A hundred years ago, hardly anyone could imagine such a rapid development of non-ferrous metallurgy. As Mark Twain once remarked, it is difficult to prophesy, especially regarding future.
Thermocouple wire quality
Thermocouple wire is made from alloys such as alumel, TM and T, chromel, kopel, constantan. Their physical qualities are directly dependent on ratio of components. Alumel — very plastic, able to maintain durability 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: high thermoelectromotive force, minimum temperature coefficient of electrical resistance, high heat resistance up to 600 °C and corrosion resistance. Chromel is characterized by high heat resistance and a wide variation in thermo-EMF.
Advantages of thermocouple alloys:
• heat resistance;
• high electrical resistivity;
• average temperature coefficient of linear expansion;
• low density;
• significant thermoelectromotive force.
The most important property of thermocouple wire is considered to be high stable indicator of thermo-EMF in range of operating temperature.
Manufacture of measuring and conversion devices, compensation wires, automation systems operating at high temperatures. Thermocouple consists of two different conductors. One end, which is soldered and placed in medium for measuring temperature (so-called «hot contact»), and two free ends are lowered into thermostat — «cold contact».
How does a thermocouple work?
Thermoelectric effect is resulting potential difference between conductors of various materials with increasing temperature. Thermocouples are designed to measure very high temperatures. For accurate readings with relatively little heat, thermocouples with high thermo-EMF are used. They have positive electrodes: iron, chromel or copper, and negative ones — alumel, constantan or kopel. Largest thermo-EMF is lead chromel-kopel (TCK) thermocouple, used at t° up to 800 °C, followed by copper-kopel and iron-kopel (up to 760 °C). Compensation wires — transfer potential from free ends of thermocouple to sensor. For such wires, cheaper thermocouple wire is used: chromel grades K and KM, as well as kopel, constantan. Last two brands are used for manufacture of resistance standards.
Varieties of thermocouple wire
- • alumel — chromel (TXA), measuring range 200 — 1000 °C;
- • kopel — chromel (THC), temperature range 200 — 800 °C;
- • constantan — chromel (TXK), measures t° from -40 to 880 °C;
- • iron-constantan, used to measure cryogenic temperatures;
- • copper-constantan, measures t° from 250 to 300 °C;
- • iron-kopel, measures t° from 0 to 750 °C;
- • tungsten-rhenium, used to determine highest temperatures up to 3000 °C in an inert atmosphere.
We supply certified thermocouple wire. Technical documentation includes data on chemical composition, maximum percentage of impurities; mechanical qualities of products. You can buy in bulk any semi-finished products for large-scale production. We also offer optimal conditions for retail customers. High level of service and prompt service are «face» of our company.
Buy at the best price
High quality thermocouple wire at best price is always available in warehouse of Elektrovek-steel company. It’s formed taking into account European rates on non-ferrous metals without including additional costs. Quality certificate for products includes data on chemical composition, maximum percentage of impurities; mechanical qualities. Cooperation with us gives a number of advantages. Our experts will be happy to provide advice on purchase of any alloys, proper functioning and durability of equipment will depend on correct choice. We will help determine not only optimal product parameters, but also offer best price.