What are the index numbers of thermocouples?

What are the index numbers of thermocouples? What are the characteristics? Thermocouple index number is mainly S, R, B, N, K, E, J, T and other types. Among them, S, R, and B belong to noble metal thermocouples, and N, K, E, J, and T belong to inexpensive metal thermocouples. The S index No. is characterized by strong anti-oxidation performance, and it should be used continuously in oxidizing and inert atmospheres. The long-term use temperature is 1400°C and short-term 1600°C. Among all the thermocouples, the S index number has the highest accuracy level and is usually used as a standard thermocouple; the R index number is about 15% larger than the S index number, and the other performances are almost identical;}B The indexing number is extremely small at room temperature, so there is no need to use compensation wires for measurement. Its long-term use temperature is 1600 °C, short-term 1800 °C. It can be used in an oxidizing or neutral atmosphere, but it can also be used under vacuum conditions for a short period of time. The N index number is characterized by high temperature oxidation resistance at 1300°C, long-term stability of the thermo-electromotive force and good reproducibility of the short-term thermal cycle, good resistance to nuclear irradiation and low temperature resistance, and can partially replace the S index number Thermocouple; K indexing number is characterized by strong anti-oxidation, it should be used continuously in oxidizing, inert atmosphere, long-term use temperature 1000 °C, short-term 1200 °C. It is the most widely used of all thermocouples; the E-index number is characterized by the largest thermo-electromotive force among the commonly used thermocouples, that is, the highest sensitivity. Suitable for continuous use in oxidizing, inert atmosphere, using temperature 0-800°C; J indexing number is characterized in that it can be used in oxidizing atmosphere (Upper temperature limit 750°C), but also in reducing atmosphere (Upper temperature limit 950 °C), and resistance to H2 and CO gas corrosion, mostly used in oil refining and chemical industry; T index number is characterized by the highest level of accuracy in all cheap metal thermocouples, usually used to measure temperatures below 300 °C.