Method and an arrangement for inspecting the surface of steel stock having a temperature above the Curie point
US4534405A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 26, 1983 |
| Grant date | Aug 13, 1985 |
| Priority date | — |
| Expiry date | Jan 26, 2003 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N27/82
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
There is disclosed a method and arrangement for inspecting the surface of steel stock having a temperature above the Curie point. In order to detect, with a great certainty and accuracy, defects in the hot steel stock, with a loss of energy for cooling the steel stock for inspection and subsequently reheating it for further processing being avoided, only a thin surface layer of the steel stock is intensively cooled on the surface to be inspected, to a temperature below the Curie point. The core of the steel remains hot. Immediately thereafter, a magnetic or electromagnetic field is induced in the cooled surface layer and disturbances in the induced field caused by defects in the steel stock are detected and recorded by pick-ups.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.