油气管道类裂纹缺陷涡流内检测的可行性
Feasibility of eddy current inline inspection for crack-like defects of oil and gas pipelines
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摘要: 油气管道类裂纹缺陷尤其是内表面的类裂纹缺陷是导致管道失效的主要因素,但由于现有内检测技术的局限性,类裂纹缺陷成为了管道内检测研究的难点。基于电磁涡流技术,选取不同缺陷深度下的管道本体及环焊缝处类裂纹,通过自主搭建的高速自动涡流检测试验装置开展了不同类型的类裂纹涡流内检测试验,分析了类裂纹缺陷的涡流信号特征,验证了电磁涡流技术用于类裂纹缺陷内检测的可行性。试验结果表明:在较高的检测速度下,通过缺陷阻抗信号可以区分油气管道不同位置的类裂纹缺陷,且随着缺陷深度增大,信号特征越明显;随着缺陷提离值增大,信号特征逐渐减弱;缺陷信号信噪比水平较高,可以满足准确识别类裂纹缺陷的要求。Abstract: The crack-like defects of oil and gas pipelines, especially the crack-like defects on the inner surface, are the main factors leading to pipeline failure. However, due to the limitation of the existing inline inspection technology, the cracklike defects are difficult to detect through inline inspection. Herein, various eddy current inline inspection tests of crack-like defects were performed by setting up an eddy current high-speed automatic testing device to detect the crack-like defects in the pipe body and girth weld at different defect depths based on the electromagnetic eddy current technology. In addition, the eddy current signal characteristics of crack-like defects were analyzed, and the feasibility of applying electromagnetic eddy current technology to the inline inspection of crack-like defects was verified. The test results show that the crack-like defects of oil and gas pipelines at different locations can be distinguished by the impedance signal of defects at a higher inspection speed. Meanwhile, the signal characteristics become more obvious with the increase of defect depth, but attenuate with the increasing of the liftoff value of defects. In addition, the greater signal-to-noise ratio of defect signal can satisfy the requirements for accurately identifying the crack-like defects.