Recrystallization Behavior of Hot‐Rolled Microstructure with Texture Gradient and Texture of Final Sheet in Thin‐Gauge Electrical Steel

Abstract

The typical feature of hot‐rolled sheets exhibits strong inhomogeneity in microstructure and texture along the thickness direction, and the latter can be named as texture gradient. Herein, the recrystallization and grain growth behaviors of the hot‐rolled sheet in a thin‐gauge nonoriented electrical steel are investigated at different normalization temperatures. The origin and the growth behavior of the main recrystallization texture {114}<481> are revealed. The results show that the texture gradient in hot‐rolled sheets leads to the difference in microstructure and texture between the surface layer and the central layer after normalization. The strong {114}<481> recrystallization texture originates in the orientation transition zone and the vicinity of the grain boundaries of deformed α‐fiber grains in the central layer of hot‐rolled sheets. The volume advantage of {114}<481> grains stem from the favorable growth environment caused by the low‐deformation stored energy, low orientation gradient, higher mobility of grain boundary, and size advantage to their surrounding deformation structure. In the final sheet, {100}<021> texture is the most vital texture, but {114}<481> grains exhibit a large volume fraction. As there are only 4–5 grains on average along the thickness direction of the final sheet, the texture gradient along the thickness direction no longer exists.

On the Metastable Ferrite Hot Rolling of Low‐Grade Electrical Steels: Its Microstructure, Texture and Low‐Temperature Annealed Structure

“…Therefore, the corresponding texture is weakened without significant changes, and it is also obviously different from the typical {114}<481> texture that appears at high‐temperature normalization annealing. [ 20 ] Furthermore, the uneven hot rolling process results in a significant microstructure disparity between the surface layer and the central layer. Consequently, during low‐temperature annealing and recrystallization, a substantial size discrepancy arises, forming a small number of near {100} grains larger than 100 μm.…”

“…In a separate work, we carried out the experiment of heating and rolling the continuous casting slab directly at 900 and 1100 °C held for 10 min, and confirmed that the coarse and deformed ferrite could be obtained. [ 20 ] The described methodology and analysis provide valuable insights into the microstructure evolution during the industrial production of low‐grade electrical steels. The proposed approach of heating the columnar‐grained slab at 900 °C for 20 min, followed by further heating to 1100 °C for a holding time of 10–20 min before hot rolling, allows for a detailed examination of the structural changes.…”