Thermocouple wire

One hundred years ago, hardly anyone could have imagined such a rapid development of non-ferrous metallurgy. As Mark Twain once remarked. it is difficult to prophesy, especially with regard to the future.

The qualities of thermocouple wire

Thermocouple wire is made from such alloys as alumel, chromel of TM and T grades, copel, and constantan. Their physical qualities are directly dependent on the ratio of components. Alumel is very ductile, able to retain strength for a long time. Constantan paired with iron, copper and chromel is characterized by high electrical resistance, independent of temperature. Kopel paired with copper, iron and chromel, has similar properties to contantan: large thermoelectromotive force, minimum temperature coefficient of electrical resistance, high heat resistance up to 600 °C and resistance to corrosion. Chromel is characterized by high heat resistance and variation of thermal EMF in a wide range.

Advantages of thermocouple alloys:

  • heat resistance;
  • high specific electrical resistance;
  • average temperature coefficient of linear expansion;
  • low density;
  • significant thermoelectromotive force.

The most important property of thermocouple wire is considered to be a high stable thermal EMF within the operating temperature range.

Application of

Manufacturing of measuring and transducer devices, compensation wires, automation systems operating at high temperatures. A thermocouple consists of two different conductors, one end of which is soldered together and placed in a medium to measure temperature (the so-called "hot contact") and the two free ends are lowered into a thermostat - the "cold contact".

How a thermocouple works

The thermoelectric effect lies in the potential difference that arises between conductors of different materials when the temperature rises. Thermocouples are designed to measure very high temperatures. For accurate readings at relatively low temperatures, thermocouples with a high thermoelectric EMF are used. Their positive electrodes are iron, chromel or copper and their negative electrodes are alumel, constantan or copel. By the value of thermo-EMF the leading thermocouple is chromel-copel (TCK), used at t° up to 800 ° C, followed by copper-copel and iron-copel (up to 760 ° C)... Compensation wires - transfer potential from the free ends of the thermocouple to the sensor. Cheaper thermocouple wires are used for such wires: chromel of K and KM grades, as well as copel, constantan. The last two grades are used for making resistance standards.

Varieties of thermocouple wire

  • alumel-chromel (TXA), measurement range 200 - 1000 °C;
  • copel - chromel (ТХК), temperature range 200 - 800 °C;
  • constantan - chromel (TXC), measures t° from -40 to 880 °C;
  • Iron-constantan, measures cryogenic temperatures;
  • Copper-constantan, measures t° from 250 to 300 °C;
  • Iron-copper, measures t° from 0 to 750 °C;
  • Tungsten-rhenium, used to measure the highest temperatures up to 3000 °C in an inert environment.


We supply certified thermocouple wire. The technical documentation includes data on the chemical composition, the limiting percentage of impurities; mechanical properties of the products. From us you can buy in bulk any semi-finished products for large-scale productions. We also offer optimum conditions for retail buyers. The high level of service and responsiveness of service is the face of our company.

Buy at the best price

High quality thermocouple wire is always in stock of Evek GmbH at an optimal price. It is formed taking into account the European rates for non-ferrous metals without including additional costs. The quality certificate for the products includes data on chemical composition, maximum percentage of impurities; mechanical properties. Cooperation with us provides a number of advantages. Our specialists will be happy to provide advice on purchasing any alloys, the correct choice of which will depend on the performance and durability of the equipment. We will help to determine not only the optimum parameters of the product, but also offer the best price.