ALLOY800H/HT (Incoly800HT)


ALLOY800 HT is an austenitic high-strength solid-solution Ni-Fe-Cr Alloy with controlled levels of C, Al, Ti, Si and Mg and increased content of (Al + Ti).
A special solution anneal treatment gives highest creep-rupture strength above 700 °C (1290 °F) due to the precipitation of TiC.
Below 700 °C (1290 °F), gamma prime (γ´) precipitates combined with loss of ductility.

  • •excellent creep strength at temperature above 700 °C (1290 °F)
    good resistance to reducing, oxidizing and nitriding atmospheres and to atmospheres which alternate between reducing and oxidizing conditions
    metallurgical stability in long-term application at high temperatures
    For applications where frequent excursions to temperatures lower than 700 °C (1290 °F) during service cannot be excluded or parts of the material are permanently exposed to a temperature below 700 °C (1290 °F), the use of ALLOY800H is recommended.

Stock Form and Sizes

※ ◆1000㎜ ◎2000㎜ ▲3000㎜ ■3500㎜ ●4000㎜ ★2500㎜~3990㎜

Round BarsSpecification: ASTM B408/B564※ ASME SB408/SB564※ ※B564/SB564 Apply to Forged Bar Only

Stock Specification:800H/HT Dual

size 1〜13
size 16〜50
size 55〜135
size 140〜300
Hex barsSpecification:ASTM B446
Nuts and washersSpecification:Nuts JIS B1181 Class1 Washers / JIS B1256 Normal Series Grade.A

※Please enquire about grades and sizes not in stock.

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Sourceable Ex-Stock Material for other Forms from Distributors World-Wide

EquivalentRound BarsPlatePipe/TubeWelding Rod & Wire
MinMax MinMax

*○: Various sizes available in stock. △: Only limited sizes available in stock. ☆: Please contact us for more details.
* We can supply materials and products that comply with various standards including ASTM, ASME, AMS, and NACE standards. Please contact us for more details.

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Corrosion resistance

The high nickel and chromium contents of Alloy800H/HT ensure excellent resistance to oxidation.
The alloys are also very resistant to carburization, nitridation and oxidizing sulphur-bearing atmospheres.
The protective oxide film which is formed is adherent in both static and cyclic conditions of heating and cooling, and resistance to carburization is enhanced when a thin film of oxide is formed on the alloy through pre-oxidation prior to service.
Resistance to hydrogen is excellent and Alloy800H/HT are standard materials used in the production of hydrogen in steam/hydrocarbon reforming processes.


Due to high strength during long periods of service and resistance to carburization and nitridation, ALLOY800H/HT have found many applications in steam/hydrocarbon reforming for components such as: pigtails, headers/collectors/manifolds, transfer piping, catalyst tubes (in lowpressure processes) and quench-system piping.

Typical applications are:
  • • ethylene pyrolysis tubing in convection and radiant sections – resistance to carburization and good mechanical properties
  • • ethylene dichloride cracking tubes ? resistance to carburization and to dry hydrogen chloride and chlorine
  • • cracking tubes used in the production of acetic anhydride and ketene – high strength, resistance to both carburization and the formation of sigma phase
  • • components, e.g. heat exchangers, piping systems etc., in coal conversion plants
  • • steam generator tubing in helium cooled, high temperature reactor systems ? high strength, resistance to helium and to steam

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Chemical composition

min30.019.0bal.   0.300.30 

※The values in the table are for reference only and do not guarantee minimum or maximum values. For further information, please contact us.

Mechanical properties(Round Bar)

 Yield Strength(Mpa)Tensile Strength(Mpa)Elongation(%)Hardness(HB)
ASTM Min Value17045030 
Typical Values at RT24555940140

Above standard values and typical values of Round Bar.
Please contact us with any questions about reference or value of plate and pipe.
※Grade 1
※The values in the table are for reference only and do not guarantee minimum or maximum values. For further information, please contact us.

International Standard Comparison Chart

 MaterialRound BarsPlates/SheetsPipe/Tube
B408 B409B407B163

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Inquiry/Request for information

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