Study on the Impact of Magnetic Flux Leakage Probe Lift-off on the Detection Signals

Probe lift-off is the most important factor to affect the result of magnetic flux leakage (MFL) detection. To analyze the influence, the acquisition system of lift-off signals is constituted, the testing signals are acquired in different lift-off conditions, the influence of probe lift-off to the defect signals is analyzed, the viewpoint such as "lift-off sensitive area", lift-off threshold, the best lift-off value are proposed. The method can be used to optimize the probe construction and tutor the design of testing system.