevice corrosion resistance in hot chloride brines,…
- UNS
- R52400
- W. Nr.
- 3.7235
- Density
- 4.51 g/cm³ (0.163 lb/in³)
- Key strength
- 345 MPa / 50 ksi
Identification and standards
| Short form | Titanium Grade 7 · UNS R52400 · W. Nr. 3.7235 · Ti-0.15Pd · TA9 |
|---|---|
| Classification | Palladium-enhanced corrosion resistant titanium |
| UNS | R52400 |
| Werkstoff number | 3.7235 |
| Material family | Titanium Alloys |
Chemical composition
| Element | Composition (wt %) | Why it is there |
|---|---|---|
| Titanium (Ti) | Balance | Matrix |
| Palladium (Pd) | 0.12 - 0.25 | Noble metal addition - crevice corrosion resistance |
| Oxygen (O) | 0.25 max | Interstitial strengthener |
| Iron (Fe) | 0.30 max | - |
| Carbon (C) | 0.08 max | - |
| Nitrogen (N) | 0.03 max | - |
| Hydrogen (H) | 0.015 max | Restricted to avoid hydride embrittlement |
| Other elements, each / total | 0.10 max / 0.40 max | - |
Note Single figures are maximum limits unless shown as a range. Always confirm against the heat-specific EN 10204 3.1 certificate supplied with your order.
Mechanical properties
| Tensile strength, min (annealed) | 345 MPa / 50 ksi |
|---|---|
| 0.2 % yield strength, min | 275 MPa / 40 ksi |
| Elongation in 2 in, min | 20 % |
| Typical hardness, annealed | 120 - 200 HB |
| Modulus of elasticity | 105 GPa (15.2 x 10⁶ psi) |
| Beta transus temperature | Approximately 913 °C |
Warning Values depend on product form, section thickness and heat treatment. Larger sections generally achieve lower strength than thin product; always design against the applicable code allowable stress rather than these figures.
Physical properties
| Density | 4.51 g/cm³ (0.163 lb/in³) |
|---|---|
| Melting point | Approximately 1660 °C (3020 °F) |
| Thermal conductivity at 20 °C | 16.4 W/m·K |
| Mean coefficient of thermal expansion, 20-100 °C | 8.6 µm/m·°C |
| Electrical resistivity at 20 °C | 0.42 µΩ·m |
| Typical crevice corrosion limit in chloride brine | Approximately 250 °C |
Specifications by product form
| Bar / rod / billet | ASTM B348 / ASME SB-348 |
|---|---|
| Plate / sheet / strip | ASTM B265 / ASME SB-265 |
| Seamless pipe & tube | ASTM B338 / ASME SB-338, ASTM B861 |
| Forgings & flanges | ASTM B381 / ASME SB-381 (Grade F7) |
| Butt weld fittings | ASTM B363 / ASME SB-363 (WPT7) |
| Welding consumables | ERTi-7 or ERTi-2 depending on joint duty |
| UNS / EN / China | UNS R52400 · EN Ti-0.2Pd / W. Nr. 3.7235 · GB TA9 |
Product forms available
Hangbo supplies this grade in the following forms. Sizes outside the listed range can often be produced to order.
- Seamless pipe and tube for aggressive brine service
- Forged flanges to ASME B16.5
- Elbows, tees and reducers to ASME B16.9
- Heat exchanger tube including crevice-critical locations
Typical applications
- Crevice-prone heat exchanger tube sheets, tube ends and gasketed joints
- Hot concentrated chloride brines in hydrometallurgy and salt production
- Dilute hydrochloric and sulphuric acid handling equipment
- Flue gas scrubber internals with aggressive deposits
- Geothermal brine handling systems
- Pharmaceutical and fine chemical reactors contaminated with reducing acids
Welding, forming and machining
- Welding
- Weld with ERTi-7 filler where maximum crevice resistance is needed in the weld zone; ERTi-2 may be used where service is milder. Standard titanium inert shielding practice applies.
- Forming
- Same excellent cold formability as Grade 2, allowing shop fabrication of complex shells and heads.
- Cost control
- Use Grade 7 strategically - clad plate, loose liners or only the crevice critical components - to limit the palladium cost while solving the localised corrosion problem.
- Machining
- Same practice as Grade 2: sharp tools, low speeds, high feed, flood coolant and no chlorine-bearing cutting fluids.
Buy Titanium Grade 7 (Ti-0.15Pd) from Hangbo
Material is supplied with full heat-number traceability, solution annealing or ageing performed under calibrated furnace control, and an EN 10204 3.1 certificate covering chemical analysis, mechanical properties, heat treatment records and the agreed NDT scope. Positive material identification and third party inspection and test reports from SGS are available for critical service.