漏磁探伤规律用于油气管道的缺陷检测

Defect Detection of Oil and Gas Pipelines by Magnetic Flux Leakage Testing

油气管道在服役过程中会产生某些类型的缺陷,根据缺陷性质和产生的部位,采用超声、磁粉、涡流、漏磁等无损检测方法对管道缺陷进行检测,其中漏磁检测是比较好的检测方法,可检测管体的裂纹、孔洞、磨损等缺陷。通过探测漏磁场来获取缺陷漏磁场的量值,从而可对缺陷进行量化,实现缺陷识别智能化。漏磁探伤有以下规律性:同等大小的缺陷,上端距工件表面距离越近,产生的漏磁场越大;缺陷方向越接近垂直于磁场方向,漏磁场越大;同样宽度的缺陷,如果深度不同,产生的漏磁场不同。对检测波形进行分析,验证了漏磁检测的规律性,为实施油气管道整体评价提供了依据。

Some types of defects will be produced in the service of oil and gas pipelines. Defects are detected by ultrasonic, magnetic powder, eddy current, magnetic flux leakage and other non destructive testing methods according to the nature of the defects and the parts produced. The magnetic flux leakage detection method can detect the crack, hole, wear and other defects of the pipe body. By detecting the leakage magnetic field, the value of the magnetic flux leakage field can be obtained, and the defects can be quantified, and the intelligent of the defect identification can be realized. Magnetic flux leakage testing has the following rules： The same size of the defect, the upper end of the distance from the surface of the work piece closer, resulting in leakage of magnetic field, the more close to the direction of the defect perpendicular to the direction of the magnetic field, the larger the leakage field; The same width of the defect, if the depth of the different, resulting from the leakage of＂ magnetic field is different. Through the analysis of the test waveform, the three rules of the magnetic flux leakage detection are verified, which provides a basis for the implementation of the overall evaluation of the oil and gas pipeline.