Effect of laser line interruption on the structure and magnetic properties of GO-silicon-steel-sheets in the laser scribing process

In this work, the effect of laser line interruption was studied on the structure and magnetic properties of grain-oriented silicon steel sheets during the laser-scribing process in the presence/absence of an external magnetic field. By applying different patterns of interruption, the effect of discontinuity length, one-sided or two-sided application of laser and overlapping or non-overlapping of laser lines (for sheets scribed on both sides) was investigated on the domain structure and core losses of silicon steel sheets. Based on the results of these experiments, the optimal conditions of discontinuous laser scribing were obtained. The results show that although at small interruption lengths such as 2 mm, the effect of laser scribing is negligible on reducing the core losses, but by increasing the interruption length to about 6 mm, the magnetic losses are greatly improved. By re-increasing the length of interruption to about 10 mm, the core losses increase again and this indicates that a break length of 6 mm creates optimal core losses in the sheets. Use of a longitudinal external magnetic field during the discontinuous laser irradiation with an optimum interruption pattern results in a reduction of about 16% in core losses in grain-oriented silicon steel sheets.