Evolution of {0kl} ⟨1 0 0⟩ texture and microstructure in preparation of ultra-thin grain-oriented silicon steel

In this paper, an ultra-thin grain-oriented silicon steel (UTGO steel) strip was prepared via rolling a commercial glassless grain-oriented silicon steel plate to 0.075 mm and then annealing it at 850 degrees C for less than 30 min in a protective atmosphere. The resultant UTGO steel strip has magnetic induction B-800 higher than 1.80 T and iron loss P-1.5/400 lower than 12.0 W/kg. These superior magnetic properties are due to predominant {0kl} < 1 0 0 > texture and appropriate microstructure. The study shows that preferential {0kl} < 1 0 0 > nucleation occurs either inside shear bands or at in-grain deformation-induced boundaries. The nucleation behavior varies at different nucleation sites. Nuclei inside shear bands are denser and show preferential transitional orientation along {0kl} < 1 0 0 >, while new grains dispersed at in-grain split boundaries have shown orientations which are suggested to inherit corresponding initial grain orientation prior to rolling. Nucleation behavior is also highly dependent on the orientation of the roll-deformed matrix. Our study finds that shear banding nucleation of {0kl} < 1 0 0 > (including Goss and {0 2 1} < 1 0 0 >) is reduced when the orientation of the deformed matrix deviates from {1 1 1} < 1 1 2 >. With the extension of annealing time, the growth of {0kl} < 1 0 0 > nuclei in cluster is restricted because of orientation pinning effect, whereas the growth of grains with orientations other than {0kl} < 1 0 0 > is promoted. This phenomenon weakens the dominance of {0kl} < 1 0 0 > texture, causing deterioration in magnetic properties of the final silicon steel.

Automated summary

In this study, an ultra-thin grain-oriented silicon steel strip with superior magnetic properties was prepared through rolling and annealing processes. The nucleation behavior of different orientations inside the steel strip significantly affected its final magnetic properties. The dominance of specific texture and structure in the steel strip played a crucial role in determining its magnetic properties.