Inductive Sensor for Magnetic Property Evaluation in Hot Rolling Mill Wire Production

This paper presents the results of a preliminary investigation for the development of an inductive sensor system for in-situ measurements in hot rolling mill steel wire production. The developed system should monitor the surface layer of the wire concerning changes in the microstructural composition using magnetic property evaluation. The sensor consists of two surrounding coils and evaluates a measure related to the slope of the commutation curve around the origin of the coordinate system This presented preliminary investigation discussed, whether the evaluation of the AC commutation curve under nonnegligible eddy currents is suitable to distinguish between two different microstructures. In addition, it was investigated, whether the measurement concept remains valid under plant conditions with high temperatures up to 600 degrees C. Within this work, two samples of 17 mm diameter and 175 mm length with different microstructural compositions could be distinguished under laboratory conditions at room temperature and in high-temperature experiments. The results could be plausibilized using the virgin magnetization curve in COMSOL Multiphysics, which was modified to model the magnetic behavior of the material for higher temperatures.