Pipeline External Defect Detection Based on Magnetically Focused Eddy Current Testing System

Eddy current internal inspection technology has been extensively studied and applied in industrial environments such as oil and gas pipelines. Typically, the penetration depth of eddy current testing in ferromagnetic pipes is reduced compared to non-ferromagnetic materials due to their high magnetic permeability. Given the presence of noise interference in eddy current testing systems, enhancing the signal quality of receiver coils constitutes a critical research focus. This paper proposes and validates through simulations a non-contact magnetically focused eddy current testing (MFECT) system for pipeline internal inspection. The system effectively enhances the signal-to-noise ratio of the receiver coils, mitigates the skin effect, and increases the penetration depth. Comparative analyses of penetration depth with and without magnetic focusing were conducted. Furthermore, the optimal operating frequency of the excitation signal was determined through simulation studies. Finally, the feasibility of the proposed method was verified through experiments.