针对地面管道的运行特点，基于漏磁检测技术理论，设计了一种适用于多种管径的管道外部自动检测装置，并通过有限元仿真和试验，对管壁上不同深度和直径的腐蚀缺陷进行模拟和检测，分别得到了管道缺陷的不同参数对漏磁场的影响规律。仿真和试验结果具有一致性。另外，从管道内、外壁缺陷检测结果看，所设计的漏磁检测仪对管道内、外壁缺陷的检测同样有效。

According to the operational characteristics of the ground pipeline and based on the theory of magnetic flux leakage testing technique, an automatic detection device on the outside of pipeline was designed, which was suitable for different diameters of pipelines. Then the corrosion defects with different depth and diameter on the wall of pipeline were simulated and tested through the finite element simulation and experimental research, and thereafter the influence law of different parameters on the leakage magnetic field was obtained. The results of simulation and experiment are consistent. In addition, according to the results of defect detection, the designed magnetic flux leakage detector is effective for the detection of defects both in inner and in outer walls of the pipeline.