Study of Detection on Complex Structural Parts of Insulated Pipes Based on Focusing Probe with Pulsed Eddy Current

Pulsed eddy current testing has shown its advantages in the detection of corrosion of insulated pipes and attracted widespread attention. In this study, a pulsed eddy current focusing probe was designed, and its detection ability in complex structural parts was studied through finite element simulation and experiments. The simulation results show that the designed pulse eddy current probe can effectively gather the energy of magnetic field and eddy current field, which is conducive to the detection of local defects and defects in complex structures. By exploring the detection sensitivity of the focusing probe to the pipeline welds and various sizes of local defects under the lift-off of 10 to 50 mm, the detection ability, lift off detection limit and signal characteristics in the detection process were analyzed. The results show that the focusing probe can still detect the square local corrosion defect of 40 mm× 40 mm× 1 mm (length × wide × deep) in size when lifted 50 mm away, and the convex feature of the weld signal and the concave feature of the defect signal are consistent with the simulation results.