These alloys are especially characterised by high resistivity and high resistance to oxidation and chemical corrosion. Electrical resistance alloys are mostly found in the electrical and electronics industry. They are widely used whenever electrical energy is converted into heat, as in ceramic cook tops, electrical heaters, toasters or coffee machines. There are two main types of alloys in this category, Nickel-Iron-Chromium Alloys and FeCrAl Alloys. Nickel-Iron-Chromium alloys are commonly used in production of resistance wire because of their high resistivity and stable oxidation resistance properties at temperatures up to 1250°C. Because of that resistance wires are well-suited for extreme environments. FeCrAl alloys are ferritic alloys whose electrical resistance properties are similar to those of the Nickel-Iron-Chromium alloys, making them suitable for electrical heating applications, but absence of Nickel makes them cheaper than Nickel-Iron-Chromium alloys, it also makes them more prone to corrosion.
Nickel-Chromium Products
- NiCr 80 20 (UNS N06003 / Werkstoff Nr 2.4869) – suitable for operating at temperatures upto 1200°C.
- NiCr 70 30 (UNS N06008 / Werkstoff Nr 2.4658) – suitable for operating at temperatures upto 1250°C.
- NiCr 60 15 (UNS N06004 / Werkstoff Nr 2.4867) – suitable for operating at temperatures upto 1150°C.
- NiCr 40 20 (UNS – / – ) – suitable for operating at temperatures upto 1100°C.
- NiCr 30 20 (UNS – / Werkstoff Nr 1.4860) – suitable for operating at temperatures upto 1080°C.
Iron-Chromium-Aluminum Products
- FeCrAl 135 (UNS – / Werkstoff Nr 1.4767) – suitable for operating at temperatures upto 1250°C.
- FeCrAl 125 (UNS K91670 / Werkstoff Nr 1.4725) – suitable for operating at temperatures upto 1150°C.
Product forms
| Product | Size (mm) | Condition of Supply |
| Wire | 0.10 – 12.0 | Bright Annealed Oxidized |
| Bar | 5.0 – 60.0 | Hot Finished Cold Finished Peeled Bright Turned Bright Annealed |
| Strip | Thickness 0.20 – 5.0 Width 10 – 100 |
Cold Finished Bright Annealed |
| Ribbon | Thickness 0.2 – 1.0 Width 2.0 – 4.5 |
Bright Annealed Flat Rolled |
| Stranded Wire | 2.5 – 3.0 | Hard Annealed |
Chemical Composition
| Alloy | Ni (%) | Mn (%) | Fe (%) | Si (%) | Cr (%) | C (%) | Cu (%) | Al (%) |
| NiCr 80 20 | 77.0-80.0 | 1.0 | 1.0 | 0.5-1.5 | 19.0-21.0 | 0.1 | 0.5 | 0.3 |
| NiCr 70 30 | 67.0-70.0 | 1.0 | 1.0 | 1.0-2.5 | 28.0-32.0 | 0.1 | 0.5 | 0.2 |
| NiCr 60 15 | 57.0-60.0 | 1.0 | Bal. | 1.0-1.7 | 14.0-17.0 | 0.1 | 0.5 | 0.3 |
| NiCr 40 20 | 37.0-40.0 | 1.0 | Bal. | 1.8-3.0 | 18.0-22.0 | 0.1 | 0.5 | 0.3 |
| NiCr 30 20 | 28.0-30.0 | 1.0 | Bal. | 1.8-3.0 | 18.0-22.0 | 0.1 | 0.5 | 0.3 |
Physical properties
| Alloy | Specific Resistant (Electrical Resistivity) (µΩ-mm) |
Density (g/cm3) | Coeff. of Linear Expansion between 20 – 1000°C (10-6/K) |
Maximum Operating Temperature (°C)(in Air) |
| NiCr 80 20 | 1.09 | 8.4 | 17 | 1200 |
| NiCr 70 30 | 1.18 | 8.2 | 17 | 1250 |
| NiCr 60 15 | 1.12 | 8.2 | 17 | 1150 |
| NiCr 40 20 | 1.04 | 7.9 | 18 | 1100 |
| NiCr 30 20 | 1.04 | 7.9 | 18 | 1080 |
Mechanical properties
| Alloy | Tensile Strength Min – Max (MPa) |
Elongation, % (L0=100mm) |
| NiCr 80 20 | 700-900 | 28-35 |
| NiCr 70 30 | 750-950 | 28-35 |
| NiCr 60 15 | 700-850 | 28-35 |
| NiCr 40 20 | 700-850 | 28-35 |
| NiCr 30 20 | 700-800 | 28-35 |