N08811 / Incoloy 800HT / NS112B Bar/Rod/Wire/Forging/Plate/Strip Ideal For High-pressure And Extreme Environments
Incoloy 800HT (UNS N08811 / NS112B) is a high-temperature nickel-iron-chromium alloy with enhanced creep and rupture strength, designed for long-term structural use above 600°C. It features controlled carbon, aluminum, and titanium content, making it more stable than Incoloy 800H under thermal stress. Known for its excellent oxidation, carburization, and corrosion resistance, 800HT performs well in heat exchangers, furnaces, petrochemical reactors, and pressure vessels. Available in Bar, Rod, Wire, Forging, Plate, and Strip, it is easily fabricated and welded. The alloy maintains mechanical strength under high temperatures and is widely used in power generation, refining, and chemical processing. Approved for use in ASME high-temperature applications, it is ideal for demanding thermal environments.
Chemical Composition Wt.% | % | Fe | C | Si | Mn | S | Cr | Ni | Cu | Ti | Al |
Min | 39.5 | 0.06 | | | | 19 | 30 | | 0.15 | 0.15 |
Max |
| 0.1 | 1 | 1.5 | 0.015 | 23 | 35 | 0.75 | 0.6 | 0.6 |
Physical Constants | Density(g/cm³) | 7.94 |
Melting Range(℃) | 1357-1385°C |
AlloyState | Recovery Strength Reduction (RP0.2) N/mm2 | Tensile Strength Rm N/mm2) | Elongation A5% |
Solid Solution State | 275 | 550 | 30 |
Trade Code
Overview of Incoloy 800HT
Incoloy 800HT is a high-temperature nickel-iron-chromium alloy, developed as an improved version of Incoloy 800H (UNS N08810). The main difference lies in more tightly controlled carbon, aluminum, and titanium levels, providing better creep and rupture strength at elevated temperatures.
Key Features (All Forms)
Enhanced High-Temperature Strength
- Superior creep resistance and stress rupture strength compared to 800 and 800H.
- Optimized for service at temperatures above 649°C (1200°F).
- Approved under ASME Section VIII Division 1 for pressure vessels in high-temperature service.
Excellent Oxidation and Carburization Resistance
- Resists oxidation, carburization, and nitridation in high-heat atmospheres.
- Withstands cyclic heating and thermal fatigue without cracking or scaling.
Great Structural Stability
- Maintains strength and dimensional stability in long-term thermal exposure.
- Ideal for structural components in hot gas environments.
Good Weldability and Fabrication
- Can be welded using standard processes (TIG, MIG, SMAW) with minimal risk of intergranular corrosion.
- Easy to form, machine, and fabricate into complex shapes.
Form-Specific Notes
Bar / Rod
- Used in high-temperature support structures, bolting, shafts, and load-bearing components.
- High creep rupture strength ensures reliability in heat-exposed assemblies.
Wire
- Ideal for welding wire, spring applications, or thermal barrier mesh in high-heat setups.
Forging
- Forged into flanges, valve bodies, heat shields, and tube sheets for high-temp process equipment.
Plate / Strip
- Used for pressure vessels, furnace components, heat exchanger shells, and boiler parts.
- Outstanding stability and resistance to oxidation and scaling.
Common Applications & Industries
- Petrochemical industry: Reformer outlet manifolds, cracker tubes, transfer piping
- Power generation: Superheaters, reheaters, heat recovery systems
- Industrial furnaces: Trays, supports, baskets, muffle parts
- Nuclear and chemical plants: Heat exchanger components, reactor parts
- Gas turbines and exhaust systems


