Surface inspection of heavy plates using electromagnetically generated ultrasonic waves
The main aim of this research project was to establish a basic method to use e.m.a. Rayleigh wave probes for the surface inspection of heavy plates in the production process. The EMAT was optimised with respect to necessary sensitivity, frequency, axial resolution, wear resistance and compact probe size. The sensitivity of the frequency optimised Rayleigh wave probe is sufficient to detect a 0.3 mm deep and 10 mm long model defect in a distance of 300 mm. For the automated inspection the ALOK-system has been adapted in a laboratory prototype for the surface inspection of heavy plates by Rayleigh waves. This equipment consists of an ultrasonic hardware device for fast data-acquisition and preprocessing (essential data reduction) according to the ALOK-algorithm, and a computer to achieve noise- and ghost-elimination as well as defect imaging and reconstruction. The ALOK-4 prototype and the newly developed probe were successfully used in laboratory inspections as well as in random tests in a rolling mill.
Bibliographic Reference: EUR 12415 DE (1990) 110 pp., MF, ECU 8, blow-up copy ECU 13.75
Record Number: 199010956 / Last updated on: 1994-12-01
Original language: de
Available languages: de