Complete Goss Secondary Recrystallization by Control of the Grain Size and Texture of Primary Recrystallization in Grain-Oriented Silicon Steel

Abstract

Matrix microstructure and texture controlling is an important way to optimize Goss ({110}<001>) abnormal grain growth (AGG) in high magnetic induction grain-oriented silicon (Hi-B) steel during primary recrystallization. In the present work, a matrix with homogeneous grain size and favorable texture components was obtained through two-stage normalized annealing followed by primary recrystallization. Furthermore, secondary recrystallization was performed for sharp Goss orientation by slow heating and purified annealing. It was found that plenty of island grains, which occurred and disappeared gradually, accompanied the process of AGG. Through analyzing the evolution of microstructure and texture, we realized that the formation of island grains was related to the large-size grains in matrix, and the elimination of that was attributed to the special grain boundaries which satisfied both coincident site lattice (CSL) and high-energy (HE) models. It was essential to control grain size and favorable orientations in matrix comprehensively for the high-efficient abnormal growing of sharp Goss orientation, through which excellent magnetic properties could be obtained simultaneously.

Phase-Field Simulation on the Effect of Second-Phase Particles on Abnormal Growth of Goss Grains in Fe-3%Si Steels

“…A detailed observation to capture the formation process of island grains is shown in Figure 15 . The simulated results and experimental observations are consistent in finding two types of island grains [ 49 ]. As it shows that Goss grains could wrap around these grains and cause island grains to appear.…”

“… The formation process of island grains in: ( a – f ) simulated results, ( g , h ) experimental observations [ 49 ]. A2 is the isolated island grain, D3 is the serial island grain in the simulated results.…”

Effect of Gradient Heat Conduction on Secondary Recrystallization of Grain-Oriented Silicon Steel

“…The development of secondary recrystallization has a great impact on the magnetic properties of grain-oriented silicon steel. Many studies [1][2][3][4][5][6][7] have been conducted on the related factors affecting secondary recrystallization, including key element content, precipitate, primary recrystallization structure, high-temperature annealing process, etc.…”

“…Three main theories have been developed so far on the mechanism of secondary recrystallization of grain-oriented silicon steel [17][18][19]. (1) Coincident site lattice boundaries theory: The probability of the occurrence of movable coincident site lattice boundaries between the Goss-oriented primary grains and the surrounding grains is the highest.…”

Research on Secondary Recrystallization Mechanism of Oriented Silicon Steel

“…However, the main point in common between the two theories is that some special GB types are easily formed around Goss grains (such as ∑3-9 in the CSL model and 15-45 • disorientation in the HE model), and the particles can easily dissolve at those particular types of GBs, resulting in a strain or even a disappearance of the pinning effect [15]. Northeastern University describes the kinetic process of secondary recrystallization of oriented silicon steel utilizing grain boundary energy [16] and concludes that orientation selection behavior results from the multi-factor coupling. The above studies…”