Shenyang University of Technology has successfully developed an omnidirectional ultra-high-definition magnetic flux leakage internal detection system for long-distance pipelines

Magnetic flux leakage detection refers to the formation of the magnetic leakage field on the surface of ferromagnetic material due to the defects on the surface or near the surface of the specimen after magnetization. People can detect defects by detecting the changes of the magnetic leakage field. The so-called leakage magnetic field is that when the material has the defect of cutting magnetic line, the surface defect or the change of tissue state will change the permeability. Because the permeability of the defect is very small and the magnetoresistance is very large, the flux in the magnetic circuit will be distorted and the flow direction of the magnetic induction line will change, except that part of the flux will pass through the defect directly. Otherwise, some magnetic flux will leak to the surface of the material to bypass the defect, and then enter the material through the air to bypass the defect, thus forming a leakage magnetic field on the surface of the material.

Magnetic flux leakage testing is a very important non-destructive testing method, which is widely used. When it is used in combination with other methods, it can provide fast and inexpensive evaluation for ferromagnetic materials. With the progress of technology, people pay more and more attention to the automation of the detection process. This can not only reduce the labor intensity of testing work but also improve the reliability of testing results and reduce the impact of human factors.

At present, the confidence of pipeline internal magnetic flux leakage testing equipment at home and abroad is 80%. The main reason is that the existing pipeline internal magnetic flux leakage testing technology can not detect axial defects, pipe body cracks and weld cracks. In order to solve this problem, Professor Yang Lijian of the Shenyang University of Technology led the research team of on-line detection of oil and gas pipelines, developed an all-round ultra-high-definition magnetic flux leakage internal detection system for long-distance pipelines with independent intellectual property rights. The success of the system test marks that our country has mastered the all-directional ultra-high-definition magnetic flux leakage detection method of the pipeline, which makes the pipeline detection technology more systematic and scientific, makes up for the domestic blank and makes the pipeline detection technology of our country step into the international leading level.