In-situ dynamic monitoring of phase transformation in steels using a multi-frequency electromagnetic sensor

An industrial-scale electromagnetic (EM) sensor is employed to non-destructively and dynamically monitor the microstructural phase transformation for mild steel samples with different thicknesses (3 mm, 6 mm, and 10 mm), high carbon steel (0.76 wt% C) and 2.25Cr-1Mo steel plates. The continuous cooling process of these samples in ambient air (cooling rate of 0.99-7.53 degrees C/s) on a run-out table is examined. To determine the phase fractions based on the EM sensor signal and measured temperature, a finite element (FE) model for the EM sensor is utilised. The obtained phase fractions are further validated by conducting dilatometry measurements inde-pendently, confirming the accuracy of the transformation behaviour and phase fraction determination derived from the EM sensor readings.