Everything You Need To Know About Hastelloy C276

Introduce

Alloy C-276 is a nickel-chromium-molybdenum alloy with universal corrosion resistance unmatched by any other alloy. C-276 is also known as Inconel C-276 or Hastelloy C-276 and is an improved wrought version of alloy C in that it usually doesn't need to be solution heat-treated after welding and has vastly improved fabricability. This alloy is resistant to the formation of grain boundary precipitates, specifically in the weld-heat affected zone. This attribute makes Alloy C-276 suitable for use in the as-welded condition.

HASTELLOY C-276 is a nickel-chromium-molybdenum alloy with universal corrosion resistance unmatched by any other alloy. It has outstanding resistance to a wide variety of chemical process environments including ferric and cupric chlorides, hot contaminated mineral acids, solvents, chlorine and chlorine contaminated (both organic and inorganic), dry chlorine, formic and acetic acids, acetic anhydride, sea water and brine solutions and hypochlorite and chlorine dioxide solutions. Alloy C276 also resists formation of grain boundary precipitates in the weld heat affected zone making it useful for most chemical processes in the as-welded condition. It has excellent resistance to pitting and stress corrosion cracking.

HASTELLOY C276 sheet 0.044" thick in the heat-treated condition at 2050°F, rapid quenched, has an average olsen cup depth of 0.48". Alloy C-276 can be successfully fabricated by many methods. The alloy tends to work harden but with the proper care, the alloy is readily hot and cold formed. Complete information on welding, machining and forming is available.

Alloy C-276 has excellent resistance to both localized corrosion and oxidizing or reducing media. Because of its versatility, alloy C-276 can be used where corrosive conditions are likely to occur or in multipurpose plants. Alloy C-276's native corrosion resistant properties extend to a wide variety of chemical process environments, including strong oxidizers such as ferric and cupric chlorides, hot contaminated media (organic and inorganic), chlorine, formic and acetic acids, acetic anhydride, and seawater and brine solutions. It is used in flue gas desulfurization systems because of its excellent resistance to sulfur compounds and chloride ions encountered in most scrubbers. Alloy C-276 has excellent resistance to pitting, stress-corrosion cracking, and oxidizing atmospheres up to 1900 °F (1038 °C). It is also one of the few materials that withstands the corrosive effects of wet chlorine gas, hypochlorite and chlorine dioxide.

Chemical composition of Hastelloy C276

HASTELLOY C276 is a Nickel-chromium-molybdenum wrought alloy that is considered the most versatile corrosion resistant alloy available. This alloy is resistant to the formation of grain boundary precipitates in the weld heat-affected zone, thus making it suitable for most chemical process applications in an as welded condition.

The chemical composition of HASTELLOY(r) C276 is outlined in the following table.

Features of Hastelloy C276

Like other nickel alloys, Hastelloy C-276  is ductile, easy to form and weld, and possesses exceptional resistance to stress corrosion cracking in chloride-bearing solutions (a form of degradation to which the austenitic stainless steels are prone). With its high chromium and molybdenum contents, it is able to withstand both oxidizing and non-oxidizing acids, and exhibits outstanding resistance to pitting and crevice attack in the presence of chlorides and other halides. Furthermore, it is very resistant to sulfide stress cracking and stress corrosion cracking in sour, oilfield environments.

Workability

Hastelloy C-276 can be forged, hot-upset, and impact extruded. Although the alloy tends to work-harden, it can be successfully deep-drawn, spun, press formed or punched. All of the common methods of welding can be used to weld alloy C-276, although the oxy-acetylene and submerged arc processes are not recommended when the fabricated item is intended for use in corrosion service. Special precautions should be taken to avoid excessive heat in-put.

Welding

Gas tungsten-arc welding, gas metal-arc welding, shielded metal-arc (coated electrode) welding, or resistance welding may be used. Minimum heat input consistent with adequate penetration reduces the chance of hot-cracking. Oxyacetylene welding should be avoided due to possibility of carburization. Hastelloy C-276 can be used in the as-welded condition in most chemical and petrochemical process equipment.

Heat-Treatment

Wrought forms of Hastelloy C-276 are furnished in the solution heat-treated condition unless otherwise specified. Alloy C-276 is normally solution heat-treated at 2050 °F and rapid quenched. Parts which have been hot-formed should be solution heat-treated prior to final fabrication or installation, if possible.

Corrosion Resistant

Considered one of the most versatile corrosion resistant alloys available, Hastelloy C-276 exhibits excellent resistance in a wide variety of chemical process environments including those with ferric and cupric chlorides, hot contaminated organic and inorganic media, chlorine, formic and acetic acids, acetic anhydride, seawater, brine and hypochlorite and chlorine dioxide solutions. In addition, alloy C-276 resists formation of grain boundary precipitates in the weld heat affected zone making it useful for most chemical processes in the as-welded condition. This alloy has excellent resistance to pitting and stress corrosion cracking.

What is Hastelloy C276 used for?

Because of its long history of versatility and reliability for corrosion resistance combined with high strength, good formability, weldability, non-magnetic properties, and non-toxicity, Hastelloy C276 is the material of choice for many uses in extreme environments. It’s a valuable material in a wide range of industries, including chemical processing, pollution control, power generation, pharmaceuticals and food processing.

Chemical processing: Hastelloy C276 is widely used in the chemical processing industry due to its excellent corrosion resistance. It is frequently used to resist corrosion from harsh chemicals such as sulfuric acid, hydrochloric acid, and phosphoric acid and chlorine, making it suitable for use in a variety of processing equipment. It is also resistant to corrosion from seawater, making it a valuable material in offshore oil and gas production.

Pollution control: Hastelloy C276 is a great alloy for use in pollution control equipment, such as scrubbers and stacks, due to its resistance to corrosion and high temperatures.

It is often used in flue gas desulfurization systems to help reduce sulfur dioxide emissions from power plants. The alloy is resistant to corrosion from the sulfur-containing compounds that are formed during the scrubbing process.

Power generation: Hastelloy C276 is also used in the power generation industry, particularly in coal-fired power plants. The high temperature and corrosive environment of a power plant can be tough on materials, but Hastelloy C276 is able to withstand these conditions due to its excellent corrosion resistance. This makes it great for power generation equipment such as steam generators and nuclear reactors.

Pharmaceutical: Hastelloy C276 is also used in the pharmaceutical industry due to its ability to resist corrosion from various chemicals and its non-toxic nature. During the production of pharmaceuticals and drugs, the alloy is able to resist corrosion from the harsh chemicals used, as well from hot water and steam. Hastelloy C276 is also used in the pharmaceutical industry for the construction of process equipment such as tanks, pipes, and valves.

Food Processing: Again, thanks to its corrosion resistance and non-toxic nature, Hastelloy C276 is also commonly used in the food processing industry for the construction of food processing equipment such as pasteurizers and sterilisers, storage tanks, pipes, and valves.

In conclusion, Hastelloy C276 is a versatile alloy with excellent corrosion resistance and high strength. Its good weldability and formability make it a convenient choice for a variety of industries, including chemical processing, pollution control, and power generation.