Process for detecting defects on a surface by eddy currents and device for carrying out said process
US4799010A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 20, 1986 |
| Grant date | Jan 17, 1989 |
| Priority date | — |
| Expiry date | May 20, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N27/904
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A magnetic field is produced by way of an emitter placed close to the surface of a product to be controlled and a receiver separate from the emitter is placed, with respect to said emitter, on the one hand, in such a way as to be aligned with the emitter in a direction corresponding to the general orientation of the defects to be detected on the surface of the product, and on the other hand, so as to avoid any substantial direct influence from the eddy currents generated by the emitter when the product surface is defect-free, so that a significant signal is only picked up by the receiver in the case of a deviation of said eddy currents in its direction due to a discontinuity in the surface of the product. The invention finds an application in the detection of surface defects in semi-finished metallurgical products and in particular continuously cast steel products.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.