Multichannel Array Magnetic Flux Leakage Testing System Using Hall Devices

By using Hall devices with high sensitivity, multi-channel array magnetic flux leakage sensor and its signal processing circuit were designed and developed. The experiments of testing defects in ferromagnetic samples with different parameters and sizes were carried out. The developed magnetic flux leakage detection system realized the image display of defect signals under geomagnetic excitation and artificial weak magnetic excitation. The display method of subject defects based on signals from testing system was discussed. In addition, the nonlinear inversion between flaw parameters and tested signals could be mapped by using the technique of artificial neural network, that could be used to quantitatively analyze the subject flaw.