Influence of material properties on the detectability of residual stress by Barkhausen noise analysis

The forming quality of sheets is influenced by residual stresses and other material properties. A non-destructive method is required for the quality assurance of sheets. Barkhausen noise analysis as a non-destructive testing technique is used to determine material properties in ferromagnetic sheets. Investigations on the sensitivity of Barkhausen noise analysis for residual stress determination are performed. Tensile tests with different extensions were used to generate different material properties in sheet material of DC 05 (1.0312). Residual stress analysis by X-ray diffraction as well as texture analysis, peak broadening and metallographical inspection were used to characterise the material properties of the specimens. The properties of the Barkhausen noise signal are correlated to these material properties. It is shown, that changes in e.g. hardness have to be taken into account for the determination of residual stress by micromagnetic testing.