5 Things You Should Know About Alloy C-276

Alloy C-276 is a nickel-molybdenum- chromium wrought superalloy with an addition of tungsten. It is the most universally corrosion-resistant material available today. Alloy C-276 also has excellent resistance to pitting, crevice corrosion, and stress corrosion cracking. It is widely used in the chemical process and associated industries.

Alloy C-276 is available in plates, covered electrodes, sheets, strips, billets, bars, wires, pipes, and tubes. Alloy C276 pipe is used in the most severe environments to transfer fluids and fluidized solids. This material is known for its corrosion resistance properties in a wide range of aggressive media.

Here is a list of 5 things you should know about Alloy C-276

· Common Trade Names

Hastelloy C276, Alloy C-276, Nickel C-276; Nickelvac HC-276, Inconel C-276, Nicrofer 5716.

· Applications

Alloy C-276 finds wide applicability across various industries. It is used in digesters and bleach plants in the paper industry. Alloy C-276 is used in chemical processing for multiple components, including heat exchangers, reaction vessels, evaporators, and transfer piping. It is used in components for the recovery of “sour” natural gas. Alloy C-276 is used to manufacture various air pollution control parts, including stack liners, ducts, dampers, scrubbers, stack-gas re-heaters, fans, and fan housings.

Equipment for flue-gas desulfurization plants uses this super-alloy. It is also used in various components which utilize halide or acid catalysts, mixed acid chemical processing, pollution control, pulp and paper production, and municipal waste treatment.

· Characteristics

Alloy C-276 shows exceptional resistance to strong solutions of oxidizing salts, like the ferric and cupric chlorides.

It is one of the few alloys mixes which exhibits resistance to wet chloride gas, hypochlorite, and chlorine dioxide solutions.

Alloy C-276 does not succumb to grain boundary precipitation in welded conditions. Hence it finds extensive use in chemical process applications.

· Resistance to Corrosion

Alloy C-276 shows exceptional resistance to stress corrosion cracking in chloride-bearing solutions, including wet chloride gas, hypochlorite, and chlorine solutions. It also possesses resistance to sulfuric acid, hydrochloric acid, formic acid, acetic acid, chlorides, and solvents. It is much more resistant to stress corrosion cracking than the comparative, austenitic stainless steels. Alloy C-276 exhibits resistance to seawater crevice corrosion. It also has resistance capabilities against phosphoric acid at temperatures below boiling and concentrations lower than 65%. C-276 alloy shows excellent resistance to key, inorganic acids, even in welded form. Because of its high chromium and molybdenum contents, it can withstand both oxidizing and non-oxidizing acids.

· Fabrication and Welding

Alloy C-276 can be hot forged, hot rolled, hot upset, hot extruded, and hot-formed. Hot forming should be done between 1600 and 2250°F (870 and 1230°C), with all heavy forming above 2000°F (1090°C). It can be annealed to optimize the alloy’s corrosion resistance and flexibility. For optimum corrosion performance, cold-worked parts should be re-annealed. Hence, this alloy type can be formed using various cold and hot working processes. Annealing should be practiced at a temperature between 2050°F and 2150°F. A rapid quench should follow this in a protective atmosphere or agitated reducing quench bath.

Alloy C-276 work hardens quickly. However, it can be cold formed again using aggressive methods such as deep drawing, press forming, and punching.

To Conclude:

Alloy C-276 is known for its outstanding corrosion resistance to pitting and crevice attack in the presence of chlorides and other halides and a wide range of aggressive media. It is used in a variety of chemical process environments.

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