Method and apparatus for evaluating length of defect in eddy current testing
US8339130B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 16, 2011 |
| Grant date | Dec 25, 2012 |
| Priority date | — |
| Expiry date | Feb 16, 2031 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N27/9046
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The surface length of a metal subject to be inspected is evaluated by detecting an eddy current without using a combination of a scale and visual or liquid penetrant inspection. An exciting coil and a detecting coil are scanned above the subject in a length direction. An eddy current detector measures an output voltage corresponding to scanning positions based on an output from the detecting coil. Based on an output voltage distribution curve indicating a distribution of output voltages corresponding to the scanning positions, position information is extracted corresponding to values which are within a differential voltage range and lower by 12 dB than a maximum value of the output voltages on the left and right sides of the distribution. A distance between the positions included in the extracted information is calculated to evaluate the length of a slit which is a defect present on the subject surface.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.