Studies on the tungsten-rhenium thermocouple to 2000 °C.

Abstract

Various lots of tungsten and rhenium wire were obtained from leading American manufacturers. Eleven tungsten-rhenium thermocouples were made up from these wire samples and tested at approximately 100 degrees °C intervals up to 2000 °C. A fourth order equation and a third order equation were selected to represent the emf of the tungsten-rhenium thermocouple in the range from 0 to 1000 °C and from 1000 to 2000 °C respectively. Using these two equations, reference tables were established and are presented in 5 degrees °C intervals from 0 to 2000 °C and in 10 degrees °F intervals from 32 to 3640 °F. Inverse tables giving temperature in °C and °F at 20 microvolt intervals arc also included. Information is furnished on variations due to wire size and among different wire lots and different wire manufacturers. Spectrochemical analyses of the tungsten and rhenium elements that were used to represent the tables of temperature versus emf are listed. A graphic comparison is made between the NBS emf values and values from other investigators.