Simulation and Experimental Research on Magnetic Flux Leakage Detection Method of Long-distance Pipeline Local Dents Stress

The mechanical damage of the pipeline will cause local dents of the pipe wall, accompanied by different levels of localized stresses. In this paper, the magnetic flux leakage detection technology is used to simulate and test the local dents of pipeline mechanical damage. The magnetic field distribution of the magnetic leakage detection is observed in the local stress loading state of the pipeline mechanical damage. Meanwhile, it is modeled and analyzed the equivalent change and detection effect of the magnetic flux density in the leakage magnetic field in the state that the pipeline mechanical damage is at different degree stress loading. Then the experiment is conducted with reference to the simulation results. Simulated artificial injuries with different deformation degrees of local dents are processed on the Φ323.9 steel pipe. It conducted magnetic flux leakage detection on local dents of pipeline mechanical damage by parameters of different DC magnetization strength. It showed that the leakage magnetic field effect of 5% OD pipeline mechanical damage local dents is better than 0.5% OD and 1% OD.