Assessment of steel inclusions cleanliness by mixed NDT methods
The present project aims to combine new technologies for evaluation of the macroscopic cleanliness of steel products. Microradiography, new ultrasound applications and data fusion technique (US and radio) developments yield very performant tools for the detection of internal defects on as-cast samples, making it possible to understand their origin mechanisms, even under the skin zone. US modelling and 3D processing bring in significant progress. The development of data fusion techniques will be of interest, in particular for automatic inspection, but the application to US and radio did not succeed. With a GMR-sensor it is possible to detect dynamically non-metallic inclusions (alumina) in a cold strip sample with a thickness of 0.8 mm. For a sensor lift-off of 0.5 mm and a strip speed of 0.85 m/s, the detectability limit is reached. Numerical modelling showed that the signal decreases only by 17 % when the speed increases to 40 m/s. It is also possible to use GMR to detect surface and subsurface defects. The comparison program of the different test techniques available showed a weak relation between the results. - The ReinHUS procedure (MIDAS) gives an early assessment of the cleanliness but does not take into account later possible changes in the inclusion morphology. - The ODL system (Lamb waves) offers an assessment at least in time to sort out hot strip coils but seems to be dependent an other parameters. - The IDD method (magnetic flux leakage) has the highest sensitivity, but the result is available just too late.
Bibliographic Reference: EUR 21729 EN (2005), 101 pp. Euro: 25
Availability: http://bookshop.europa.eu/is-bin/INTERSHOP.enfinity/WFS/EU-Bookshop-Site/en_GB/-/EUR/ViewPublication-Start?PublicationKey=KINA21729 (Catalogue Number: KI-NA-21729-EN-S)
ISBN: ISBN 92-894-9875-7
Record Number: 200618442 / Last updated on: 2005-12-15
Original language: en
Available languages: en