Abstract: An ultrasonic flaw detection apparatus is equipped with a probe which is driven by a transmission signal and which transmits an ultrasonic pulse at an angle with respect to a surface of a test object. The probe receives an ultrasonic pulse, which has been reflected by a defect in the test object, as an echo. The apparatus further includes a scanner for scanning the probe over a predetermined scanning zone on the test object and for outputting a spatial position of the probe. The apparatus is further equipped with a transmitter-receiver which has a transmitter for generating a transmission signal and outputting the transmission signal to the probe, a position detector for receiving a spatial position of the probe from the scanner, and a signal processor for detecting the defect according to the stored spatial position of the probe and the stored echo, taking the spread of an ultrasonic beam attributable to diffraction into account.

Abstract: An ultrasonic transceiver has a function of displaying a modified B scope. The ultrasonic transceiver transmits ultrasonics to an inner part of a test object at an angle of inclination to a surface of the test object, receives echoes from discontinuity in the test object, and displays, based on an outcome of the reception, an image which shows a state of transmission of the ultrasonics in the test object. When displaying the image, origins of time axes on the screen are shifted through a coordinate transformation of the outcome of reception to avoid the difference in lateral positions of images of single discontinuity. Consequently, it is possible to accurately discern the location, size, configuration, and posture of the discontinuity when the outcome of reception is displayed in a rectangular display window.