High Temperature Thermocouples Using Tungsten - Rhenium Alloy Tubing 620417
Development of coaxial type high temperature thermocouples was initiated by manufacturing tungsten-26% rhenium alloy seamless tubing, which has excellent room temperature bend ductility in addition to inherent advantages of high strength and very high melting point. Tungsten/tungsten-28% rhenium coaxial thermocouples were directly fabricated from large billets. Tungsten-rhenium alloy tubes were reduced by hot fabrication to coaxial thermocouple wire.
Coaxial tungsten/tungsten-26% rhenium thermocouples were calibrated in hydrogen atmosphere. The thermal emf of coaxial units above 2700 F was lower than the calibration for conventional, wire type thermocouples, but the departure might be attributed to variations in alloy composition or calibration techniques.