We prepared a magnetic single-yoke probe combined with a hall sensor, and measured hysteresis loops of specimens and detected distributions of leakage magnetic flux using the perepared probe to investigate a potential of simultaneous NDE for material characterization and micro defect. The undeformed and deformed low carbon steels with/without a hole were manufactured as specimens; the deformation modelled the degradation in material and the hole imitated a micro defect. The hysteresis loop was sensitive to deterioration in material, while was insensitive to a hole: the loops inclined toward the horizontal axis and the coercive force increases, with increasing degradation. Though the scanning flux distribution was effective for the detection of a hole, it shows no variation for the material degradation: the profile shows rapid change around the hole. Thus, deterioration and micro defect can be evaluated separately by a single measurement configuration, which indicates material deterioration and detecting micro defect are evaluated simultaneously. In this study, AC current was used for the excitation of materials: this contributes to simultaneous measurement, and also has a potential to enhance the reliability of measurement in micro defects.
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