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Grades and composition
Two alloy families: nickel-chromium for high temperature, copper-nickel for lower temperature and precise resistance.
Nickel-chromium
| Grade | Nominal composition | Max service | Atmosphere | Wound into |
|---|
| NiCr 80/20 | Ni 80 / Cr 20 | 1,200 °C | Oxidising, no sulphur | Furnace and kiln elements |
| NiCr 60/15 | Ni 60 / Cr 15 / Fe balance | 1,150 °C | Oxidising, no sulphur | Elements with shorter duty cycles |
Both are austenitic and form a protective chromium oxide layer in service. That layer is what gives the service life; in a reducing or sulphur-bearing atmosphere it does not form, and the element fails early. Tell us the atmosphere — it decides the grade as much as the temperature does.
Copper-nickel
| Grade | Nominal composition | Relative resistivity | Used for |
|---|
| CuNi 1 | Cu / Ni 1 | Lower resistance | Wiring, low-value resistors |
| CuNi 10 | Cu / Ni 10 | Low | Resistors, heating cable |
| CuNi 23 | Cu / Ni 23 | Medium | Resistors, shunts |
| CuNi 44 | Cu / Ni 44 | Highest of the family | Precision resistors, thermocouple negative leg |
| CuMn12Ni | Cu / Mn 12 / Ni | Low, temperature-stable | Precision and standard resistors |
What the certificate states per grade
| Resistivity | Measured, per lot, in ohm·mm²/m |
| Diameter | Measured in-line, 0.001 mm resolution |
| Tensile and elongation | Per lot, so the windability is known before winding |
| Composition | Melt analysis, on 3.1 certificates |
Enamelled variant
| Grades | CuNi1 to CuNi44, CuMn12Ni |
| Enamel | Polyurethane (UEW) |
| Diameter | 0.05 – 1.0 mm |
| Standards | IEC 60317; GB/T 6109 |
| Tested | Breakdown voltage, adhesion, elongation, solderability |
