Patent ID: 8466674

Claim:
A magnetic testing method applying a rotating magnetic field to a material to be tested and detecting a flaw based on a testing signal generated by the rotating magnetic field, the method comprising the steps of: extracting a candidate flaw signal by using an alternating current obtained by superimposing a first current and a second current having a lower frequency than the first current, as an exciting current for exciting the rotating magnetic field, synchronously detecting the testing signal by using the first current as a reference signal, and thereafter synchronously detecting by using the second current as a reference signal; displaying a testing image constructed by a plurality of pixels corresponding to respective positions of the material to be tested, each of the pixels having a gray level corresponding to an intensity of the candidate flaw signal at each of the positions, and a phase of the candidate flaw signal at each of the positions in the testing image being capable of being identified; and detecting the flaw based on the displayed testing image.