| 摘要 |
PURPOSE:To perform flaw detection of high precision with simple comstitution by permitting ultrasonic-wave probes provided in parallel in the direction of the width of a weld zone and slidable along the weld zone to make a judgement corresponding to the magnitude of a received defective echo from a prescribed area and its frequency. CONSTITUTION:Ultrasonic-wave probes 3... provided under the water in a container in parallel in the width direction of weld zone 2 are moved along weld zone 2. Received defective echoes from those probes 3... are passed through gate circuits 11... whose open times are set previously to obtain defective echo signal from areas assigned to probes 3..., and flaw discriminating circuit 12... remove low-level noise inputs. Next, flaw-grade discriminating circuit 13 generates signal h1 corresponding to the size of a defect by a comparison with a set value. Frequency n1 of the generation of this signal h1 is counted by counting circuit 15 and arithmetic circuit 14 calculates a discrimination signal corresponding to the size of the defective signal and the frequency of the generation based upon the formula in the figure. Therefore, the spread of the defect, etc., is detected by the relatively simple constitution with high precision. Here, S is unit time. |
