基于B扫描成像的油气对焊弯管缺陷的超声导波检测

Ultrasonic Guided Wave Inspection of Defects in Oil and Gas Butt-Welded Bend Based on B-scan Imaging

为解决应用超声导波检出油气对焊弯管缺陷的难题,分析了弯头及环焊缝对L(0,2)模态、T(0,1)模态导波的传播影响,发现环焊缝会使导波产生反射,弯头及环焊缝会使导波产生衰减和模态转换,而导致油气对焊弯管缺陷难以检出;提出了基于B扫描成像的超声导波检测方法,通过B扫描图像辅助识别弯管缺陷信号;最后加工了2根带缺陷的油气对焊弯管,采用上述方法进行检测试验。试验结果表明,基于B扫描成像的超声导波检测方法能够有效检测并定位出弯头及过弯头后直管上的缺陷。

In order to inspect the defect in the oil and gas butt-welded bend by ultrasonic guided wave,the influence of elbow and girth weld on the propagation of L(0,2)mode and T(0,1)mode was firstly analyzed.It is found that the girth weld causes the reflection of ultrasonic guided wave,meanwhile,the elbow and girth weld cause the attenuation and mode conversion of ultrasonic guided wave.The above phenomenon makes it difficult to inspect the defect in the oil and gas butt-welded bend.Then,the method of ultrasonic guided wave inspection based on Bscan imaging is proposed,which was used to assist the identification of the defect signal by the B-scan image.Finally,two oil and gas butt-welded bends with defects were processed,and the above method was used for the test.The experimental results show that the method of ultrasonic guided wave inspection based on B-scan imaging can effectively inspect and locate the defects in elbow and in the straight pipe after the elbow.