Alloys
FeCrAl alloys
Ferritic iron-chromium-aluminium alloys with scaling resistance up to 1425°C
Chemical composition
FeCrAl alloys are ferritic stainless steels containing aluminium. The high aluminium content combined with high chromium causes the scaling temperature to rise to 1425°C (2600°F). FeCrAl alloys demonstrate superior heat resistance to most other commercial Fe and Ni base alloys in the majority of gas environments.
| Trade mark | % Cr | % Al | Other additions | Scaling temp (°C / °F) |
|---|---|---|---|---|
| Kanthal APM | 22 | 5.8 | — | 1425 / 2600 |
| Kanthal APMT | 21 | 5.0 | Mo 3.0% | 1425 / 2600 |
| Kanthal A-1 | 22 | 5.8 | — | 1400 / 2550 |
| Kanthal AF | 22 | 5.3 | Y | 1300 / 2370 |
| Kanthal D | 22 | 4.8 | — | 1300 / 2372 |
| Alkrothal | 15 | 4.3 | — | 1100 / 2010 |
Physical and mechanical properties
| Property | Kanthal AF | Kanthal A-1 | Kanthal APM | Kanthal APMT | Kanthal D |
|---|---|---|---|---|---|
| Scaling temperature (°C / °F) | 1300 / 2372 | 1400 / 2552 | 1425 / 2597 | 1425 / 2597 | 1300 / 2372 |
| Max continuous operating temp (°C / °F) | 1300 / 2372 | 1400 / 2552 | 1250 / 2282 | 1250 / 2282 | 1300 / 2372 |
| Density (g/cm³) | 7.15 | 7.10 | 7.10 | 7.25 | 7.25 |
| Electrical resistivity (Ω mm²/m) | 1.39 | 1.45 | 1.45 | 1.40 | 1.35 |
| Tensile strength (MPa) | 650 | 670 | 670 | 742 | 630 |
| Yield point (MPa) | 470 | 460 | 450 | 540 | 470 |
| Hardness (Hv) | 230 | 225 | 225 | 250 | 220 |
| Elongation (%) | 20 | 22 | 27 | 26 | 21 |
| Melting point (°C / °F) | 1500 / 2732 | 1500 / 2732 | 1500 / 2732 | 1500 / 2732 | 1500 / 2732 |
| Emissivity (fully oxidized) | 0.70 | 0.70 | 0.70 | 0.70 | 0.70 |
| Magnetic up to approx. | 600°C | 600°C | 600°C | 600°C | 600°C |
Creep strength — 1% elongation in 1000 h (MPa)
Kanthal APMT, manufactured by powder metallurgy, shows significantly higher creep strength than other FeCrAl grades at elevated temperatures — an important advantage for tube and element applications operating under sustained mechanical load.
KANTHAL is a trademark of Kanthal AB.