Influence of Lüders bands on magnetic Barkhausen noise and magnetic flux leakage signals.

Dhar, A.; Clapham, L.; Atherton, D.

Lüders bands, which occur during the onset of tensile plastic strain in most steels, are localized regions of high plastic strain within a specimen, bounded by regions that have undergone mainly elastic deformation. This study was conducted to understand the dependence of magnetic Barkhausen noise (MBN) and magnetic flux leakage (MFL) signals on Lüders banding in mild steel. MBN and MFL measurements were made on tensile samples of hot-rolled mild steel, in which Lüders bands were deliberately nucleated by applying tensile stress. The results indicate that the MBN activity increases in the region of Lüders bands. A strong magnetic anisotropy was also observed on these bands with the generation of dual magnetic easy axis. The MFL results indicate that magnetic flux leaks out into the air from regions with Lüders bands due to decreasing permeability in these regions owing to localized plastic deformation.

LUDERS bands; BARKHAUSEN effect; MAGNETIC flux; MILD steel; DEFORMATIONS (Mechanics); ELASTICITY

Journal of Materials Science, 2002, Vol 37, Issue 12, p2441

0022-2461

Academic Journal

10.1023/A:1015419018741