Hastelloy C22 and C276 are both nickel-based alloys with excellent corrosion resistance, but they have some differences in their composition and properties. Here are the main differences:

Composition: Hastelloy C22 has a higher chromium content (20-22%) compared to Hastelloy C276 (14-17%). C22 also has a higher molybdenum content (12.5-14.5%) compared to C276 (15-17%). C276, on the other hand, has a higher tungsten content (3-4.5%) compared to C22 (2.5%).

Corrosion Resistance: Both alloys have excellent resistance to a wide range of corrosive environments, including oxidizing and reducing acids, chloride-containing media, and seawater. However, C22 has better resistance to pitting, crevice corrosion, and stress corrosion cracking in some aggressive environments.

Temperature Range: C22 has a slightly lower maximum operating temperature (around 1250°C or 2280°F) compared to C276 (around 1350°C or 2460°F). This makes C276 more suitable for high-temperature applications.

Weldability: Hastelloy C22 is generally considered easier to weld compared to C276. It has better weldability and is less prone to sensitization during welding, which can cause corrosion issues.

Applications: Hastelloy C22 is often preferred in applications involving aggressive chemical environments, such as chemical processing, pollution control, and pharmaceutical industries. Hastelloy C276 is commonly used in oil and gas, petrochemical, and power generation industries, where higher temperatures and mechanical strength are required.

It is important to consider the specific requirements of your application and consult with materials engineers or experts to determine the most suitable alloy for your needs.