What is C276 pipe made of?
Alloy C-276 is a nickel-chromium-molybdenum solid-solution strengthened superalloy with a nominal chemical composition of 57% nickel, 16% chromium, and 16% molybdenum, with added iron, tungsten, and cobalt. It is commonly known by the trade name Hastelloy C-276 and the common name UNS N10276. C-276 is often used in extremely corrosive environments that other alloys cannot withstand.
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Corrosion graphics
Corrosion resistance
Alloy C-276 is one of the most corrosion-resistant alloys. The nickel, chromium and molybdenum in Alloy C-276 present a powerful triple threat to nearly all forms of corrosion. C-276 has excellent resistance to reducing and oxidizing acids, including sulfuric acid, hydrochloric acid, and acetic acid. It also performs well in seawater, chloride, wet chlorine, oxidizing salts and hypochlorite. The molybdenum and tungsten content prevents various forms of localized corrosion, including pitting, crevice corrosion and chloride stress corrosion cracking. C-276 has excellent oxidation resistance at high temperatures up to 1900°F (1038°C). C-276 is not recommended for use in extreme oxidizing environments such as those presented by concentrated hot nitric acid.
Operating temperature
High temperature resistance
C-276 resists oxidation at temperatures up to 1900°F (1038°C).
Mechanical behavior
Mechanical behavior
In the annealed condition, C-276 has a yield strength of 41 ksi (345 MPa). However, higher strength can be obtained through the Pilger process. C-276 maintains excellent toughness at low temperatures.
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heat treatment
C-276 cannot be strengthened by heat treatment. C-276 is typically solution annealed at 2050°F (1121°C) and then rapidly cooled.
Processability
Workability
C-276 can be thermally processed from 1600°F - 2250°F (870°C - 1230°C). It is recommended to anneal after hot working. Cold forming is possible, but its work hardening rate is high, so intermediate annealing may be required.
Application areas
C-276 is a workhorse in the chemical processing industry and is widely used in the oil and gas industry due to its corrosion resistance in a variety of corrosive substances. In the upstream oil and gas sector, C-276 is used as tubing, casing or lining in corrosive sour service environments with high concentrations of H2S, CO2 and chlorides. It is also used in other industries that experience harsh environments, including the pharmaceutical and paper industries. C-276 is used in valves in cryogenic applications and has been used in superconductors at temperatures as low as -455°F (-271°C).
CRA offers specialty alloy C-276 seamless tubing for a variety of industries and applications, including:
Severely corrosive oil and gas wells containing CO2, H2S, SO (elemental sulfur) and chlorides
Chemical Processing Paper and Pulp Industries Sand Screens Basics Piping Pipes, Casings and Liners VITS Well Packers Piping Pharmaceuticals Super Conductors Geothermal
