Hastelloy C-22 and Hastelloy C-276 are two high-performance nickel-based alloys widely used in chemical, marine, and energy industries, particularly in highly corrosive and high-temperature environments. While both alloys offer excellent corrosion resistance, they differ significantly in chemical composition, corrosion behavior, mechanical properties, and application areas.
Hastelloy C-22 vs Hastelloy C-276: In-Depth Comparison
Hastelloy C-22 is a nickel-chromium-molybdenum-tungsten alloy (Ni-Cr-Mo-W) specifically designed to withstand both strong oxidizing and reducing environments. Its high chromium content gives it excellent resistance to highly oxidizing media (such as chloric or nitric acid) while maintaining good performance in reducing conditions.
Hastelloy C-276 is a nickel-molybdenum-chromium-tungsten alloy (Ni-Mo-Cr-W) known for excellent resistance to both reducing and oxidizing conditions, suitable for high-temperature and highly corrosive environments. Its high molybdenum content makes it particularly effective in chloride-containing or alternating oxidizing/reducing environments.
Basic Information and Chemical Composition
| Alloy Grade | Major Composition (wt%) | Typical UNS Number |
| C-22 | Ni 56%, Cr 22%, Mo 13%, W 3%, Fe 3% | N06022 |
| C-276 | Ni 57%, Cr 16%, Mo 16%, W 4%, Fe 5% | N10276 |
C-22’s higher chromium content provides better resistance in oxidizing media, while C-276’s higher molybdenum content gives it superior resistance in reducing environments.
Corrosion Resistance Comparison
| Propriété | C-22 | C-276 |
| Chloride Stress Corrosion Cracking Temp (CPT) | >150°C (>302°F) | >150°C (>302°F) |
| Critical Crevice Corrosion Temperature (CCCT) | 102°C (212°F) | 80°C (176°F) |
| Corrosion Resistance in Wet Chlorine | Superior to C-276 | Lower than C-22 |
C-22 performs better in oxidizing and chloride-containing environments compared to C-276.
Mechanical Properties and Fabrication
| Propriété | C-22 | C-276 |
| Limite d'élasticité (MPa) | 290–450 | 275–450 |
| Résistance à la traction (MPa) | 550–700 | 550–700 |
| Allongement (%) | ≥30 | ≥30 |
| Soudabilité | Excellent, strong intergranular corrosion resistance | Good, may require post-weld treatment |
C-22 offers superior weldability and intergranular corrosion resistance after welding compared to C-276.
Domaines d'application
| Application | C-22 | C-276 |
| Strong Oxidizing Acid Media | Preferred | Usable, but slightly inferior |
| Chloride Environments | Preferred | Usable, slightly inferior |
| High Temperature Environments | Bien | Excellent |
| Welded Structures | Preferred | Usable, post-weld care needed |
C-22 is best suited for oxidizing and chloride-rich environments, while C-276 excels in high-temperature and reducing conditions.
Price and Economic Considerations
| Alloy Grade | Price Range (USD/kg) |
| C-22 | 45–70 |
| C-276 | 60–90 |
C-22 is generally lower in cost but may require performance trade-offs in certain environments.
Conclusion and Recommendation
| Selection Factor | Recommended Alloy |
| Strong Oxidizing Environment | C-22 |
| High-Temperature Service | C-276 |
| Welded Structures | C-22 |
| Considérations relatives aux coûts | C-22 |
Selecting the appropriate alloy should be based on the specific operating conditions to ensure long-term reliability and optimal performance.
Common Products
- Pipes & Tubes
- Raccords
- Plates, strips, and bars
- Valves and pump components
- High-corrosion-resistant equipment components
Normes pertinentes
- ASTM B574 (bars)
- ASTM B622 (plates)
- UNS N10276
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