Hastelloy C276 vs. Hastelloy C22 Fasteners – Which One Should You Choose?

The Hastelloy family, developed by Haynes International, is a well-regarded group of corrosion-resistant metal alloys primarily used in aggressive environments. When it comes to selecting fasteners for high-temperature or highly corrosive settings, such as chemical processing or marine applications, choosing the correct alloy can make a significant difference in performance and longevity. This blog explores two popular variants—Hastelloy C276 and Hastelloy C22—to help you make an informed choice between them.

What is Hastelloy?

Hastelloy is a trademarked series of corrosion resistant metal alloys created by Haynes International. These alloys are known for their outstanding resistance to chemical degradation, especially in severe industrial and marine conditions. Commonly used in aerospace, chemical processing, and pollution control systems, Hastelloy alloys provide exceptional durability and reliability in some of the harshest environments on Earth.

Hastelloy C276 Fasteners

Chemical Composition

Hastelloy C276 is a Nickel-Molybdenum-Chromium alloy that also includes small amounts of iron and tungsten. This combination enhances its structural integrity and corrosion resistance, particularly in environments involving reducing agents.

Key Properties

One of the standout features of C276 fasteners is their exceptional resistance to both strong oxidizing and reducing agents. They are very efficient in demanding conditions that include wet chlorine gas, hydrochloric acid, sulfuric acid, and organic acids such as formic, and acetic acid. C276 fasteners also have great resistance to localized corrosion types including pitting, crevice corrosion, and stress corrosion cracking.

Common Applications

C276 fasteners are widely used in industries that demand top-notch corrosion resistance. Common applications include waste treatment facilities, the pulp and paper industry, marine engineering structures, and various chemical processing units.

Hastelloy C22 Fasteners

Chemical Composition

Hastelloy C22 is a Nickel-Chromium-Molybdenum alloy that also incorporates iron and tungsten. While similar to C276, its formulation is designed to offer enhanced resistance in oxidizing environments.

Key Properties

C22 fasteners are superior in resisting oxidizing agents more than C276. They provide excellent protection against a wide range of acids and other harsh chemicals. Their superior resistance to pitting and crevice corrosion makes them the best for those applications where oxidizing media are of critical concern.

Common Applications

Typical uses of Hastelloy C22 fasteners include flue gas scrubbers, pickling systems, waste incinerators, and pollution control systems. These applications often involve high concentrations of oxidizing chemicals, making C22 an excellent material choice.

Hastelloy C276 vs. Hastelloy C22: Head-to-Head Comparison

Which One Should You Choose?

If your application is under severely reducing conditions or a wide variety of chemicals, Hastelloy C276 fasteners provide the flexibility and toughness needed. On the other hand, if strongly oxidizing chemicals are being encountered and greater resistance to crevice corrosion and pitting are needed, Hastelloy C22 fasteners are more suitable. Considerations such as the particular chemical exposure, operating temperature range, and manufacturing requirements should also shape your choice. Understanding the nature of your application will help ensure long-term reliability and performance.

Conclusion

Both Hastelloy C276 and C22 fasteners are good options for severe environments, but both excel under varying chemical conditions. Your choice should align with your specific industry’s requirements and the types of chemicals involved. For tailored solutions and expert recommendations, it’s always best to consult with a reliable hastelloy fastener supplier who understands the nuances of both materials and can guide you to the best fit for your project.