Electrical Steel ›› 2025, Vol. 7 ›› Issue (5): 25-.

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Effect of normalization and annealing temperatures on the microstructure, texture evolution and magnetic properties of thin⁃gauge high⁃Si non⁃oriented silicon steels

HUANG Xiaolei,WANG Yinping,LIU Haitao   

  1. State Key Laboratory of Digital Steel,Northeastern University, Shenyang 110819, China
  • Online:2025-10-28 Published:2025-10-21

Abstract: This study focused on a 3.4 %Si non⁃oriented silicon steel. The comprehensive effects of normalization temperature and annealing temperature on the microstructure, texture characteristics, and magnetic properties of the 0.25 mm⁃thick products were studied systematically. The results indicated that normalization treatment at different temperatures could achieve recrystallization and grain growth in the hot⁃rolled sheet, thereby influencing the recrystallized microstructure, texture, and magnetic properties of the final products. With increasing the normalization temperatures, the average grain sizes of the normalized sheets increased obviously, and the microstructure uniformity was improved. In the final annealed sheets, the λ⁃fiber recrystallization texture (<001>∥ND) was notably strengthened, while the γ⁃fiber recrystallization texture (<111>∥ND) was weakened, accompanied by increased grain size. Therefore, with increasing the normalizing temperature, the magnetic induction B50 gradually raised, the low⁃frequency iron loss P1.5/50 gradually decreased, while the high⁃frequency iron loss P1.0/400 first decreased and then increased. In addition, annealing treatment at different temperatures had an important influence on the recrystallization microstructure, texture, and magnetic properties. As the annealing temperature increased, the grain sizes of the final annealed sheets significantly increased, and the λ⁃fiber recrystallization texture was weakened gradually, but the γ⁃fiber recrystallization texture was strengthened progressively. Thus, with increasing the annealing temperature, the magnetic induction B50 initially showed a slight increase followed by a gradual decrease, and the low⁃frequency iron loss P1.5/50 progressively declined, while the high⁃frequency iron loss P1.0/400 first decreased and then gradually raised. An optimal combination of high magnetic induction and low iron loss was obtained at a normalization temperature of 910 ℃ and annealing temperature of 900 ℃, with the following magnetic properties: magnetic induction B50 of 1.70 T, low⁃frequency iron loss P1.5/50 of 2.29 W/kg, and high⁃frequency iron loss P1.0/400 of 13.27 W/kg.

Key words: non?oriented silicon steel, normalization temperature, annealing temperature, microstructure, texture, magnetic properties