Constantan Wire for Thermocouple, Extension and Compensating Wires.
Material can be ordered to all National or International emf standards as well as customer’s own specifications. Scott Precision Wire Constantan alloys are available in solid wire, strip or tape and flexible bunch or strand constructions.
The alloy composition is carefully controlled to provide a range of emf outputs to suit the following thermocouple combinations:
| Thermocouple Type | Constantan Alloy | RangeTemp. | Constantan Description |
|---|---|---|---|
| J | ConJ | 0 - 750°C | To form the negative leg of the thermocouple or extension wire combination. Matched to Thermocouple Iron |
| ConJX | 0 - 200°C | ||
| T | ConT | 0 - 350°C | To form the negative leg of the thermocouple or extension wire combination. Matched to Thermocouple Copper |
| ConTX | 0 - 100°C | ||
| E | ConE | 0 - 900°C | To form the negative leg of the thermocouple or extension wire combination. Matched to Nicro |
| ConEX | 0 - 200°C | ||
| K (KC) Compensating | ConKCA | 0 - 150°C | To form the negative leg of the compensating wire combination. Matched to Thermocouple Copper |
| ConKCB | 0 - 100°C | ||
Physical and Mechanical Properties of Constantan Wire
| | Units | Constantan |
|---|---|---|
| Nominal composition | % | Cu 56 |
| Ni 44 | ||
| Density at 20°C | g/cm³ | 8.9 |
| Resistivity at 20°C | µΩcm | 49 |
| Temperature Coefficient of Resistance | 1/K | 0.00004 |
| Coefficient of thermal expansion 20 – 100°C | 1/K | 13.5 x 10^6 |
| Thermal conductivity at 20°C | W/mK | 23 |
| Specific Heat Capacity at 20°C | kJ/kgK | 0.41 |
| Melting point (approx.) | °C | 1280 |
| Magnetic properties | Non-Magnetic | |
| Tensile strength Rm(0.5mm annealed wire) | N/mm² | 420 |
The figures given in these tables represent nominal or typical values.
Information contained within this technical data sheet is based upon the general experience of Scott Precision Wire Ltd and is believed to be correct at the time of issue.
No warranty is given or is to be implied from the details above.
Customers are advised to carry out independent tests in order to determine the suitability of any Scott Precision Wire Ltd product for an application.
constantan wire faq's
Constantan is a non-magnetic electrical resistance alloy composed of copper and nickel, known for its nearly constant electrical resistance across a wide range of temperatures.
The resistivity of constantan at 20°C is nominally 49µΩcm. For comparison, this is below Cromaloy A (135µΩcm) but higher than Kutherm 3 and 10 (3 and 10.2µΩcm respectively).
The melting point of constantan is approximately 1280°C.