DETECTION OF INCOMPLETE PENETRATION AND FATIGUE CRACK OF SOCKET WELDED PART BY ULTRASONIC FLAW DETECTION APPARATUS

PROBLEM TO BE SOLVED: To enable the high reliable flaw detection work of a socket welded part by receiving the reflected beam caused by incomplete penetration or a fatigue crack to analyze data to also estimate even the shape of a damage. SOLUTION: A beam (a) composed of the ultrasonic waves emitted from a transmission part 61 is incident on a socket 11 at a predetermined incident angle α1 to reach a socket welded part 14 and, if a flaw, that is, incomplete inferiority 15 or a fatigue crack 16 is present in the socket welded part 14, a flaw echo is generated. The reflected beam (b) composed of this flaw echo is received by a receiving part 62 and the received signal is sent to a control unit to be subjected to data processing and the processed data is displayed on a CRT as an echo height distribution drawing. Therefore, the presence or shape of incomplete penetration 15 or the fatigue crack 16 can be estimated or confirmed. Therefore, the reliability of flaw detection work in the socket welded part can be enhanced.