Research On The Leakage Magnetic Inspection Technology Of Special Pipeline

With the development of the times, oil, gas and other energy are playing more and more important role in the national economy. Pipeline transportation as petroleum, chemical industry, the most important means of energy transmission, is bound to become one of the concerns around the world. Because the pipeline for long-term use, it will be among the corrosion degree, if not timely detection, once leakage accidents, whether from economic Angle or from the perspective of the environment will have serious consequences. Therefore, the use of non-destructive testing techniques for the detection of pipeline in service to ensure the safety of industrial production has a great significance.Widely used by domestic and international pipeline inspection technologies include ultrasonic testing, eddy current and magnetic flux leakage testing of several. In this paper, the magnetic flux leakage detection, as the research object, analyzes the different circumstances in the pipeline leakage magnetic field changes. For the pipeline magnetic flux leakage detection technology, scholars at home and abroad focus on wall defect, while ignore the other parts such as scar, fill welding seam , elbow and other special pipe in research, In the practical detection, it can affect the accuracy of the test results, and even the wrong result. Because these parts of the structure characteristics, in the pipeline was magnetized also can produce leakage magnetic field , If ignore these parts of the leakage magnetic field generated by the study, it is easy to be confused with the defect leakage field, which gives pipeline inspection and maintenance brought a lot of inconvenience.In this paper, finite element analysis method to analyze parameters of pipeline defects and leakage characteristics of the relationship between magnetic field and magnetic flux leakage defect management with special conditions the difference between the leakage field. According to the basic principles of magnetic flux leakage testing, using ANSYS simulation software, the establishment of the pipe diameter of 720mm solid model detector, pipe welding and weld defects normal physical model for the simulation analysis, the ring size of weld defects in 8mm, 5mm, and 2mm under the simulation results. Rectangular fill pipelines scar on the corresponding simulation, select the two cases, respectively, make up scar thickness of 10mm and 20mm case, they have come to the characteristics of magnetic flux leakage signal. Pipe leakage magnetic field from the finite element analysis of leakage magnetic field obtained defect leakage field and pipeline components of leakage magnetic field distribution. Use of simulation results, the data acquisition capabilities with ANSYS to simulate the pipeline within the detector in the sensor operation, define the path for data collection, the corresponding curves drawn map, the results of comparative analysis, as detected in the latter part of the pipeline data processing, the distinction between special conditions on the tube to provide theoretical basis for the case of injury.