METHOD OF EDDY CURRENT CONTROL Russian patent published in 2018 - IPC G01N27/90 

FIELD: fault detection.

SUBSTANCE: invention relates to the field of nondestructive testing and can be used for eddy current control of electrically conductive objects. Install applied eddy current transducer, connected to an electronic unit with the possibility of amplitude-phase processing of the signal. Compensate the eddy current signal of the converter on the defect-free part of the monitored object. Adjust the phase of the reference voltage for the amplitude-phase transformation of the eddy current signal. Install eddy current transducer in the measuring zone symmetrically above the measured crack. Record variation of the eddy current signal with respect to the compensated eddy current signal after the amplitude-phase transformation. Use the registered change to determine the depth of the measured crack in the controlled area according to the calibration characteristics obtained with control samples with artificial cracks of different depths. Preliminary choose eddy current transducer with an equivalent radius R_e, not exceeding the distance B₁₂ from the measured crack to the neighboring crack oriented along it. Before adjusting the phase of the reference voltage, it is placed in front of the measuring zone with the external side of the adjacent crack not facing the measured crack at a distance R_H=B₁₂-R_e, where B₁₂ – the distance between the measured and adjacent cracks in the measurement zone, and the phase of the reference voltage is controlled from the condition of suppression of the eddy current signal introduced by the neighboring crack.

EFFECT: increased reliability of a defectometric estimate of the depth of a crack by suppressing the effect of an adjacent crack oriented along the measured one.

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