Nickel and nickel alloys · Alloy 800HT / Incoloy 800HT / UNS N08811 / 1.4959
Incoloy 800HT (UNS N08811 / 1.4959): Engineering Overview of High-Temperature Alloy
Engineering Technical Passport for High-Temperature Alloy Incoloy 800HT
| Product Formats | Alloy Marking | Key Specifications | Key Specifications | |
|---|---|---|---|---|
| Sheet, Plate, Strip, Bar, Flat Bar, Hexagon Bar, Wire, Seamless and Welded Pipes, Forgings | Alloy 800HT, Incoloy 800HT, Nicrofer 3220 HP, UNS N08811 | ASTM | ASME | Equivalents |
| Sheet, Plate, Strip, Bar, Flat Bar, Hexagon Bar, Wire, Seamless and Welded Pipes, Forgings | Alloy 800HT, Incoloy 800HT, Nicrofer 3220 HP, UNS N08811 | B163, B366, B407, B408, B409, B514, B515, B564, B751, B775, B924 | SB 163, SB 366, SB 407, SB 408, SB 409, SB 514, SB 515, SB 564, SB 751, SB 775, SB 924 | W.Nr. 1.4959, DIN 17459, 17460, ISO 4955A, 6207, 6208, 9723, 9725 |
| Sheet, Plate, Strip, Bar, Flat Bar, Hexagon Bar, Wire, Seamless and Welded Pipes, Forgings | Alloy 800HT, Incoloy 800HT, Nicrofer 3220 HP, UNS N08811 | B163, B366, B407, B408, B409, B514, B515, B564, B751, B775, B924 | SB 163, SB 366, SB 407, SB 408, SB 409, SB 514, SB 515, SB 564, SB 751, SB 775, SB 924 | W.Nr. 1.4959, DIN 17459, 17460, ISO 4955A, 6207, 6208, 9723, 9725 |
Incoloy 800HT alloy (UNS N08811), supplied by EV Group China, is an austenitic iron-nickel-chromium based material optimized for operation at extremely high temperatures. Precise control of the chemical composition, particularly carbon, aluminum, and titanium, ensures exceptional microstructural stability during prolonged heating above 600°C. This guarantees excellent creep resistance, as well as resistance to high-temperature oxidation, carburization, and sulfidation.
Chemical Composition of UNS N08811 Alloy (mass %)
| C | 0.06-0.10 |
|---|---|
| Si | <1.0 |
| Mn | <1.5 |
| P | <0.045 |
| S | <0.015 |
| Cr | 19.0-23.0 |
| Ni | 30.0-35.0 |
| Ti | 0.15-0.60 |
| Al | 0.15-0.60 |
| Cu | <0.75 |
| Fe | >39.5 |
Engineering Note: The total content of alloying elements Al + Ti is strictly regulated within the range of 0.85-1.20%. The increased carbon (C) content compared to grade 800H is a key factor in achieving significantly higher long-term strength and creep resistance.
Creep Rupture Strength (10,000 hours)
| Temperature | 650 °C | 705 °C | 760 °C | 870 °C | 980 °C |
|---|---|---|---|---|---|
| Rupture Strength (ksi) | 24.0 | 15.0 | 10.0 | 4.7 | 2.0 |
| Rupture Strength (MPa) | 165 | 105 | 70 | 32 | 14 |
Key Physical-Thermal Parameters
The alloy density is 7.94 g/cm³. Its outstanding structural stability makes Incoloy 800HT a preferred choice for manufacturing critical components of industrial furnaces and reactors operating under high loads.
Corrosion Resistance and Industrial Applications
The high concentration of nickel and chromium in Nicrofer 3220 HP alloy forms a dense, well-adhered oxide film on the surface, which provides effective protection against aggressive oxidizing environments. The adhesion strength of this protective layer is critically important for parts subjected to cyclic thermal loads. EV Group China recommends this alloy for the following industries:
- Components for hydrocarbon reforming and hydrogen production plants: pigtail coils, headers, catalytic reactor tubes.
- Parts for pyrolysis and ethylene furnaces where high resistance to carburization is required.
- High-temperature heat exchange systems and coal gasification equipment.
- Superheater elements in power plants, including helium nuclear reactors.
Technological Recommendations for Welding Operations
Incoloy 800HT demonstrates excellent weldability with standard methods, including TIG/GTAW and MIG/GMAW welding. To maintain equivalent strength of the weld joint with the base metal, it is necessary to use nickel-based filler materials. Recommended grades: ERNiCr-3 welding wire or ENiCrFe-3 electrodes.