Abstract
•An UTGO Steel with superior magnetic properties was prepared with glassless GO Steel.•Elaborated nucleation characteristics of {0kl} 〈1 0 0〉 oriented recrystallized grains.•Systematically discussed {0kl} 〈1 0 0〉 orientation evolution and influencing factors.
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 °C for less than 30 min in a protective atmosphere. The resultant UTGO steel strip has magnetic induction B800 higher than 1.80 T and iron loss P1.5/400 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.