Q: What’s the difference between Hastelloy C276 and Hastelloy C22?
A: Hastelloy C276 fasteners offer very good resistance to strong reducing corrosive acids, as well excellent stress corrosion cracking resistance and resistance to localized attack. They are renowned for their corrosion resistance to various concentrated, hot acids and reducing environments, and are often used in hot sulfuric and hydrochloric acid applications.
Though very effective in reducing environments, Hastelloy C22 fasteners increase performance in highly oxidizing environments like concentrated Sulfuric acid, Nitric Acid, Phosphoric Acids. Hastelloy C22 alloy has better overall corrosion resistance in oxidizing corrosives than C276 as well as Inconel 625 alloys due to the higher chromium content.
Like C276 screws, Hastelloy C22 fasteners also offer outstanding resistance to pitting and crevice corrosion, as well as stress corrosion cracking. C276 bolts are usable to 1500°F, while C22 is limited to temperatures below 1250° F.