| 摘要 |
PURPOSE: To inspect a material accurate on-line by obtaining the propagating velocity of an ultrasonic wave in three or more different directions on the surface of a metal material, and deciding the material failure from the velocity difference from reference propagating velocities of the directions which have been previously obtained. CONSTITUTION: Transmitting elements 1-3 generate ultrasonic waves according to a signal from a pulser 4, and propagates them in the three directions on the surface of a steel plate, i.e., a passing plate (X) direction, a 45-degree (Y) direction to the plate and a (Z) direction perpendicular to the plate. Receiving elements 11-13 receive them, and send reception signals to arithmetic units 21-23. The units 21-23 measures time differences Tx -Tz between the signal of the pulser 4 and the signals of the elements 11-13, obtains speeds Vx -Vz of the Y, Y and Z directions from the distances between the elements 1-3 and the elements 11-13, and sends them to an arithmetic apparatus 30. The apparatus 30 obtains the speed ratio of them to reference propagating velocities Vox -Voz of the respective directions thus obtained, compares them with the ratios, and judges abnormal when all are threshold values or less and normal except them. |
