ULTRASONIC INSPECTION SYSTEM FOR THIN METAL PLATE

摘要

PURPOSE: To detect a microdefect in a thin metal plate by generating a specified ultrasonic wave from an ultrasonic transmitter/receiver and setting a specified incident angle of the ultrasonic wave to the thin metal plate. CONSTITUTION: An oscillator oscillates an exciting signal and transmits an ultrasonic wave of 5.5-15 MHz to an oscillator 5. When an ultrasonic beam 37 from the oscillator 5 passes through a liquid filled in a rubber tire 3 and enters into a thin metal plate 31 at a specified angle for generating a plate wave 33 in A0 . mode, a plate wave 33 is generated in the thin metal plate 31. The plate wave 33 is reflected on a defect 35 in the thin metal plate 31 and back the incident path to the oscillator 5 which then generates a detection signal corresponding to the plate wave 33. The detection signal is amplified through an preamplifier and fed to an ultrasonic inspection unit 1 which drives a monitor depending on the detection signal. With such constitution, a microdefect having diameter as small as 0.1mm can be detected in the thin metal plate 31 by observing the waveform on the monitor while carrying the thin metal plate 31.