| 摘要 |
PURPOSE:To detect the structure irregularity of the surface part of an object body quantitatively by moving the object body and probes relatively and detecting variation of an eddy current generated at the surface part of the object body. CONSTITUTION:The probes 4 and 4' have inversely V-shaped coils 10; two coils 10 which differ in spread distance are arranged, spread sides of the coils 10 are arranged opposite a roll 7 which is suppored rotatably, and their tips are put closer to the surface of the roll 7, which while rotated is moved lengthwise to body length to scan the entire surface of the roll. An exciting current of 256KHz high frequency is applied from an eddy current flaw detecting device body 1 to one probe 4 and an exciting current of 65KHz low frequency is applied to the other probe 4 to generate an eddy current at the surface part of the rotating roll 7; and the probes 4 and 4' are moved in the lengthwise direction of the roll 7 to scan the entire surface of the roll 7. |
