Grade 7 Titanium
Unalloyed titanium with palladium, for acids
Typical values for the temper in the title
Grade 7 is Grade 2 titanium with a small palladium addition (0.12–0.25%). Mechanical properties are almost identical, but palladium greatly improves corrosion resistance in reducing acids (hydrochloric, sulfuric) and hot crevice corrosion.
It is used for chemical equipment where Grade 2 fails: heat exchangers, vessels and piping in the chemical industry and hot brines. Palladium makes it expensive, so a cheaper alternative is Grade 12.
Mechanical and physical properties
| Property | Value | Note |
|---|---|---|
| Tensile strength Rm | ≥345 MPa | |
| Yield strength Rp0.2 | ≥275 MPa | |
| Elongation A | ≥20% | |
| Modulus of elasticity E | 103 GPa | |
| Density ρ | 4.51 g/cm³ | |
| Machinability | 55% | relative rating in the site database |
Chemical composition (wt %)
| Element | Range | Role |
|---|---|---|
| Pd palladium | 0.12–0.25 | resistance in reducing acids |
| O oxygen | max 0.25 | strength |
| Fe iron | max 0.30 | |
| Ti titanium | balance |
Ranges and minimum mechanical properties per ASTM B348 (GS Alloy, Rolled Alloys).
Conditions and heat treatment
Unalloyed and lean-alloyed titanium is supplied annealed, which is its service condition.
| Condition | Properties | When to choose it |
|---|---|---|
| Annealed | Rm ≥345, Rp ≥275 MPa | most uses |
| 7H | Rm ≥400 MPa | pressure vessels |
Applications
- Chemical heat exchangers
- Acid vessels and piping
- Hot brines
- Electrolysis equipment
- Chlorine equipment
Fabrication
Welding
Excellent, by TIG with full gas shielding (including the root), like all titanium.
Machining
Low speed, continuous feed and flood coolant. Chips are flammable, so do not let them accumulate.
Corrosion
Highly resistant in seawater, chlorides and oxidizing environments.
Compared with similar materials
| Material | Rm / Rp0.2 | Welding | When it is the better choice |
|---|---|---|---|
| Grade 2 | 340–440 / 275–375 MPa | Excellent — ERTi-2 | Grade 2: cheaper, less resistant in reducing acids · material page |
| Grade 12 | ≥483 / ≥345 MPa | Excellent | Grade 12: a cheaper alternative, stronger · material page |
| Hastelloy C-276 | 690–1000 / 350–460 MPa | Good — ERNiCrMo-4 | Hastelloy C-276: a nickel alloy for acids · material page |
Common mistakes
Choosing Grade 7 where Grade 2 is enough
Palladium is very expensive.
Using titanium in hydrofluoric acid
No titanium grade resists it.
Welding without root shielding
The weld oxidizes and embrittles.
Equivalents, standards and supply
| ASTM | Grade 7 |
|---|---|
| DIN | 3.7235 |
| UNS | R52400 |
| Standards | ASTM B348 / ASTM B265 / ASTM B338 |
| Forms | bar · plate · tube |
| Producers | TIMET · VSMPO |
Learn more
Values are typical and for comparison only. For design, rely on the standard and the mill certificate. Sources: ASTM B265 (sheet and plate), ASTM F136, AMS specifications, producer data sheets, and the METAL HUB materials database.
Updated: October 31, 2026