HC-276is well known for its outstanding corrosion resistance in a wide range of extremely aggressive media and very punishing environments. It is truly a superalloy amongst the high nickel-chromium-molybdenum materials, and is considered the preeminent alloy for the chemical industry.
It resists many of the most severe media encountered in chemical processing, including reducing and oxidizing acids. It has exceptional resistance to sulphuric acid and hydrochloric acid, plus excellent resistance to phosphoric acid. The controlled amount of tungsten and very high content of molybdenum :(up to 17%) C276 has excellent resistance to stress corrosion cracking, and pitting. Alloy C276 is also almost unmatched in its resistance to seawater especially under crevice conditions which would induce attack in other commonly used materials such as 316 stainless steel, 6MO stainless and monel. Hastelloy C276 is also favoured by the oil and gas industry because of its ability to handle “sour”( natural) gas, combined with its corrosive resistance by seawater. In such environments it has become very popular in the manufacturer of valves and pumps.
Due to the high content of chromium and nickel in the alloy, tungsten and cobalt are added. C276 is difficult to process and the raw materials are expensive, but Hastelloy can produce surprisingly high-quality compression fittings and valves.