Non-destructive Flaw Mapping of Steel Surfaces by the Continuous Magnetic Barkhausen Noise Method: Detection of Plastic Deformation

This paper reports the use of a non-destructive scanning technique to identify plastic deformation defects generated in steel. The technique is based on measurement of continuous magnetic Barkhausen noise (CMBN). In the experiments described here, surfaces with plastic deformations produced by crushing stresses in a 1070 steel are scanned, and the influence of probe configuration, coil type, scanner speed, applied magnetic field and the frequency band used for the analysis on the effectiveness of the technique is studied. A moving smoothing window based on a second order statistical moment is used to analyze the time signal. The results show that the method can detect the position of plastic deformation defects and distinguish between their amplitudes.