Alloy 800H / 800HT
UNS N08810 / N08811
Overview
Iron-nickel-chromium alloy engineered for long-term high-temperature service with exceptional creep and rupture strength. 800H (annealed, 0.05-0.10% C) provides controlled grain size for creep resistance up to 815°C. 800HT (fine-grain, Al+Ti enhanced) extends service to 980°C. A more economical alternative to nickel-based superalloys for many petrochemical and power generation applications.
Chemical Composition (wt%)
| Element | Min | Max |
|---|---|---|
| Ni (Nickel) | 30 | 35 |
| Cr (Chromium) | 19 | 23 |
| Fe (Iron) | 39.5 | — |
| Al (Aluminum) | 0.15 | 0.6 |
| Ti (Titanium) | 0.15 | 0.6 |
| C (Carbon — 800H) | 0.05 | 0.1 |
| Mn (Manganese) | — | 1.5 |
| Si (Silicon) | — | 1 |
Mechanical Properties
| Property | Value | Condition |
|---|---|---|
| Tensile Strength | ≥ 520 MPa (75 ksi) | — |
| Yield Strength (0.2%) | ≥ 205 MPa (30 ksi) | — |
| Elongation | ≥ 30% | — |
| Hardness | ≤ 90 HRB | annealed |
| Density | 7.94 g/cm³ | — |
Physical Properties
| Property | Value |
|---|---|
| Melting Range | 1357 – 1385 °C |
| Max Service Temp — 800H | 815°C (creep-limited) |
| Max Service Temp — 800HT | 980°C |
Corrosion Resistance
Excellent oxidation and carburization resistance up to 980°C. Good resistance to sulfidation and nitriding atmospheres. Superior stress rupture strength compared to 304H/321H at temperatures above 650°C. Resistant to sigma phase embrittlement during long-term high-temperature exposure. More resistant to chloride SCC than austenitic stainless steels.
Typical Applications
Related Standards
Available Products in This Material
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