（Mechanical Science And Engineering College, Da Qing Petroleum Institute, Daqing, 163318）
An experimental system is set up in a laboratory which
is based on ultrasonic-acoustic emission inspection. Propagation characteristics
of ultrasonic waves are studied under several defect conditions. The signals from the testing are analyze
d with STFT and wavelet analysis methods. The result shows that the defects detected by AET can be locate
d exactly with ultrasonic method, and that with UT we can get more defect information, which set up the basis for engineering application.
Keywords：Pipe，Acoustic emission，Ultrasonic，Wavelet analysis