Haitao Jiao

Effect of Cold Rolling Process on Microstructure, Texture and Properties of Strip Cast Fe-2.6%Si Steel

The use of twin-roll strip casting for the preparation of non-oriented silicon steel has attracted widespread attention in recent years, but related reports are limited. In this study, both one- and two-stage cold rolling with three intermediate annealing temperatures were employed to produce strip cast non-oriented silicon steel. The evolution of the microstructure and texture through the processing routes and its effect on magnetic properties were studied. Compared with one-stage rolling, two-stage rolling increased the in-grain shear bands and the retention of Cube texture in the cold rolled sheets, thereby promoting the nucleation of favorable Goss and Cube grains and restraining the nucleation of harmful {111}<112> grains. With the increase in intermediate annealing temperature, the η-fiber texture in annealed sheets was gradually enhanced, and the average grain size was increased, leading to significant improvement of magnetic properties.

Effects of hot-rolling reduction on microstructure, texture and magnetic properties of high silicon steel produced by strip casting

Non-oriented Fe-7.1wt.% Si as-cast strips were produced by twin-roll strip casting process. Then the as-cast strips were hot rolled with different reductions, followed by warm rolling and final annealing. The microstructure, texture evolution and magnetic properties were investigated in detail. The texture of hot rolled sheets with 40% reduction showed strongest {001} texture, whereas the dominated texture was turned into {110} and {110} as the reduction was increased to 56% and 68%. After warm rolling and annealing, the average grain size was decreased firstly and then increased with an increase in hot rolling reduction. In the case of 40% hot rolling reduction, the recrystallization texture was dominated by strong γ ( //ND) texture. With an increase in hot rolling reduction, the γ texture was gradually weakened while α ( //RD) texture was enhanced. In addition, relatively stronger {100} texture was presented in the sheet of 68% hot rolling reduction. The highest B50 value attained was 1.66 T and the lowest P10/400 was 24.26 W/kg at a reduction of 56%.

Role of Annealing Time in Thin-Gauge Non-oriented Silicon Steels Processed by Strip Casting

Cold-rolled Fe–2.6%Si sheets of 0.20 thickness prepared by strip casting and two-stage cold rolling were annealed for different time. The microstructure and texture of all samples were investigated by optical microscopy, electron backscattered diffraction and X-ray diffraction to illustrate the effect of annealing time on the development of texture and magnetic properties. The sample in the initial stage of complete recrystallization was characterized by strong η, γ and α component. Goss grains possessed size advantage, and γ grains showed the highest number density. Subsequently, γ-fiber and α-fiber was gradually weakened, whereas η-fiber always predominated the texture. However, with further increase in annealing time, γ-fiber was significantly enhanced and being a dominant component as a result of growth selection of γ grains. Ultimately, the magnetic induction gradually decreased after an increase over time, whereas the core loss displayed a continuous decrease. Texture development with annealing time in the present study could be explained by orientated nucleation mechanism and orientation pinning effect.