Hastelloy C276 is a nickel-molybdenum-chromium superalloy with an addition of tungsten designed to have excellent corrosion resistance in a wide range of severe environments. The high nickel and molybdenum contents make the nickel steel alloy especially resistant to pitting and crevice corrosion in reducing environments while chromium conveys resistance to oxidizing media. The low carbon content minimizes carbide precipitation during welding to maintain corrosion resistance in as-welded structures. This nickel alloy is resistant to the formation of grain boundary precipitates in the weld heat-affected zone, thus making it suitable for most chemical process application in an as welded condition.

Although there are several variations of the Hastelloy nickel alloy, Hastelloy C-276 is by far the most widely used.
Alloy C-276 is widely used in the most severe environments such as chemical processing, pollution control, pulp and paper production, industrial and municipal waste treatment, and recovery of sour natural gas.

General Properties

Alloy 276 (UNS N10276) is a nickel-molybdenum-chromium-iron-tungsten alloy which is among the most corrosion-resistant alloys currently available. The high molybdenum content imparts resistance to localized corrosion such as pitting. The low carbon minimizes carbide precipitation during welding to maintain resistance to intergranular attack in heat affected zones of welding joints.

Alloy 276 also has good high temperature strength and moderate oxidation resistance although the alloy will eventually form embrittling high temperature precipitates.

Alloy 276 has been available for several years and has been used in ASME Boiler and Pressure Vessel related construction. The alloy is covered in ASME Section VIII Divisions 1 and 2, in numerous product forms.

The alloy is readily fabricated by welding using techniques similar to those used for austenitic stainless steels and other nickel base alloys. Precautions are advisable during fabrication because raising the low carbon and silicon contents of the material may adversely affect important properties.

Forms