Si Non-oriented Electrical Steel Research Articles

Effect of initial grain size on microstructure, texture and magnetic properties of non-oriented electrical steel

The effect of initial grain size prior to cold rolling on the microstructure, texture evolution, and magnetic properties of Fe-3.5 wt% Si non-oriented electrical steel (NOES) was investigated through the introduction of normalization. There were massive intragranular shear bands in {111}<110> and {111}<112> deformed grains in the cold-rolled sheet with large initial grain size, providing nucleation sites for new recrystallized grains with Goss ({110}<001>), λ-fiber, γ-fiber, and {113}<631> components. Subsequent annealing resulted in weaker γ-fiber ({111}<110>−{111}<112>), stronger α*-fiber concentrated at {113}<631>, along with Goss and λ-fiber ({100}<001>−{100}<012>) textures. In addition, appropriate final annealing temperature effectively reduced iron loss. The simultaneous optimization of texture and grain size by normalization and annealing treatments led to improved magnetic properties, with the superior magnetic induction (B50 = 1.719) T, and the lowest core loss (P15/50 = 2.69 W/kg, P10/400 = 16.337 W/kg).

Role of texture before rolling: a research based on texture and magnetic properties of 4.5 wt.% Si non-oriented electrical steel

Role of texture before rolling: a research based on texture and magnetic properties of 4.5 wt.% Si non-oriented electrical steel

Special texture evolution behavior of strip-cast non-oriented electrical steel combined with in-situ experiment and CPFEM

The impact of shear deformation on texture evolution in strip-cast Fe-1.5%Si non-oriented electrical steel was studied combined with in-suit experiments and crystal plasticity finite element method (CPFEM). Throughout the deformation process, the texture evolution predominantly follows a traditional route: transitioning from {211}<036> and {411}<148> to {111}<112> orientation. In certain regions with specific stress conditions, orientation evolution shifts from {310}<236> to {411}<148>, {100}<021>, and finally to {100}<001> orientation. Crystal plasticity finite element (CPFE) simulation results show that the rotation of {310}<236> through {411}<148> to {100}<021> orientation, {211}<236> and {112}<110> orientations transition to {111} and {110} orientations, respectively, which is consistent with the experimental observations. Recrystallization texture mainly includes favorable λ and near-λ (<100>∥ND, normal direction) textures, with detrimental γ (<111>∥ND) texture essentially diminishing. In-situ heating experiments revealed {411}<148> as the primary recrystallization orientation, the mechanism involves both oriented nucleation and growth. In the edge region lacking stress constraints, the Schmid factor (SF) reaches up to 0.48, the (21-3)[111] slip system is preferentially activated, with shear bands appearing earlier in the same region. Indicating that when slip mechanism alone are inadequate for sustaining plastic deformation, the shear deformation becomes the favored mode of activation. {411}<148> orientation can serve as a transitional orientation for transitioning to {100} orientation, and further as an advantageous transitional orientation during the nucleation and growth of recrystallization. Due to the texture improvement, superior magnetic properties were achieved, with the average magnetic induction (B50) and iron loss (P1.5/50) being 1.77 T and 4.25 W/kg, respectively.

The Growth of {1 1 h}〈1 2 1/h〉 (α*-Fiber) Grains and the Evanesce of {001}〈100〉 (Cube) Grains During the Recrystallization of Warm Rolled Fe-6.5 Wt Pct Si Non-oriented Electrical Steel

The Growth of {1 1 h}〈1 2 1/h〉 (α*-Fiber) Grains and the Evanesce of {001}〈100〉 (Cube) Grains During the Recrystallization of Warm Rolled Fe-6.5 Wt Pct Si Non-oriented Electrical Steel

Effect of Superheat on the Initial Solidification Behaviors of 3.5 wt pct Si Non-oriented Electrical Steel During Strip Casting

Effect of Superheat on the Initial Solidification Behaviors of 3.5 wt pct Si Non-oriented Electrical Steel During Strip Casting

Effect of Annealing Temperature and Time on the Magnetic Properties and Magnetic Anisotropy of a Temper-Rolled, Semi-processed Non-oriented Electrical Steel

The effect of final annealing temperature and time on the core loss, magnetic permeability, and magnetic anisotropy of a temper-rolled, semi-processed 0.5 wt.% Si non-oriented electrical steel was investigated. The magnetic properties of the steel sheets at 50–400 Hz and 0.5–1.50 T were measured by the Epstein frame method on strips cut along both the rolling (RD) and transverse directions (TD). Optimal magnetic properties were obtained when the annealing temperature was at 800–825°C, and the annealing time was 2–4 h. Relatively large magnetic anisotropy between the RD and TD was observed in samples after recrystallization (~ 10% in core loss and ~ 70% in relative permeability), while deformed and non-recrystallized samples showed small anisotropy in magnetic properties. Regardless of the processing state of the steel, i.e., temper-rolled, recovered, or recrystallized, the core loss followed quadratic polynomial functions with respect to both the frequency and magnetic flux density, while the relative magnetic permeability followed cubic polynomial functions with respect to both the frequency and magnetic flux density. The microstructure and texture of selected samples were characterized by electron backscatter diffraction, which revealed the correlations between the magnetic properties of the steel and the microstructure and texture.

