Ultrasonic test on the heat shrinkable tapes used in the field coating for welded joints of pipeline

To test the peel strength of heat shrinkable tapes used in the field coating for welded joints of pipeline, artificial sampling is often inefficient and decided by human factors. In this regard, based on the ultrasonic theory analysis and the experimental analysis of test specimen of pipeline welded joint with different bonding strengths, the ultrasonic test technique is used in nondestructive testing of bonding quality of heat shrinkable tapes, so as to qualitatively and semi-quantitatively evaluate the peel strengths. Then, the ultrasonic characteristic parameters which can clearly reflect the peel strength of heat shrinkable tapes are identified. The research shows that both average power and low frequency energy of ultrasonic signal are inversely proportional to the peel strength, which can used to detect the peel strength comprehensively and rapidly. In view of these two parameters, the test result of welded joint sample with the ultrasonic wave reflection method agrees with the manual mechanical tensile test, verifying the effectiveness of such parameters. Ultrasonic characteristic parameters can provide a reference to the ultrasonic non-destructive test of bonding quality of heat shrinkable tape.