Method and apparatus of ultrasonic flaw detection

摘要

A method and an apparatus of ultrasonic flaw detection suitable for detecting internal cavern defects of a material, the method involving the mounting on a rotary body of a plural number of skew probes in equidistant positions in the circumferential direction of the rotary body to provide a corresponding number of channels for transmitting and receiving ultrasonic beams in a direction intersecting the axis of rotation of the rotary body at different depths in an inspection zone of a material positioned opposingly to the probes. The rotary body is turned to revolve the probes through 360 DEG about the axis of rotation while transmitting and receiving the ultrasonic pulses. Selected flaw patterns are produced from the peak values of the echoes received at the detection gates of the respective channels in relation with the direction of incidence of the ultrasonic beams. The direction, inclination, size and depth of a detected defect is deciphered by correlation processing of the detected flaw patterns with a number of predetermined reference patterns in order to provide for judging the harmfulness of the detected defect.