Inner defect detection system and detection method of steel plate using nonlinear ultrasonic generation

摘要

PURPOSE: A system for detecting inner defect of steel strip using non-linear ultrasonic generation is provided to detect minute internal defect inside a steel sheet using nonlinear ultrasonic wave. CONSTITUTION: A system for detecting inner defect of steel strip using non-linear ultrasonic generation comprises an ultrasonic transmitter(1000), an ultrasonic receiver(2000), and a signal processing unit(500). The ultrasonic transmitter generates ultrasonic plate wave to the inside of a rolling steel sheet through online. The ultrasonic receiver receives the ultrasonic plate transmitted in the width direction of the steel sheet through online. The ultrasonic receiver filters and amplifies ultrasonic plate wave of specific frequency band among ultrasonic plate waves. The signal processing unit obtains the value of the nonlinear parameter from the first high frequency and the second high frequency which is identical with the ultrasonic plate wave.