FeCrAl, NiCr, pure nickel and precision resistance alloys with typical resistivity, maximum service temperature and available forms.
| Grade | Family | Resistivity (μΩ·m, 20 °C) | Max service temp. (air, approx.) | Forms supplied | Notes |
|---|---|---|---|---|---|
| 0Cr25Al5 | FeCrAl | 1.40 | 1250 | Wire, strip, ribbon | General-purpose FeCrAl; best balance of cost and life |
| 0Cr21Al6Nb | Nb-bearing FeCrAl | 1.45 | 1350 | Wire, strip, formed elements | Niobium addition resists sagging; preferred for long high-temperature runs |
| 0Cr27Al7Mo2 | FeCrAl | 1.53 | 1400 | Wire, strip | Highest temperature capability in the FeCrAl family |
| 1Cr13Al4 | FeCrAl | 1.25 | 1000 | Wire, strip | Cost-effective for low and medium temperature furnaces |
| 0Cr23Al5 | FeCrAl | 1.10 | 1150 | Strip, ribbon | Common strip grade for furnace elements |
| Cr20Ni80 | NiCr | 1.09 | 1200 | Wire, strip, ribbon | Best ductility and thermal fatigue resistance |
| Cr15Ni60 | NiCr | 1.12 | 1150 | Wire, strip | Economical NiCr with good formability |
| Cr30Ni70 | NiCr | 1.18 | 1250 | Wire, rod | Higher chromium for oxidation resistance |
| Ni200 / N6 | Pure nickel | 0.096 | 600 | Wire, strip, foil | Conductivity and corrosion resistance; not a heating element |
| Constantan 6J40 | CuNi | 0.49 | -- | Wire, strip, foil | Precision resistance alloy for shunts and sensing |
| Manganin 6J12/6J13 | CuMnNi | 0.43-0.47 | -- | Wire, strip, foil | Low temperature coefficient; precision resistors |
Typical values at 20 °C; final selection must be verified against actual working conditions. Maximum service temperature in air is approximate and depends on atmosphere, support and surface load.
| Atmosphere | Recommended | Reason |
|---|---|---|
| Clean air / oxidising | FeCrAl or NiCr | Standard selection applies |
| Sulphur-bearing | FeCrAl only | Sulphur destroys the Cr₂O₃ film and forms low-melting nickel sulphides |
| Carburising | NiCr preferred | FeCrAl oxide film may reduce and form carbides |
| Vacuum / dry hydrogen | NiCr preferred | FeCrAl loses aluminium by volatilisation |
FeCrAl grades reach higher temperatures (0Cr25Al5 approx. 1250 °C, 0Cr21Al6Nb approx. 1350 °C), have higher resistivity and contain no nickel, so cost is more stable. NiCr grades (Cr20Ni80) offer better room-temperature ductility and thermal fatigue resistance, which suits frequent cycling and repeated dismantling. In sulphur-bearing atmospheres, avoid NiCr; in carburising or vacuum service, NiCr is generally safer.
Not by name only. Resistivity differs between grades (0Cr25Al5 approx. 1.40 vs Cr20Ni80 approx. 1.09 μΩ·m), so the same dimensions give a different power. Recalculate cross-section and developed length, then re-check surface load.
Yes. Wire from φ 0.03 mm, strip from 0.05 mm thickness and 2 mm width, including slit, corrugated and edge-folded forms. Prototypes can be supplied for verification before batch orders.
