The Application of Magnetic Shielding Effect in Drill Pipe Magnetic Leakage Flux Testing

Electromagnetic finite element analysis shows that pipe magnetic flux leakage signals are centralized near defects obviously when the magnetic shielding exists. At this time, the background magnetic flux between permanent magnet components coupling through the air medium will be reduced greatly. Drill pipe magnetic flux leakage testing confirms the analysis results, and the probe with magnetic shielding device can improve SNR of the magnetic flux leakage signals obviously. Thus, it is helpful to improve pipe leakage flux testing sensitivity.