基于TOFD的管道焊缝无损检测技术研究

Research on Non-destructive Testing Technology of Pipeline Welding Seam Based on Ultrasonic TOFD

在高温、高压、高流速、高腐蚀的环境条件下,油气管道焊缝处易出现各种裂纹和腐蚀缺陷,针对这一问题,采用超声波衍射时差法(TOFD)开展管道焊缝的相关检测。通过在室内人工制造3种缺陷类型,对双面介质差异(有无油层)情况下的TOFD特征及缺陷信号进行了提取,应用小波阈值去噪功能对噪声和有效信号进行处理,在现场实际工况条件下对一段管道的环焊缝以及支架角焊缝进行检测验证。结果表明,TOFD检测技术可以在不卸料、不停产的情况下检测到多处埋藏缺陷和内壁腐蚀情况,较传统射线检测效果更好。该技术成熟后可在其他油田和管道行业推广,从而为管道完整性的评估提供理论依据。

Under the environment of high temperature,high pressure,high flow velocity and high corrosion,various cracks and corrosion defects are easy to appear in the welding seam of oil and gas pipelines.In order to solve this problem,the method of time of flight diffraction(TOFD)is used to carry out related inspection of pipeline welds.Through the indoor artificial three types of defects,the TOFD characteristic and defect signal under conditions of double medium difference(with and without oil layer)are extracted.The noise and effective signal are processed with wavelet threshold de-noising function,and girth welds and bracket fillet welds of a section of pipeline are detected and verified under actual working conditions.The results prove that TOFD detection technology can detect many buried defects and inner wall corrosion without discharging or stopping production,which is better than traditional X-ray detection.The technology can be popularized in other oilfields and pipeline industry after it matures,so as to provide theoretical basis for pipeline integrity assessment.