An accurate evaluation of the residual stress of welded electrical steels with magnetic Barkhausen noise

• Residual stress in welded steels was accurately determined by the Barkhausen noise.
• Deviation between MBN and XRD in stress evaluation was within acceptable limits.
• The results were verified by microstructural and mechanical characterization.
• Stress was in-situ monitored and correlated to MBN values by a calibration curve.
• The results imply possible applicability of MBN in NDT of various welded steels.

In the present research work the determination of residual stress distribution in welded non-oriented electrical steel samples is discussed. Tungsten Inert Gas, Plasma and Electron Beam were used as the welding methods. Residual stress was directly determined through deformation measurements and appropriate math calculations. Two methods were used: The magnetic, non-destructive method of Barkhausen noise and the semi-destructive method of X-ray diffraction. In order to evaluate accuracy and reliability of the magnetic method applied, the steel samples were subjected in both compressive and tensile stresses and the magnetic noise values were correlated to residual stress values through an appropriate calibration curve. The results were then verified by the XRD method. Then, these were further evaluated by examining the microstructure and mechanical properties of as received and welded samples by scanning electron microscopy and macrohardness measurements, respectively. It was found that the deviation between the two methods was within acceptable limits, thus implying potential applicability of the MBN method in non-destructive testing of materials.