| 摘要 |
PROBLEM TO BE SOLVED: To make easily inspectable the thickness, the diameter, the surface state, the corrosion state or the like of an object to be inspected, by inspecting the thickness or the diameter of the object to be inspected in a direction at right angles to the propagation direction of ultrasonic waves on the basis of a correlation between the thickness or the diameter of the object to be inspected in the direction at right angles to the propagation direction of the ultrasonic waves and the peak frequency of the ultrasonic waves. SOLUTION: The web 5 of an H-steel plate H which is covered with cover plates 7 and side plats 8 such as, e.g. a covered steel plate 3 is used as an object to be inspected. Ultrasonic waves are introduced from one end of the web 5 by an ultrasonic probe 2. Reflected waves from the halfway part or the other end of the web 5 are received by the probe 2. The frequency of the ultrasonic waves which are propagated in the object to be inspected has a correlation with the thickness or the diameter of the object to be inspected (the thickness of a plate or the thickness of a rod). The minimum frequency (the peak frequency) of the ultrasonic waves which can transmit the object, to be inspected, in a prescribed thickness or a prescribed diameter exists. Then, when a correlation between the frequency of the ultrasonic waves and the thickness or the diameter of the object to be inspected is used, it is possible to measure the thickness or the diameter of the object to be inspected. |
