Microstructure
Alloy 800H and 800HT, like Incoloy 800, are austenitic solid-solution alloys. Their microstructure typically contains titanium nitrides, titanium carbides, and chromium carbides.
Characteristics
Key features of Alloy 800H:
Good creep-rupture strength at temperatures above 600℃ (1110℉), maintaining ductility even during prolonged use at temperatures below 700℃, thanks to the limitation of (Ti+Al) content to a maximum of 0.7%.
Excellent resistance to reducing, oxidizing, nitriding atmospheres, and fluctuating environments between oxidation and reduction.
Metallurgical stability for long-term high-temperature applications.
Key features of Alloy 800HT:
Outstanding creep strength at temperatures above 700℃. However, if frequent exposure to temperatures below 700℃ is expected, Incoloy 800H is recommended instead.
Excellent resistance to reducing, oxidizing, and nitriding atmospheres, and environments with alternating oxidation-reduction conditions.
Metallurgical stability for long-term high-temperature use.
Corrosion Resistance
Alloy 800, 800H, and 800HT share the same nickel, chromium, and iron composition, which results in similar corrosion resistance.
High nickel and chromium content provides exceptional oxidation resistance.
Compared to Alloy 800, 800H and 800HT can be used at higher temperatures while maintaining superior strength.
These alloys exhibit excellent resistance to carburization, nitridation, and sulfur-bearing atmospheres at elevated temperatures.
Incoloy 800H and 800HT offer outstanding resistance to hydrogen embrittlement.
Applications
Alloy 800H and Alloy 800HT are widely used in:
Steam/hydrocarbon reforming – Used in transfer piping, catalyst systems (low-pressure processes), and quench-system piping.
Cracking tubes for acetic anhydride and ketene production – Provides high strength, resistance to carburization, and protection against dry hydrogen chloride and chlorine.
Coal conversion plants – Used in heat exchangers, piping systems, and other critical components.
We have products:
ASTM B407 / B829 Inc 800 / 800H / 800HT Nickel Alloy Seamless Pipe; ASTM A564 Alloy 800 / UNS N08800 Nickel Alloy Slip On Flange; Nickel Alloy Tube Seamless ASTM B407 / B829 Inc Alloy 800 / 800H / 800HT Tube; Incoloy 800/800H/800HT Pipe Fittings;