Specifications

Chemical composition and mechanical properties

Phosphorus and sulphur limits as given in the standards.

Values for solution-annealed material as given in ASTM B575.

Background and equivalents are on the Hastelloy C276 page.

Where Hastelloy C276 plate is used

Chemical and pharmaceutical: reactors, columns, heat exchangers and storage for hydrochloric and sulphuric acids, chlorinated organics, and processes with chloride contamination. Flue-gas desulphurisation: absorber inlets, outlet ducts, dampers and stack liners exposed to acidic, chloride-rich condensate. Pulp and paper: bleach plant equipment. Waste treatment and incineration: scrubbers and quench vessels. Oil and gas: sour-service vessels and clad equipment.

Solid, clad or lined construction

Because C276 is expensive, large vessels and ducts are often made from carbon steel with a C276 layer – roll-bonded or explosion-clad plate, weld overlay, or wallpaper lining of thin C276 sheet welded to the steel. Thin sheet in the range used for wallpaper linings is a common requirement for FGD and incinerator ducts. Solid plate is used for smaller vessels, tube sheets, internals and where the whole thickness is exposed. Please mention the construction method with the enquiry so the thickness and finish can be matched.

Fabrication

C276 plate is cut by plasma or water-jet and sheet by shearing or laser. It forms well cold, though it work-hardens quickly; hot forming must be followed by solution annealing and rapid cooling. It is welded with ERNiCrMo-4 filler using low heat input and low interpass temperature, and can be used as welded in most services because of its low carbon and silicon. Fabrication areas should be kept clean and separate from carbon steel.

Testing

For critical chemical service, plates may be ordered with an intergranular corrosion test to ASTM G28 to confirm correct solution annealing, ultrasonic testing of thick plate, and positive material identification. The mill test certificate reports chemistry, mechanical properties and heat treatment for each heat.

Ordering Hastelloy C276 plates

Please give the specification, thickness, plate or sheet size or cut sizes, quantity, construction (solid, clad or lining), and any testing or inspection requirement. Sheets are packed flat on pallets with interleaving and plates on wooden skids; each piece is marked with grade, specification, heat number and size.

C276 compared with other plate alloys

For less severe conditions, SS 904L, SMO 254, Alloy 20 and Incoloy 825 plates are lower-cost options. Hastelloy C22 plate is preferred where oxidising species dominate or conditions alternate, and Inconel 625 where strength and seawater resistance are the priority. C276 remains the standard choice for hot, reducing, chloride-contaminated acids and wet chlorine, where its high molybdenum and tungsten give the widest safety margin.

Applications and related products

Hastelloy C276 sheets and plates are used in chemical and pharmaceutical plants, FGD systems, bleach plants, waste treatment and sour gas equipment. Other Hastelloy alloys are on the Hastelloy sheets and plates page and all materials on the plates page.