What is the difference between Hastelloy c22 and c276?

Shanghai Lion Metal Co., Ltd. Nickel-based Alloy Division

Hastelloy C22 vs C276: Detailed Comparison

Hastelloy C22 and C276 are two prominent members of the Hastelloy family of alloys, recognized for their exceptional corrosion resistance properties in a wide range of aggressive environments. While both alloys exhibit high-performance characteristics, they differ in composition, corrosion resistance, mechanical properties, temperature capabilities, weldability, applications, and cost. This article provides a comprehensive comparison between Hastelloy C22 and C276 to help understand their distinctions and determine their suitability for various industrial applications.

Chemical Composition

The chemical compositions of Hastelloy C22 and C276 are as follows:

ElementHastelloy C22 Composition (%)Hastelloy C276 Composition (%)
Nickel (Ni)5657
Chromium (Cr)2216
Molybdenum (Mo)1316
Tungsten (W)34.5
Iron (Fe)35
Cobalt (Co)2.5
Vanadium (V)0.35
Manganese (Mn)0.5
Silicon (Si)0.08
Carbon (C)0.0150.01
Phosphorus (P)0.02
Sulfur (S)0.020.015

Performance Comparison

Corrosion Resistance

Hastelloy C22 and C276 are renowned for their exceptional corrosion resistance in various environments:

Corrosion TypeHastelloy C22Hastelloy C276
Oxidizing EnvironmentsExcellent resistance to oxidizing acids like nitric acidExcellent resistance to oxidizing acids such as ferric and cupric chlorides
and mixed acids containing nitric acid and chlorides.
Reducing EnvironmentsHighly resistant to reducing media, offering superiorStrong resistance to reducing acids like sulfuric acid and
performance against sulfuric acid, hydrochloric acid,hydrochloric acid
phosphoric acid, and organic acids.
Chloride EnvironmentsExceptional resistance to chloride-induced pitting andSuperior resistance to chloride-induced stress corrosion
crevice corrosion.cracking (SCC) and pitting

Mechanical Properties

Mechanical PropertyHastelloy C22Hastelloy C276
Tensile StrengthHigh with good ductility and toughness.Strong mechanical properties with good fabricability.
Creep ResistanceExcellent at elevated temperatures, maintaining strength andMaintains structural integrity under prolonged exposure to
integrity.high temperatures.
Impact ResistanceGood resistance to thermal fatigue and mechanical stress.Excellent resistance to corrosion-induced cracking and
degradation.

Temperature Capability

Both alloys exhibit robust performance at high temperatures:

Operating TemperatureHastelloy C22Hastelloy C276
Up to about 1250°F (677°C).Suitable for temperatures up to 1250°F (677°C).

Weldability

WeldabilityHastelloy C22Hastelloy C276
Excellent weldability using standard techniques, minimal riskGood weldability using conventional methods, requiring
of weld decay.proper post-weld heat treatment to maintain corrosion
resistance.

Applications

Hastelloy C22 and C276 find applications in various industries due to their corrosion resistance and mechanical properties:

ApplicationsHastelloy C22Hastelloy C276
Chemical ProcessingUsed in reactors, distillation columns, heat exchangersWidely used in chemical processing environments,
including reactors and piping systems.
Pulp and PaperDigesters, bleach plants, evaporatorsBleach plants, digesters, and other pulp and paper
production equipment.
PharmaceuticalPharmaceutical reactors and equipment
Oil and GasEquipment for sour gas wells, offshore platformsDownhole and surface equipment in oil and gas production
environments.
Waste TreatmentPollution control systems, scrubbersWaste treatment plants and pollution control systems.
AerospaceUsed in aerospace applications where corrosion resistance
and high strength are critical.

Cost Considerations

  • Hastelloy C22: Generally more expensive due to its enhanced resistance to a wider range of corrosive environments and superior weldability.
  • Hastelloy C276: Cost-effective option for applications requiring excellent corrosion resistance in challenging environments, making it a preferred choice in many industries.

Conclusion

In conclusion, Hastelloy C22 and C276 are both highly versatile alloys renowned for their corrosion resistance properties and mechanical strength in harsh environments. Hastelloy C22 offers superior resistance to a wide range of acids and chlorides, making it suitable for applications where extensive chemical resistance is required. Hastelloy C276 excels in environments rich in chlorides and oxidizing acids, providing robust protection against stress corrosion cracking and pitting. The choice between these alloys depends on specific application requirements, including the corrosive environment, operating temperatures, mechanical stress, and budget constraints. Understanding these differences enables industries to select the optimal alloy for ensuring durability, reliability, and performance in critical applications.