A comprehensive study on texture evolution and recrystallization mechanism of Fe-4.5 wt% Si with strong {114}

Improving both the magnetic properties and strength of non-oriented electrical steel used in driving motors of new energy vehicles is a great challenge. In this study, a 4.5 wt% Si non-oriented electrical steel that had a strong {114}<481> texture and exhibited excellent magnetic and high strength, was produced via hot rolling, cold rolling and annealing. The texture evolution of hot-rolled plate with strong Goss and medium strength λ-fiber ({100}<0vw>) was investigated in detail during rolling and annealing. The VPSC model was used to simulate the texture evolution during the rolling process, of which the neff model could satisfactorily explain the classical rotation route of Goss and Cube. At the initial stage of recrystallization, the orientation of the recrystallized grains, characterized by electron backscatter diffraction (EBSD), was closely related to the orientation of the hot-rolled plate and rotation path during the rolling process. This clear evidence indicated that the initial recrystallized grains were oriented nucleation. During the recrystallization process, the characterization of specific orientations by quasi-in-situ EBSD revealed that the unusual {114}<481> was formed by an oriented growth mechanism. Texture evolution during the recrystallization indicated oriented nucleation as an inherent property responsible for the initial recrystallization texture, while oriented growth was influenced by deformed grain size and grain boundary characteristics.

Effect of Annealing Time on Texture Evolution of Fe–3.4 wt% Si Nonoriented Electrical Steel

Herein, the effect of annealing time on the texture evolution in Fe–3.4 wt% Si non‐oriented electrical steel is investigated. Strip samples are cast using a vacuum sampling method, which simulate the solidification conditions of an industrial twin roll thin strip casting (TRSC) process. As‐cast samples with different carbon and sulfur (C&amp;S) levels are hot rolled (HR) with varying levels of hot deformation, cold rolled (CR) to 0.35 mm thickness, and then annealed at 1050 °C for different holding times (1, 6, 24 h). To Fe–3.4 wt% Si nonoriented electrical steel, the observed texture evolution can be divided into different stages as annealing time is increased from 1 to 24 h. With increasing annealing time, the fraction of Goss texture decreases initially and then increases again through the consumption of grains with other textures. With additional time, a decrease of pinning force due to precipitate coarsening results in normal grain growth, resulting in an increase of grain size. In this step, Cube grains can form from rotated Goss grains. A model for core loss is presented and used to explain the core loss results.

Effects of slab reheating temperature and hot rolling process on microstructure, texture and magnetic properties of 0.4% Si non-oriented electrical steel

The effect of different slab reheating temperatures (1150 °C and 1000 °C), thicknesses of hot rolled sheet (2.8 mm, 2.3 mm and 2.0 mm) and coiling temperatures (630 °C and 750 °C) on microstructure, texture and magnetic properties of 0.4 wt% Si non-oriented electrical steel was comparatively studied in detail. This work focused on the effect of ultra-low temperature slab reheating and ultra-thin gauge hot rolling on magnetic properties. It was found that with the thinning of hot-rolled sheet thickness, the final grain size increased and iron loss decreased regardless of slab reheating temperature and coiling temperature. Lowering slab reheating temperature or increasing coiling temperature could further reduce iron loss. However, their effect on magnetic induction was relatively complex. When coiling at low temperature of 630 °C after hot rolling, decreasing thickness of hot rolled sheet did not always improve magnetic induction, but also depended on the reheating temperature. Because the low coiling temperature could not eliminate severely deformed grains in hot rolled sheets, which obviously deteriorated magnetic induction. To eliminate the deformed grains, coiling temperature was increased from 630 °C to 750 °C, and the microstructures were fully equiaxed grains. Both thinning hot-rolled sheet thickness and lowering slab reheating temperature promoted the development of shear bands during cold rolling, thus resulting in weakening γ-fiber (<111>//ND) texture and strengthening λ-fiber (<100 >//ND) in final sheets. As a result, the magnetic induction was significantly increased. Furthermore, the recrystallization behavior of different cold rolled microstructures during annealing was investigated using a quasi-in-situ electron backscattered diffraction (EBSD) technique.

