| 摘要 |
PURPOSE:To improve inspection accuracy and efficiency by passing an echo signal at a specific frequency using a band-pass filter. CONSTITUTION:The focus of a probe 11 is focused at the position of the bottom surface wave echo of a specimen 12 by a scanner 13. A pulsar/receiver circuit 4 of a flaw-detection part 2 receives the reception signal of echoes and then the output signal is transmitted to a switching circuit 6, where the output signal is selected to be passed either through a bandpass filter 6a or directly 6b. The selected output is changed into a video signal via a detection circuit 7 and is output to a peak-hold circuit 8. By detecting the peak value of echo signals as a first peak, it is stored at a memory 3b. Then, the peak value of a signal where echo signals were passed at a specific frequency using a band-pass filter is stored as a second peak value. Then, a second peak value is normalized by the first peak value and then the value is compared with a specific reference value, thus detrmining that welding is defective when the value is equal to or less than the reference value. |
