| 摘要 |
<p>A magnetic leakage flux flaw detection method, in which by magnetizing a ferromagnetic material such as steel plate by plural magnetic fields different in intensity and detecting magnetic fluxes leaking from the ferromagnetic material after the magnetization by a magnetic sensor, or by magnetizing the ferromagnetic material by a constant intensity magnetic field and detecting the magnetic fluxes leaking from the ferromagnetic material after the magnetization by plural magnetic sensors disposed in different positions along a magnetizing direction, output signal(s) of the magnetic sensor(s) after the magnetic flux leakage detection is (are) subjected to such an arithmetic processing that a signal owing to a defect in the ferromagnetic material is emphasized. Further, with this magnetic leakage flux flaw detection method, since the defect can be detected with high accuracy, if, by this method, a defect detection is performed for a hot rolled steel plate after hot rolling, and a position where the detected defect exists is specified, it is possible to manufacture the hot rolled steel plate having a scale or subjected to a descaling treatment, in which accurate position information of the defect is previously known.</p> |
