Research On The Recognition Technology Of The Magnetic Flux Leakage Produced By Defects And Pipeline Components

Pipeline transportation is an important way to transport raw materials and medium in the petroleum and chemical industry. After prolonged use,there will be localized pits caused by corrosion in the pipeline,more serious is the leakage and environmental pollution. Therefore,the non-destructive testing technology of pipeline has great significance for ensuring the safety of industrial production. Now,Ultrasonic Testing,Eddy Current Testing and Magnetic Flux Leakage Testing has been widely used in pipeline inspection technology. In this paper,the main object is Pipeline Magnetic Flux Leakage Testing,analysis the changes in magnetic flux leakage under different circumstances.Nowadays,scholars both at home and abroad are all focused on defects of Pipeline in the technology research Magnetic Flux Leakage Testing,but only a few studies on the impact of Pipeline components,such as pipeline repair fill plates,flanges,branch pipe,and weld. Because the structural characteristics of these pipeline parts,they also produce magnetic flux leakage if being magnetized,it will be result in mistake,missing and reducing the accuracy of detection if the leakage magnetic field generated by these components confused with the defects,also brought a lot of inconvenience for pipeline inspection and maintenance. For these questions,in this paper,using finite element method of numerical analysis and experimental method to analysis the characteristics relationship between the shape parameter and the magnetic flux leakage,and the difference between magnetic flux leakage of the defect and parts.Based on the basic principle of magnetic flux leakage testing,analysis of the main components of the signal measured by the sensors in the process of magnetic flux leakage testing,they are the magnetic flux leakage field and the field coupling by permanent magnet in air. Lay the theoretical foundation for the identification of the defect leakage magnetic field and magnetic flux leakage produced by the pipeline components. Obtain the characteristic parameters of the leakage magnetic field by the finite element analysis of defects,fill plates,flanges,weld and branch pipe. And design the magnetic flux leakage detector use the size of magnetization equipment in the finite element calculations. Obtain the difference of the magnetic flux leakage signals between defects and pipe components. Finally,provide a theoretical basis for identifying magnetic flux leakage signal of defects and pipeline components by contrast the results of experimental data and finite element analysis.