METHOD AND APPARATUS FOR ULTRASONIC FLAW DETECTION

摘要

A method and apparatus for ultrasonic flaw detection of line focus type suitable for detection of flaws in nonmetallic materials included in an object. Ultrasonic transmitter and receiver elements of line focus type are opposed at a distance (L) with an object under test placed between them, and a maximum ultrasonic echo is obtained at a distance Lp expressed by: Lp=0.75(FT+FR)-{(CS/CW)-1}t where FT (mm) is the focal length in the medium of the ultrasonic transmitter element of line focus type, FR (mm) is the focal length in the medium of the ultrasonic receiver element of line focus type, CS (m/sec) is the speed of ultrasound in an object under test, CW (m/sec) is the speed of ultrasound in the medium, and t (mm) is the thickness of the object under test.