The principle on which the modern thermocouple operates is derived from Seeback’s discovery that if a circuit is formed using two dissimilar metal Conductors with one junction at a higher temperature than other, then a current will flow in the circuit. The resultant emf. is proportional to the temperature difference between the junctions .
For many industries heating processes particularly those carried out at high temperature a Thermocouple is the most accurate convenient and simple method for temperature measurement.

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Thermocouple Type & Temperature Range

TC TypeName of MaterialsApplication Range
BPlatinum 30% Rhodium (+)1200-1800°C
Platinum 6% Rhodium (-)
CW5Re Tungsten 5% Rhenium (+)1650 – 2315°C 
W26 Re Tungsten 26% Rhenium (-)
EChromel (+)0-900°C 
Constantan (-)
JIron (+)0-760°C 
Constantan (-)
KChromel (+)0-1200 °C 
Alumel (-)
NNicrosil (+)650-1260°C
Nisil (-)
RPlatinum 13% Rhodium (+)870-1650°C 
Platinum (-)
SPlatinum 10% Rhodium (+)980-1650°C
Platinum (-)
TCopper (+)-200°C – 350°C 
Copper (+)


Seamless Tube And drilled bar stock

Type Max. Temp (Recommended) Remarks
SS304 870°C Most widely used low temperature sheath material.
Extensively used in food, beverage, chemical and other industries where corrosion resistance is required.
SS316 870°C Best corrosion resistance of the austenitic stainless steel grades. Widel used in the food and chemical industry
SS310 1150°C Mechanical and corrosion resistance,similar to but better than 304 S S .Very good heat resistance
446 SS 1150°C Ferritic stainless steel which has good resistance to sulfurous atmospheres at high temperatures. corrosion resistance to nitric acid, sulfuric acid   and most alkalies.
INCONEL 600/601 1175°C  Good high temperature strength, corrosion resistance, resistance to chloride-ion stress corrosion cracking and oxidation resistance to high temperatures.
Metal Ceramic 1370°C Used in Copper, Brass and Steel industry
Silicon Carbide 1650°C Used in Aluminium Industry
Syalon® 1150°C Used in aluminium Industry
Ceramic 610 1600°C Excellent thermal mechanical and corrosion resistance.
Ceramic 710 1800°C Excellent thermal mechanical and corrosion resistance.
  *Standard thermocouple protection tube should be preheated to about 480 C before immersion in molten metal at 1100 C or higher.