| 摘要 |
PURPOSE:To simply and efficiently perform a wide range of crack inspection within a short time with good accuracy, by detecting relatively large crack by measuring the electric resistance of a product to be inspected at the time of the supply of a magnetizing current and scattering a magnetic powder on the magnetized product to be inspected to detect a relatively small crack from the adhered state of said magnetic powder. CONSTITUTION:A product 2 to be inspected is held between magnetizing electrodes 3, 4 and a magnetizing current is flowed from a magnetizing power source 1 to detect potential difference by detectors 10, 11. The potential difference signal and the magnetizing current signal detected by a magnetizing current detecting part 5 are respectively applied to a divider circuit 16 through amplifiers 12, 14 and wave form shaping circuits 13, 15 to calculate the ratio thereof an an electric resistance signal is obtained to be compared with the reference electric signal corresponding to the size of a crack by a comparing circuit 17 and a relatively large crack is detected. Simultaneously with the completion of the supply of the magnetizing current, a magnetic powder is scattered to the product 2 to be inspected to immediately detect a small crack by a magnetic powder flaw detection method.
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