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Is Hastelloy C22 better than C276?
Short answer
C22 is better in oxidising and mixed oxidising-reducing chemistries, thanks to about 22% chromium, and it resists localised corrosion very well. C276 is better in strongly reducing acids, with more molybdenum and tungsten. For many mixed process streams C22 is now the more versatile choice.
Hastelloy C276 vs Hastelloy C22 at a glance
| Property | Hastelloy C276 | Hastelloy C22 |
|---|---|---|
| UNS | N10276 | N06022 |
| EN | 2.4819 | 2.4602 |
| Family | Nickel-chromium-molybdenum (Ni-Cr-Mo) alloy | Nickel-chromium-molybdenum (Ni-Cr-Mo) alloy |
| C (%) | 0.010 max | 0.015 max |
| Cr (%) | 14.5 – 16.5 | 20.0 – 22.5 |
| Ni (%) | Balance | Balance |
| Mo (%) | 15.0 – 17.0 | 12.5 – 14.5 |
| V (%) | 0.35 max | 0.35 max |
| W (%) | 3.0 – 4.5 | 2.5 – 3.5 |
| Fe (%) | 4.0 – 7.0 | 2.0 – 6.0 |
| Tensile strength | 690 MPa (100 ksi) | 690 MPa (100 ksi) |
| Yield strength | 283 MPa (41 ksi) | 310 MPa (45 ksi) |
| PREN | ≈ 68 – 76 | ≈ 65 – 70 |
| Density | 8.89 g/cm³ | 8.69 g/cm³ |
| Magnetic | Non-magnetic. | Non-magnetic. |
| Typical use | Chemical reactors and heat exchangers | Pharmaceutical and fine-chemical reactors |
Which should you choose?
There's no universal "winner": the right choice depends on service conditions, codes and cost. Share your conditions with us for a recommendation.
Typical selection by process
Welding consumables
C22-type filler is often used even on C276 base metal because it is over-alloyed for many environments. Follow the project procedure.
Products in both grades
Related guides, comparisons and articles
Frequently asked questions
Are C22 and C276 covered by the same specifications?
Yes. Both are in ASTM B575 (plate), B574 (rod), B622 (seamless pipe and tube) and B366 (fittings).
Which is more expensive?
Prices are broadly similar and vary with molybdenum, tungsten and nickel markets.
What is the main difference between Hastelloy C276 and Hastelloy C22?
C22 has more chromium (about 22%) for oxidising media, while C276 has more molybdenum and tungsten for strongly reducing acids. Both resist chlorides and pitting exceptionally well.
When should I choose Hastelloy C276?
Reducing acids, sour gas and FGD.
When should I choose Hastelloy C22?
Oxidising and mixed oxidising-reducing chemistries.
Can Hastelloy C276 replace Hastelloy C22?
Only when the design, code and specification allow it. Strength, corrosion resistance and temperature limits differ, so substitution must be approved by the design authority.
Which has better pitting resistance, Hastelloy C276 or Hastelloy C22?
Typical PREN: Hastelloy C276 ≈ 68 – 76, Hastelloy C22 ≈ 65 – 70. A higher PREN generally means better chloride pitting resistance.