ULTRASONIC TESTING METHOD AND MANUFACTURING METHOD OF SEAMLESS PIPE OR TUBE

摘要

A circumferential angle of incidence .alpha.i of an ultrasonic wave transmitted from an ultrasonic probe 1 upon a tubular test object P and an axial angle of incidence .beta.i of the ultrasonic wave transmitted from the ultrasonic probe 1 upon the tubular test object P are set based on a ratio of thickness to outer diameter t/D of the tubular test object P so that an internal refraction angle .theta.k calculated from the circumferential angle of incidence .alpha.i, the axial angle of incidence .beta.i, and the ratio of thickness to outer diameter t/D of the tubular test object may be not less than 35° and not more than 60°.