Kontaktlose Temperaturmessung während der sekundärmetallurgischen Behandlung

Temperature measurement plays an important role in steel production, enabling good temperature management and thus high process stability. Two methods are available for temperature measurement: one method uses a temperature measuring lance that is immersed in the melt, and the second method measures the steel temperature optically and thus without contact. The calibration of contactless temperature measurement, taking into account the radiation properties of the molten steel, plays a decisive role here. This work investigates, two chemically different steel grades in the course of three measurement campaigns. During the experiment, the steel temperature was measured at the same time using a temperature measuring lance on the one hand and an infrared thermal camera on the other, and the two measurements were correlated. In addition, the variable parameters of the infrared thermal camera were analyzed in a parameter study in order to gain precise knowledge of how the camera system works. The aim was to calibrate the infrared thermal camera by means of correlation and the parameter study so that it could measure the steel temperature optically. The results show that the emissivity of the steel melt is the main influencing factor for reliable optical temperature measurement. This emissivity, in turn, depends on the chemical composition of the two steel grades, with the carbon content in the melt being identified as the primary factor affecting emissivity.