Patent ID: 8495915

Claim:
A method for performing ultrasonic testing comprising the steps of: arranging an ultrasonic probe which comes in an ultrasonic phased array probe in which a plurality of transducers are arrayed so as to face an external surface of a tubular test object; setting a circumferential angle of incidence αi of an ultrasonic wave to be transmitted from said ultrasonic probe upon said tubular test object and an axial angle of incidence βi of the ultrasonic wave to be transmitted from said ultrasonic probe upon said tubular test object based on a ratio of thickness to outer diameter t/D of said tubular test object so that an internal refraction angle θk calculated from said circumferential angle of incidence αi, said axial angle of incidence βi, and said ratio of thickness to outer diameter t/D of the tubular test object may be not less than 35° and not more than 60°; transmitting an ultrasonic wave to said tubular test object from said ultrasonic probe in which said circumferential angle of incidence αi and said axial angle of incidence βi are set; receiving an ultrasonic wave reflected from said tubular test object by said ultrasonic probe; and processing the received ultrasonic wave to detect a flaw on said tubular test object, wherein in the step of setting said circumferential angle of incidence αi and said axial angle of incidence βi, by electrically controlling transmission time-shift or reception time-shift of an ultrasonic wave by said plurality of transducers, at least one of said circumferential angle of incidence αi and said axial angle of incidence βi of the ultrasonic wave transmitted to said tubular test object is electrically adjusted.