Incoloy 800HT (UNS N08811 / W.Nr. 1.4959)

Incoloy 800HT (UNS N08811 / W.Nr. 1.4959) nickel-iron-chromium alloys that have the same basic composition as INCOLOY alloy 800 but with significantly higher creep-rupture strength. The higher strength results from close control of the carbon, aluminum and titanium contents in conjunction with a high temperature anneal. Used in chemical and petrochemical processing, power plants for super-heater and reheater tubing, industrial furnaces and heat-treating equipment.

Equivalent Grades

Incoloy 800HTNS1102
Incoloy 800HTN08811X10NiCrAlTi32-201.4959NA15H

Chemical Composition, %

Incoloy 800HT0.06-0.10≤0.10≤3.00≤0.03≤0.0219.0-23.030.0-35.00.25-1.200.15-0.60≥39.5

Typical Physical and Mechanical Properties (RT, Solution annealed)

Density, g/cm3Melting Point, ℃Tensile Strength, MPaYield Strength, MPaELongation, %Hardness, HB

Available Products and Specifications

Rod, Bar, Wire and ForgingsASTM B408/ASME SB408, ASTM B564/ASME SB564, ISO 9723/9724/9725
Plate, Sheet and StripASTM A240/A480/B409/B906/ASME SA240/SA480/SB409/SB906, ISO 6208
Pipe and TubeASTM B163/ASME SB163, ASTM B407/B829/ASME SB407/SB829, ASTM B514/B775/ASME SB514/SB775, ASTM B515/B751/ASME SB515/SB751, ISO 6207
Welding Product
OthersASTM B366/ASME SB366(Fittings)


  • Resistance to prolonged exposure to elevated temperatures
  • Excellent resistance to oxidation, sulfidation, and carburization
  • Added Carbon and annealing treatment allows for higher creep and rupture properties above 600℃
  • Resistant to high temperature corrosion
  • Readily machined by standard methods
  • Best joined/welded using products for high temperature situations
  • Resistance to aqueous corrosion at moderate temperatures


  • Chemical and Petrochemical Processing—process equipment for the production of ethylene, ethylene dichloride, acetic anhydride, ketene, nitric acid and oxy-alcohol
  • Petroleum Refining—steam/hydrocarbon reformers and hydrodealkylation units
  • Power Generation—steam super-heaters and high temperature heat exchangers in gas-cooled nuclear reactors, heat exchangers and piping systems in coal-fired power plants
  • Thermal Processing Fixtures—radiant tubes, muffles, retorts and fixtures for heat-treating furnaces