CRYSTAL GRAIN MEASURING METHOD AND DEVICE FOR METAL SHEET

摘要

PROBLEM TO BE SOLVED: To provide a measuring method and a device for the crystal grain size of a metal sheet capable of measuring the crystal grain size quickly without reducing measurement precision even in the case where the thickness of a test body is thin. SOLUTION: A waveform from a wide-band waveform generation means 2 is given to an electromagnetic ultrasonic sensor 5, and the received wave is inputted into a frequency analytical means 8 to obtain a spectrum. The spectrum obtained by the frequency analytical means 8 is transmitted to a waveform operation processing means 9 to obtain an attenuation coefficientαin a resonance frequency. A crystal grain size calculation means 10 calculates the crystal grain size based on the attenuation coefficient in the resonance frequency obtained by the waveform processing means 9.