# Hastelloy C-276: High-Performance Nickel-Chromium-Molybdenum Alloy (UNS N10276)
## Introduction to Hastelloy C-276
Hastelloy C-276 (UNS N10276) is a nickel-chromium-molybdenum alloy known for its exceptional corrosion resistance in severe environments. This superalloy maintains its properties in both oxidizing and reducing conditions, making it a preferred choice for demanding industrial applications.
## Chemical Composition
The unique properties of Hastelloy C-276 stem from its carefully balanced composition:
– Nickel (Ni): 52-62% (base metal)
– Chromium (Cr): 14.5-16.5%
– Molybdenum (Mo): 15-17%
– Iron (Fe): 4-7%
– Tungsten (W): 3-4.5%
– Cobalt (Co): ≤2.5%
– Other elements in smaller quantities
## Key Properties
### Corrosion Resistance
Hastelloy C-276 offers outstanding resistance to:
– Pitting and crevice corrosion
– Stress corrosion cracking
– Oxidizing acids like nitric and phosphoric
– Reducing environments containing sulfuric and hydrochloric acids
### Mechanical Properties
Typical mechanical properties at room temperature:
– Tensile Strength: 690 MPa (100 ksi) min
– Yield Strength: 283 MPa (41 ksi) min
– Elongation: 40% min
– Hardness: Rb 100 max
## Applications
Hastelloy C-276 finds use in numerous industries:
### Chemical Processing
– Reactors and vessels handling corrosive chemicals
– Heat exchangers in aggressive environments
– Piping systems for acid transport
### Pollution Control
– Flue gas desulfurization systems
– Scrubbers and stack liners
– Waste treatment equipment
### Oil and Gas
– Downhole components
Keyword: HastelloyX C-276 UNS N10276
– Offshore platform equipment
– Sour gas processing
## Fabrication and Welding
Hastelloy C-276 can be readily fabricated using standard techniques:
– Forming: Can be cold worked using standard methods
– Machining: Requires slower speeds and heavier feeds than steel
– Welding: Performs well with GTAW, GMAW, and SMAW processes
## Comparison with Other Alloys
While similar to Hastelloy X (UNS N06002) in some respects, C-276 offers superior corrosion resistance in chloride-containing environments. The molybdenum content in C-276 provides better resistance to localized corrosion compared to many other nickel alloys.
## Conclusion
Hastelloy C-276 remains one of the most versatile corrosion-resistant alloys available today. Its combination of excellent chemical resistance, good mechanical properties, and fabricability make it indispensable for critical applications where material failure is not an option.
