| 摘要 |
PURPOSE:To perform measurement effectively, by a method wherein a material to be inspected is used as a core and wound by an exciting coil to act magnetomotive parallelly. CONSTITUTION:DC magnetic flux generated by two DC coils 11, 12 is passed through the interior of a material 1 to be inspected and the direction thereof is made parallel with the surface thereof. That is, magnetic flux forms a magnetic field of a component parallel to the surface necessary in transmitting and receiving almost all longitudinal electromagnetic ultrasonic waves. Therefore, if an exciting amount is increased, the intensity of the magnetic field is increased almost proportionally to obtain a value of 10,000 Gauss or more. By this method, the enhancement in the detection signal level of longitudinal electromagnetic ultrasonic waves is attained. |
