Alloy 800, Alloy 800H and Alloy 800HT

Alloy 800 (UNS N08800), Alloy 800H (UNS N08810), and Alloy 800HT (UNS N08811) 

Description:
Alloy 800 (UNS N08800, NS111), Alloy 800H (UNS N08810, NS112), and Alloy 800HT (UNS N08811) are nickel-iron-chromium alloys designed to resist oxidation and carburization at elevated temperatures. The nickel content, 32%, makes the alloys highly resistant both to chloride stress-corrosion cracking and to embrittlement from precipitation of sigma phase. The general corrosion resistance is excellent. In the solution annealed condition, Alloys 800H and 800HT have superior creep and stress rupture properties.

General Properties:
Alloy 800 (UNS N08800), Alloy 800H (UNS N08810), and Alloy 800HT (UNS N08811) are nickel-iron-chromium alloys designed to resist oxidation and carburization at elevated temperatures. The nickel content, 32%, makes the alloys highly resistant both to chloride stress-corrosion cracking and to embrittlement from precipitation of sigma phase. The general corrosion resistance is excellent. In the solution annealed condition, Alloys 800H and 800HT have superior creep and stress rupture properties. All three versions of the basic Alloy 800 have been approved as materials of construction under ASME Boiler and Pressure Valve Code, Section I-Power Boilers, Section III-Nuclear Vessels, and Section VIII-Unfired Pressure Vessels.

Alloy 800, Alloy 800H and Alloy 800HT are identical except for the higher level of carbon (0.05 to 0.10 percent) in Alloy 800H, and the addition of up to 1.00 percent aluminum + titanium in Alloy 800HT. Alloy 800 is normally used in this service at temperatures to approximately 1100F (593C). Alloy 800H and Alloy 800HT are normally used above approximately 1100F where resistance to creep and rupture is required.

Limiting Chemical Compositions, %, for INCOLOY alloys 800, 800H and 800HT

 ]Available Product Forms: Pipe, tube, sheet, plate, round bar, forging stock and wire.