Effect of laser scribing on the residual stress formation in Fe-Si electrical sheets: Numerical and experimental evaluation

Electrical steels are widely used in the manufacturing of transformers in the energy sector. Improving their efficiency leads to an immediate saving of electrical energy in transformer operations. Laser scribing is an established laser treatment technology to reduce losses in highly permeable grain-oriented electrical steel sheets. This process creates residual stresses in the material through non-uniform plastic deformation of the sheets, which influence the formation of the magnetic domains. However, this effect is not fully understood. In this study, we use numerical and experimental tools to enhance our understanding of the residual stress formations during the laser scribing process. The effect of different process parameters and designs have been studied by developing a three dimensional thermo-mechanical model, which was validated by diffraction-based experiments. The results create a clear picture of the residual stress distribution around the laser lines, which improves our understanding of their effects on the observed magnetic fields.