High Sensitivity EMAT System using Chirp Pulse Compression and Its Application to Crater End Detection in Continuous Casting

3rd International Symposium on Laser Ultrasonics and Advanced Sensing

Iizuka, Y.^1 ; Awajiya, Y.^1,2

Steel Research Laboratory, JFE Steel Corporation, 1-1, Minamiwatarida-cho, Kawasaki-ku, Kawasaki, 210-0855, Japan^1

Steel Research Laboratory, JFE Steel Corporation, 1, Kawasaki-cho, Chuo-ku, Chiba, 260-0835, Japan^2

关键词: Chirp-pulse-compression;    Continuous casters;    High sensitivity;    ITS applications;    Received signals;    Signal amplitude;    Surface cooling;    Synchronous averaging;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/520/1/012011/pdf
DOI  :  10.1088/1742-6596/520/1/012011

来源: IOP

【 摘 要 】

A high sensitivity EMAT system using chirp pulse compression technique was developed. The system uses a high power gated amplifier having 2kVpp output to transmit chirp waves. Pulse compression of the received signals are performed digitally in a PC after amplification and analog-to-digital conversion. A 20dB improvement of the signal-to-noise ratio was achieved by chirp pulse compression and synchronous averaging. A new surface cooling technique was also developed to improve the signal amplitude of the bulk shear wave with hot steel, and its effectiveness was demonstrated. An actual plant test of crater end detection by the developed EMAT system was conducted at a continuous caster, and clear detection by non-contact EMATs was achieved.