| 摘要 |
PROBLEM TO BE SOLVED: To provide a device and a method measuring a crystal grain diameter of a steel plate online by adapting a laser ultrasonic wave method in a production line of the steel plate. SOLUTION: The online crystal particle grain diameter measuring device is composed of: a pulse light emitting laser, a laser for ultrasonic measurement, an optical fiber 33, and an optical fiber 41; an optical head 70 irradiating a light beam of the pulse light emitting laser on a surface of a measuring object to generate an ultrasonic wave, irradiating a light beam of the laser for ultrasonic measurement transmitted by the optical fiber 33 to the same position as a generating position of the ultrasonic wave, collecting scattered light reflected by a reflected ultrasonic wave of the ultrasonic wave, and sending it into the optical fiber 41; an ultrasonic stable measuring part provided with a confocal Fabry-Perot interferometer and a high speed shutter to detect intensity change of the scattered light transmitted by the optical fiber 41 and measure strength of the reflected ultrasonic wave; and a signal processing part calculating the crystal grain diameter from an electrical output signal of the ultrasonic stable measuring part. COPYRIGHT: (C)2006,JPO&NCIPI
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