NiCr-NiSi (Type K) thermocouple finds the widest use in all basemetal thermocouple, at temperature above 500 °C.The main chemical composition of positive leg NiCr (KP) are Ni≈90% and Cr≈10%; negative leg NiSi (KN) are Ni≈97% and Cr≈3%. The operating temperature range is -200~1300°C(for short term) and 0~1100°C( for long term) .
Type K thermocouple has strong resistance to oxidation than other base metal thermocouples. It has high EMF against Platinum 67, excellent temperature accuracy, sensitivity and stability, with a low cost. It is recommended for oxidizing or inert atmospheres, but cannot be used directly in the following case:
(1) Alternatively oxidizing and reducing atmosphere,
(2) Atmosphere with sulphur gases,
(3) Long time in vacuum,
(4) Low oxidizing atmosphere such as hydrogen and carbon monoxide atmosphere.
Type K Temperature Range:
(1)Thermocouple grade wire, -200~1300℃(for short term) and 0~1100℃( for long term)