| 摘要 |
PURPOSE:To provide an apparatus wherein an object, to be inspected, whose crystal grain size is larger than a sheet thickness can be measured quickly in a production line out of apparatuses wherein the crystal grain size is measured nondestructively by an ultrasonic method. CONSTITUTION:A probe 1 is formed to be of a convergence type, and the convergence diameter of ultrasonic pulses is made sufficiently narrower than a crystal grain size. An object 5 to be inspected is scanned fine by a scanning mechanism 2. A sound-velocity operation device 4 measures a longitudinal-wave sound velocity continuously, and a difference in the sound velocity by a crystal orientation is analyzed. Even when a horizontal distance is changed a little, the sound velocity can be measured. As a result, the object to be inspected can be measured accurately not only in a case where it stands still but also in a case where it is moved at high speed while it is being vibrated. |
