Process allowing background noise to be reduced during eddy-current testing of metal tubes, and tubes produced using this process
US5634365A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 26, 1994 |
| Grant date | Jun 3, 1997 |
| Priority date | — |
| Expiry date | Jul 26, 2014 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB21B2015/0078
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The process relates to the aptitude for detectability of defects using eddy-currents on metal tubes cold laminated using a pilger mill and relates more particularly to the possibility of reducing the background noise and increasing the ratio between a standard signal and this background noise. The process consists of carrying out, after reduction in section by at least 30% in a cold pilger mill, a hollow drawing pass with a reduction in the external diameter of approximately 0.1% to 5%. The signal/background noise ratio can in this way be multiplied by a factor of between 2 and 3.7, in the case of a series of tubes made of INCO 690 alloy, as shown in the single figure. The invention also relates to tubes produced using this process. Application in production of steam generating tubes for nuclear power stations.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.