PPM TYPE ELECTROMAGNETIC ULTRASONIC TRANSDUCER, ULTRASONIC FLAW DETECTING METHOD USING IT AND ULTRASONIC FLAW DETECTOR

摘要

PROBLEM TO BE SOLVED: To detect a spherical microflaw by enhancing sensitivity in a case the SH wave transmitted along a surface is transmitted and received by a PPM type electromagnetic ultrasonic transducer by providing a transducer structure capable of increasing an aperture diameter.;SOLUTION: The PPM type electromagnetic ultrasonic transducer is equipped with a magnet array 10 wherein fan-shaped alternating magnetic field forming magnet rows 14a-14d, wherein a large number of permanent magnets 12 reversed in polarity in an up and down direction and having an arcuate shape are arranged so as to be changed in polarity alternately, are arranged in an annular shape in adjacent relationship so as to become different in the phase of polarity, a transmitting spiral coil 30 having radial components going toward the center of the annular shape in the magnet array and having an almost 8-outer shape and a receiving spiral coil 40 provided at a position where the transmitting spiral coil is rotated by a predetermined angle and having the same shape as the transmitting spiral coil.;COPYRIGHT: (C)2006,JPO&NCIPI