Automatische Erkennung von oberflachennahen fehlern an kaltgewaltzen Bandern mit Ultraschall
Modern production speeds and quality standards associated with the continuous processing of steel products require high-speed, sensitive monitoring systems and the use of increasingly effective non-contact monitoring systems based on ultra-sound has been found advantageous. Free waves have been replaced by guided waves while electro-magnetic transducers have supplanted the earlier piezzo-electric devices, despite problems in maintaining a small but precise air-gap. Guided elastic waves which produce both longitudinal and transverse waves offer special advantages. The free-wave "AVG"-system offers both quantitative and qualitative assessment in a continuous manner, providing an estimate of the size of the detected faults. Development of an analogous system using guided waves is difficult because of the different physics involved but the concept is receiving serious attention with the objective of developing a reliable on-line testing-head which will both detect and classify faults - and possibly be able to distinguish between surface and internal faults. Prototype test heads have been developed and evaluated but a proper understanding of the precise nature of the underlying physics is an essential prerequisite to further progress in the development of practical systems.
Bibliographic Reference: EUR 18518 DE (1998) 155pp.
Availability: Available from OOPEC Sales agents
ISBN: ISBN 92-828-4780-2
Record Number: 199910883 / Last updated on: 1999-07-05
Original language: de
Available languages: de