ULTRASONIC FLAW DETECTOR AND ULTRASONIC FLAW DETECTION METHOD BASED ON TOFD FLAW DETECTION TECHNIQUE

摘要

PROBLEM TO BE SOLVED: To provide an ultrasonic flaw detector and an ultrasonic flaw detection method based on the TOFD flaw detection technique, capable of entering a strong acoustic pressure into a test piece even if waviness or the like is present on the surface of the test piece, and highly accurately detecting a minor flaw within the test piece by a flaw detection waveform obtained by the incidence of the strong acoustic pressure and having an excellent SN ratio.SOLUTION: An ultrasonic flaw detector comprises: a holder 14 that supports a pair of wedges 12 so that the wedges 12 can oscillate about rotation axes a-a thereof parallel to each other; a transmission-side probe 16 that is fixed to a facing surface 12b of one of the wedges 12 and that transmits an ultrasonic beam S toward a contact surface 12a of the wedge 12; and a reception-side probe 18 that is fixed to a facing surface 12b of the other wedge 12 and that receives an ultrasonic beam S from a contact surface 12a of the other wedge 12. The contact surfaces 12a of the paired wedges 12 are formed to be able to be closely attached to the waviness of a test piece surface 1 when being located along the test piece surface 1, and the rotation axes a-a are located on normal lines of the contact surfaces 12a and in parallel to the contact surfaces 12, respectively.SELECTED DRAWING: Figure 8