| 摘要 |
<p>[Object] In a magnetic flux leakage inspection method, a method for magnetic flux leakage inspection for measurement and analysis that can accurately capture a true signal due to a defect with a measurement result unaffected by a change of a measurement condition. [Means of Realizing the Object] A magnetic flux leakage inspection method generates a magnetic flux parallel to a surface of an inspected object, and detects a magnetic flux that leaks from the surface of the inspected object with a magnetic sensor. The magnetic flux leakage inspection method includes exciting coils that generate an alternating magnetic field having a variable frequency, an exciting coil power source, the magnetic sensor that detects a component horizontal to a magnetic field leaked from the surface of the inspected object, a lock-in detector that detects signals having the same frequency as the exciting coils from an output from the measuring circuit of the magnetic sensor, and a signal analyzer that analyzes changes of a signal intensity and a phase of the output of the magnetic sensor with output signals of the lock-in detector. The magnetic flux leakage inspection method obtains cosine or sine as a trigonometric function of a phase obtained by adding to the phase at each measurement point of multipoint measurement, an adjustment phase common to all the measurement points, and displays an analytical value obtained by multiplying the signal intensity and the sine or the cosine at each measurement point with any adjustment phase.</p> |
