Hastelloy Alloy C276 Tubing, Alloy C-276 Pipe

--Corrosion-Resistant Solutions for Harsh Environments

Discover the exceptional corrosion resistance of Hastelloy C-276 tubing and pipes. Learn about key specifications, applications, and selection criteria.

Hastelloy C-276, corresponding to UNS N10276, is a nickel-chromium-molybdenum-tungsten corrosion-resistant alloy. It is often described as a general-purpose material for harsh corrosive environments, a statement that can easily obscure the selection criteria. C-276 can withstand a variety of oxidizing and non-oxidizing acids and has strong resistance to chloride pitting, crevice corrosion, and stress corrosion cracking, although its specific performance depends on the concentration of the medium, temperature, and the stress conditions on the equipment.

This corrosion resistance comes from the combination of its elements. Molybdenum and tungsten enhance the material's resistance to localized corrosion, while chromium helps it cope with oxidizing media. The lower carbon and silicon content reduces the risk of harmful precipitates forming in the weld heat-affected zone, allowing the material to maintain good corrosion resistance even in the welded state. This is also an important reason why C-276 is suitable for manufacturing complex chemical equipment.

Pipe standards need to distinguish between product forms. ASTM B622 is suitable for seamless pipes and tubes, ASTM B619 for welded pipes, and ASTM B626 is mainly used for welded tubes, including heat exchanger tubes, condenser tubes, and general corrosion-resistant tubes. Products are typically delivered in a solution-annealed and descaled state. When purchasing, dimensional tolerances, surface quality, heat treatment records, and hydrostatic or non-destructive testing results should be checked.

C-276 pipes are commonly used in chemical reactors, heat exchangers, towers, and corrosive fluid pipelines. They are also found in flue gas desulfurization, pulp and paper manufacturing, and some acidic oil and gas environments. When dealing with mixed acids, chlorides, or media with fluctuating composition, it often offers more margin than conventional stainless steel, but the final selection should be based on actual corrosion data, design pressure, and operating temperature.