PROCEDURE AND DEVICE FOR VERIFICATION BY ULTRA-SOUNDS OF PINS WITH A JUMP OF WALL THICKNESS

摘要

A method for the ultrasonic testing of bolts for incipient cracks emanating from a wall thickness discontinuity between thinner and thicker parts of the bolt, which includes placing an ultrasound transmitter and receiver in the form of a piezo-electric transducer on the periphery of the thicker part of the bolt with the discontinuity located in the near-field region, radiating longitudinal waves at an angle of 55 DEG to 70 DEG and transversal waves at an angle of 25 DEG to 35 DEG from the transducer in direction toward the discontinuity, and comparing the intensity of reflected transversal and longitudinal waves with an echo characteristic obtained from a test body corresponding to the bolt to be tested, having slots formed therein simulating incipient cracks of different depths, and an apparatus for carrying out the method.