|
|
|
Abstracts
|
|
Authors
Hirao, M; Fukuoka, H; Fujisawa, K; Muryama, R
|
Title
On-Line Measurement of Steel Sheet r-Value Using Magnetostrictive-Type EMAT
|
Journal
Journal of NDE Vol 12 No 1 1993 pp 27-32
|
Abstract:An ultrasonic on-line system to measure r values in cold rolled steel sheets has been developed with electromagnetic acoustic transducers (EMATs). These EMATs are composed of meanderline coils and electomagnets and operate with magnetostrictive mechanism. The EMAT instrument measures propagation times of the fundamental symmetrical Lamb wave at a low frequency and relates them to the r values through a calibrated regression curve. Preliminary tests indicate that the on-line monitoring of r is quite feasible with a standard deviation of 0.07 for various low carbon steel sheet; the thicknesses range from 0.5 mm to 2.5 mm. The measuring time is 20 msec per data. The liftoff is allowed to 5 mm with 2 mm thick sheet. The r evaluation is independent of the line speed up to 325 m/min. These promising results promote installation of ultrasonic r value measurement systems in steel production lines.
|
RITEC Inc.
60 Alhambra Road Suite 5 Warwick, RI 02886 |