Magnetic anisotropy of plastically deformed low-carbon steel

Macroscopic hysteresis and local Barkhausen noise techniques were used for the comprehensive magnetic investigation of structural low-carbon steel subjected to uniaxial plastic tension. Scattering of the measured magnetic parameters was substantial within the Lüders band region with stabilization at higher strains. Compressive residual stresses in the deformation direction formed a hard magnetization axis with intriguing two-phase remagnetization. The magnetic parameters had the highest sensitivity to strain in this direction. They changed as cos² with rotation to the perpendicular easy magnetization axis, where the magnetic sensitivity was the lowest. The relation between the deformed steel microstructure (dislocation and residual stress patterns) and the obtained magnetic behaviour is interpreted. The applicability of the examined techniques for the non-destructive characterization of steel degradation is discussed.