Constantan Wire with moderate resistivity and low temperature coefficent of resistance with a flat resistance/temperature curve over a wider range than the “manganins”. Constantan also shows better corrosion resistance than the man ganins. Uses tend to be restricted to ac circuits.
Constantan wire is also the negative element of the type J thermocouple with Iron being the positive; type J thermocouples are used in heat treating applications. Also, it is the negative element of the type T thermocouple with OFHC Copper the positive; type T thermocouples are used at cryogenic temperatures.
The alloy is non-magnetic. It is used for electrical regenerator’s variable resistor and the strain resistor,
potentiometers, heating wires, heating cables and mats. Ribbons are used for heating of bimetals. Another field of application is manufacturing of thermocouples because it develops a high electromotive force (EMF) in association with others metals.
Copper nickel alloy series:Constantan CuNi40 (6J40), CuNi1, CuNi2, CuNi6, CuNi8, CuNi10, CuNi14, CuNi19, CuNi23,CuNi30, CuNi34, CuNi44.
Size dimension range:
Wire: 0.1-10mm
Ribbons: 0.05*0.2-2.0*6.0mm
Strip: 0.05*5.0-5.0*250mm
Main grades and properties
Type | Electrical resistivity (20degreeΩ mm²/m) |
temperature coefficient of resistance (10^6/degree) |
Dens ity g/mm² |
Max. temperature (°c) |
Melting point (°c) |
CuNi1 | 0.03 | <1000 | 8.9 | / | 1085 |
CuNi2 | 0.05 | <1200 | 8.9 | 200 | 1090 |
CuNi6 | 0.10 | <600 | 8.9 | 220 | 1095 |
CuNi8 | 0.12 | <570 | 8.9 | 250 | 1097 |
CuNi10 | 0.15 | <500 | 8.9 | 250 | 1100 |
CuNi14 | 0.20 | <380 | 8.9 | 300 | 1115 |
CuNi19 | 0.25 | <250 | 8.9 | 300 | 1135 |
CuNi23 | 0.30 | <160 | 8.9 | 300 | 1150 |
CuNi30 | 0.35 | <100 | 8.9 | 350 | 1170 |
CuNi34 | 0.40 | -0 | 8.9 | 350 | 1180 |
CuNi40 | 0.48 | ±40 | 8.9 | 400 | 1280 |
CuNi44 | 0.49 | <-6 | 8.9 | 400 | 1280 |