Type K Thermocouple (Chromel / Alumel) is the most common type of thermocouple. It’s inexpensive, accurate, reliable, and has a wide temperature range. The type K is commonly found in nuclear applications because of its relative radiation hardness. Maximum continuous temperature is around 2012°F (1,100°C).
Type K Chromel (+) vs. Alumel (-) is generally used to measure high temperature to 2300°F (1260°C). It should not be used for accurate temperature measurements below 900°F (482°C) or after prolonged exposure above 1400°F (760°C). If unprotected (bare wire) it should only be used in inert or oxidizing atmospheres. It has a short life in alternately oxidizing and reducing atmospheres and in reducing atmospheres, particularly in the 1500 to 1850°F range.
Type K Temperature Range
- Thermocouple grade wire, –454 to 2,300°F (–270 to 1260°C)
- Extension wire, 32 to 392°F (0 to 200°C)
Type K Accuracy
- Standard: +/- 2.2°C or +/- .75%