A non-contact sensor capable of measuring aluminium surface temperature during hot rolling, extrusion, cold rolling and annealing, for all alloys, surface-textures and -conditions, with an accuracy better than 1% has been developed. The developed sensor is based on the principle of Auxiliary Reference Thermometry(ART), employing two reference radiators and two pyrometers.
The sensor has been tested successfully for moving strip at temperatures between 350-475K, with an accuracy of 2K. Preliminary tests indicate that an extension of the measurement range up to 750K will be possible.
The sensor functions independent of material composition, or microstructure and therefore may be applied at numerous positions of the aluminium rolling or extrusion process and can be used for all alloy systems with minimal recalibration. This is a distinct benefit over current pyrometry based detection systems that are available. The sensor, with a size of 200x400mm has to be positioned at a distance of 20mm above the strip; for emergencies and to protect the sensor from the head and tail of the strip during hot rolling a retraction device has to be incorporated in the positioning system.
Outside of the aluminium industry the sensor can be used on other reflective surfaces to contact less measure temperature in the range 350 - 750K.