Hastelloy C276 is today known as a universally corrosion resistant material and is used in various environments from moderately oxidizing to strong reducing conditions. The limiting factor when dealing with strong oxidizing environments is the low Cr content which indicates that hot and concentrated nitric acid environments are not required. This alloy has exceptional resistance to acid chlorides, formic & acetic acids, wet chloride gas, chlorine solutions, sulfuric acid & hydrochloric acid, solvents, acetic anhydride and hypochlorites. It has high resistance to phosphoric acid at all temperatures below boiling and at concentrations lower than 65%. Hastelloy C276 has high resistance to corrosion by seawater especially under crevice conditions that induce attack in other commonly used materials. This alloy also has high resistance to pitting that is localized corrosion.

The low carbon content in Hastelloy C276 minimizes carbide precipitation during welding to maintain resistance to intergranular attack in heat effected zones of weld joints. This alloy has excellent high temperature strength and moderate oxidation resistance however the embrittling high temperature precipitates will occur eventually. Hastelloy C276 is widely used in chemical processing industries in reaction vessels, transfer piping, evaporators and heat exchangers. It is used in pollution control (FGD) in ducts, fans, stack liners, dampers and fan housings. This alloy is also used in various other applications including pickling tanks and pickling hooks. Hastelloy C276 exhibits high performance in oilfield applications especially in the recovery and handling of “sour” natural gas that contains hydrogen sulfide, carbon dioxide and chlorides. It is highly resistant to these environments due to its high chromium, nickel and molybdenum content.

Key features of Hastelloy C276 alloy are

• It is resistant to wet chloride gas, hypochlorite and chlorine dioxide solutions.
• It has high resistance to strong solutions of oxidizing salts such as ferric and cupric chlorides.
• It is not prone to grain boundary precipitation in the as welded condition and is suitable for numerous chemical process applications.

Hastelloy C276 alloy has its applications in

• Components exposed to sour gas
• Sulfuric acid reactors
• Equipment for processes utilizing halide or acid catalysts
• Equipment for flue-gas desulfurization plants
• Organic chloride process equipment
• Digesters and bleach plants in the paper industry
• Heat exchangers, evaporators, filters and mixers used in sulfuric acid environments

Hastelloy C276 is especially effective in Scrubber (FGD) applications where it is able to withstand the higher chloride environments before the onset of localized corrosion. Hastelloy C276 is resistant to chloride-induced stress corrosion cracking due to its high nickel content. This alloy performs excellently in oxidizing, non-oxidising and mixed acids media due to its high molybdenum and chromium contents. The high molybdenum and chromium contents also allow this alloy to exhibit excellent resistance to pitting and crevice corrosion attack. The development of pits is inhibited by the addition of tungsten. Hastelloy C276 is appropriate to use for off-shore applications where hydrogen-sulphide (H2S) stress corrosion cracking resistance is necessary. Numerous industries have started using this alloy as it is one of the most corrosion resistant alloys in aggressive or corrosive environments.