| 摘要 |
The method relates to the detection and evaluation of defects occurring on the walls of metal tubes with internal helical ribs. …<??>It uses ultrasonic detection and evaluation means to determine the length of the go-and-return path taken by an ultrasonic beam corresponding to the signal from each defect received by an ultrasonic transceiver ER. Before comparing the amplitude of the signal with a predetermined threshold, a correction is applied to one of the comparison terms so as to take into account the length of the path taken by the signal. …<??>Application to the inspection of heat-exchanger tubes. …<IMAGE>… |
