PURPOSE: To dispense with surface treatment of a body to be inspected and to make it possible to execut flaw detection with high sensitivity by providing a plurality of transmission/reception coils divided electrically and by switching over the coils electrically for scanning.
CONSTITUTION: Transmission/reception coils 5 are divided into two transmission/ reception coil groups and provided at symmetric positions on the opposite sides of a welded part W of a metal 4 bring a body to be inspected. Since the equipment is of an electromagnetic type, surface treatment is dispensed with basically and, in addition, a probe can be removed simply from the surface of the body 4 to be inspected by interrupting an exciting current, while a magnetic flux density can also be increased. Since an angle of refraction of an ultrasonic wave propagated through the body 4 to be inspected is determined by the relation between a coil pitch and a frequency, moreover, a desired frequency can be set according to setting of the coil pitch. Since the coils 5 are juxtaposed in the direction intersecting the direction of propagation of the ultrasonic wave perpendicularly to it in addition, scanning can be executed with the juxtaposed coils 5 switched over electrically, and therefore flaw detection over a wide range can be executed without being accompanied by mechanical movement.
TAWARAGUCHI TAKAO
KAWAMURA KOJI
HAYASHI KAZUO
AKAGI TOSHIO
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