Research On Technique of Dual-Frequency Eddy-Current Inspection for Continuously Casting Hot Slab

Two-dimension eddy current inspection model is taken for researching the effect of the eddy current transducer structure parameter upon the inspection sensitivity. Dual-frequency eddy current inspection is applied to the inspection of slab surface defects. The results of experiment prove that the change of sensor impedance due to the change of crack depth causes the phase angle of impedance to change.