Experimental Investigation on Thick Wall Pipes Based on Circumferential Guided Waves Inspection Technology
厚壁管道周向导波检测技术实验研究

Thick wall pipes are the core component of so called "four pipe" system for thermal power.It is important to apply circumferential guided wave technique to nondestructive testing of thick wall pipes.Firstly,the excitation method for thick wall pipes inspection needs to be determined.The combination of probe with 0.5 MHz excitation frequency and wedge with 60° angle is the optimized selection.By adjusting the circumferential distance between the angle beam probe and the axial defects of the outer wall,the defect echo was still detected within a certain range,and the received circumferential echo amplitude fluctuated unconspicuouse,which indicates that circumferential guided waves have the potentials to perform nondestructive testing for thick wall pipes.Through translating the angle beam probe 20mm along the axial direction,the axial defects are not covered by circumferential excitation of angle beam probe,so the defects are not detected.This indicates that the propagation of circumferential guided waves around the thick wall pipes is directional.Above results provide a basis for the characteristics of circumferential guided waves around the thick wall pipes and nondestructive inspection of thick wall pipes based on circumferential guided waves.