Experimental Analysis of Eddy Current Effect Produced during Steel Tube Hi-speed MFL Testing

The high-speed magnetic flux leakage detection system is set up by means of converting the steel pipe linear hi-speed scanning movement into a rotary hi-speed scanning movement. It is identified via analysis that eddy current effect is the root cause for drifting of the baseline. And why eddy current effect exists during the hi-speed MFL detection process is explained from a physical point of view. Also analyzed is the distribution characteristics of the eddy current effect. Relevant comparative analysis shows that 0～12 m/s scanning speed produces little impact on the test signal amplitude value. However,due to the fact that eddy current effect does exist,the baseline of the detection signal waveform is caused to be drifted,and the baseline drifting direction depends on the locations of the magneto sensors mounted in the magnetizer. The trouble of baseline drifting can be fixed by means of some software compensation and adjustment.