Comparison between Alloy 800H and Incoloy 800HT alloy tubing

800H alloy tubing and Incoloy 800HT seamless tubing (UNS N08810/N08811) are two similar high-temperature iron-nickel-chromium alloys, but 800HT alloy tubing exhibits superior creep strength and stress rupture strength due to stricter control of carbon content (0.06-0.10% vs. 0.05-0.10% for 800H) and higher, restricted levels of aluminum (Al) and titanium (Ti) (0.85-1.20%). This makes 800HT alloy tubing more suitable for extreme high-temperature environments (up to 925°C), while 800H tubing is suitable for lower high-temperature ranges (above 650°C). Crucially, 800HT tubing is a more precisely controlled version of 800H tubing, with its composition always within the range of 800H tubing, but possessing superior high-temperature mechanical properties. Therefore, these two alloys are often dual-certified.

What is Alloy 800H material?

Alloy 800H is an austenitic heat-resistant nickel-iron-chromium solid solution alloy, in which the content of carbon, aluminum, titanium, silicon, and manganese, as well as the content of (Al + Ti), are strictly controlled.

What is Inconel 800H tubing?
Inconel 800H tubing is a pipe made from a nickel-iron-chromium high-temperature alloy (Incoloy 800H). Its core characteristic is that, through a higher carbon content (0.05-0.10%) and stabilization treatment, it provides excellent creep resistance, carburization resistance, and high-temperature oxidation resistance at temperatures up to approximately 815°C. It is designed for extreme environments requiring long-term exposure to high temperatures, high pressures, and thermal cycling, such as petrochemical cracking furnace tubes, high-temperature heat exchangers, industrial heaters, and nuclear power plant steam generators. It is particularly suitable for critical piping applications requiring high-temperature pressure resistance and thermal fatigue resistance, making it one of the top-tier piping materials in high-temperature industrial fields.

What is Inconel 800HT tubing?
Incoloy 800HT tubing is a pipe made from Incoloy 800HT alloy. Its core characteristic is that, through precise control of carbon, aluminum, and titanium content and stabilization treatment, it provides optimal creep resistance, carburization resistance, and high-temperature oxidation resistance at temperatures up to approximately 815°C, while also possessing extremely high high-temperature strength and long-term stability. It is designed for extreme environments requiring long-term exposure to high temperatures, high pressures, and severe thermal cycling, such as petrochemical cracking furnace tubes, industrial heaters, high-temperature heat exchangers, and nuclear power plant steam generators. It is a top-tier piping material choice for high-temperature pressure and creep-resistant applications.

800H Pipe VS 800HT Pipe : Chemical Composition

Element	Incoloy 800H	Incoloy 800HT
Ni	30.0 – 35.0
Cr	19.0 – 23.0
Fe	Bal. (min. 39.5)
C	0.05 – 0.10	0.06 – 0.10
Mn	≤ 1.50
Al	0.15 – 0.60
Ti	0.15 – 0.60
Al + Ti	0.30 – 1.20	0.85 – 1.20

incoloy 800H VS 800HT Tube: Mechanical Properties

Property	Incoloy 800H	Incoloy 800HT
Tensile Strength (MPa)	≥ 520	≥ 550
Yield Strength (0.2% Offset) (MPa)	≥ 205	≥ 240
Elongation (%)	≥ 30
Hardness	≤ 190
Density	7.94g/cm³
Melting Range	1357−1430℃
Stress Rupture (10,000 hr @ 600℃)	Good	Higher Guaranteed

Main applications of Incoloy 800H and Incoloy 800HT

Environment	Incoloy 800H	Incoloy 800HT
High Heat	Furnaces, Heat Exchangers	Power Generation
Chemical Stress	Mildly corrosive, high temp	Chemical Processing
Pipe System	General high temp pipes	Critical high stress fittings