Titanium Grade 2 vs Grade 7 vs Grade 12 for heat exchangers
Grade 2 commercially pure titanium is the standard choice for condenser and heat exchanger tube. Grade 12 and Grade 7 are upgraded for hot chloride service where crevice corrosion is a risk: Grade 12 adds molybdenum and nickel and is stronger, while Grade 7 adds palladium and gives the highest crevice corrosion resistance at a higher price.
Titanium grades compared
| Grade | Composition | Min. tensile / yield (MPa) | Typical use |
|---|---|---|---|
| Grade 1 | Commercially pure, softest | 240 / 138 | Where maximum formability is needed |
| Grade 2 | Commercially pure | 345 / 275 | Standard condenser and heat exchanger tube |
| Grade 3 | Commercially pure, higher strength | 450 / 380 | Higher-pressure tube and pipe |
| Grade 7 | Ti-0.15Pd | 345 / 275 | Severe hot chloride and reducing acid service |
| Grade 9 | Ti-3Al-2.5V | 620 / 483 | High-strength tube |
| Grade 12 | Ti-0.3Mo-0.8Ni | 483 / 345 | Hot brine and chloride service, higher strength |
| Grade 16 | Ti-0.05Pd | 345 / 275 | Lower-cost alternative to Grade 7 |
How to choose
- Seawater or cooling water condensers: Grade 2 is the usual specification and performs well.
- Hot brines and chloride process streams: Grade 12 resists crevice corrosion better than Grade 2 and is stronger, so it is a common upgrade.
- The most aggressive chloride or reducing acid service: Grade 7, or Grade 16 where a lower palladium content is acceptable.
- Where strength matters more than formability: Grade 3 or Grade 9.
The final grade should come from the plant’s corrosion engineer or the exchanger designer. Stage Metals supplies all of these grades made to order in South Africa as seamless tube to ASTM B338 and pipe to B861, and welded pipe to B862. See our titanium tube supply page.
Common questions
Is Grade 12 better than Grade 2?
For hot chloride service, yes: it resists crevice corrosion better and is stronger. For ordinary cooling water condensers, Grade 2 does the job at lower cost.
Why is Grade 7 more expensive?
Grade 7 contains palladium, a precious metal. Grade 16 uses less palladium and is often a more economical alternative with similar corrosion performance.
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