The effect of temper rolling and final annealing on microstructure, texture and magnetic properties of non-oriented electrical steels

In this paper, the effect of temper rolling and final annealing on microstructure, texture and magnetic properties of a 0.6 wt% Si non-oriented electrical steel, with 5.7% temper rolling reduction, were investigated via EBSD and XRD three-dimensional orientation distribution function (ODF) analysis. The results indicate that final annealing plays an essential role in improving the magnetic properties of non-oriented electrical steels. The core loss decreases with the increasing annealing time, reaches the lowest value at 10 min, and then tends to be stable. The magnetic induction quickly increased with prolonged annealing time, reached the highest value, then decreased slightly to a lower value after 15 min. The peak permeability increased rapidly with the increasing annealing time, reached the highest value after 3 min, and became stable after 10 min. The grains abnormally develop from the sample surface to the inner layer derived from gradient strain. Before and after temper rolling, the texture of the material is mainly dominated by {111}<112>. As annealing time increases, the intensity of {111}<112> decreases, emerging the weak Goss ({110}<001>) and other orientations. Finally, there are without preferred orientations when time exceeds 10 min.

Effect of rolling process on magnetic properties of Fe-3.3 wt% Si non-oriented electrical steel

Effect of rolling process on magnetic properties of Fe-3.3 wt% Si non-oriented electrical steel

High-temperature oxidation mechanism of Fe-3.0 wt%Si electrical steel with hybrid atmosphere

The oxidation behaviors of Fe-3.0 wt%Si non-oriented electrical steel were studied in the high-purity Ar, compressed dry air, Ar-H 2 O mixed, and Air-H 2 O mixed atmosphere when annealed at 1200 °C for 200 min. The oxide layers generation and transformation mechanism of electrical steel during the high-temperature annealed process was characterized and discussed systematically by means of the XRD, SEM, EDS, and XPS analysis methods. Under compressed air conditions, only O 2 participates in the oxidation reaction. And the oxide layer has a typical three-layer structure. The oxidized particle layer only could be observed in the H 2 O-containing atmosphere, and the particle size and morphology of the oxide layer present an obviously evolution process. During the oxidation reactive process between Fe, Si and O, H 2 O and O 2 could play a synergistic effect. In addition, this synergistic effect leads to the cross-wrap structure appearing between the oxidized particle layer and the outermost oxide layer. The oxide layer thickness increases significantly in the Air-H 2 O atmosphere because of above conditions. This research lays the groundwork for a more in-depth investigation of silicon steel oxidation behavior. • Annealed with the hybrid atmosphere was applied to study the oxidation mechanism of Fe-3.0 wt%Si electrical steel. • The synergistic effect of H 2 O and O 2 leads to the cross-wrap structure appearing between the oxidized particle layer and the outermost oxide layer.

Effect of Cooling Rate on Magnetic Properties of Fe-3.3 wt% Si Non-oriented Electrical Steel

Effect of Cooling Rate on Magnetic Properties of Fe-3.3 wt% Si Non-oriented Electrical Steel

Texture Adjustment of Hot-Rolled Fe-1.6 wt% Si Non-oriented Electrical Steel Sheet by Annealing Processes

Texture Adjustment of Hot-Rolled Fe-1.6 wt% Si Non-oriented Electrical Steel Sheet by Annealing Processes

Oxide Scales on Commercial Hot Rolled 1.5%Si Non-oriented Electrical Steel and the Pickling Behaviors

Oxide Scales on Commercial Hot Rolled 1.5%Si Non-oriented Electrical Steel and the Pickling Behaviors

Mechanical properties and crystallographic texture of non-oriented electrical steel processed by repetitive bending under tension

Improving the magnetic properties of non-oriented electrical steel (NOES) through the optimization of crystallographic texture has been an on-going research activity for decades. However, using traditional rolling and annealing procedures, the obtained final textures were usually very similar, i.e., exhibiting the {111} (γ) and <110> (α) fibres, which were not the desired {001} texture (θ-fibre) for optimal magnetic quality. In the current work, a 1.8 wt% Si NOES was processed using a new sheet metal deformation method, i.e., repetitive bending under tension (R-BUT), also known as continuous bending under tension (C-BUT), to modify the texture of the electrical steel. The hot-rolled and annealed NOES plates were repeatedly bent and unbent when they were pulled under tension. The deformed plates were then heat treated at different temperatures for various times. Neutron diffraction and electron backscatter diffraction (EBSD) characterisation of the macro- and micro-textures proved that the R-BUT process significantly reduced the undesired {111} texture while promoting the {001} texture. The cube texture, which rarely formed after conventional rolling and annealing, was also seen in the R-BUT samples after annealing. It was shown that, the shear plastic deformation (induced by R-BUT) played a significant role in promoting the desired textures. In addition, the results indicated that the NOES processed by R-BUT could be deformed beyond its common formability limit, which may provide a method to address the poor workability challenge of high silicon electrical steels.

Effect of rolling temperature on the recrystallization behavior of 4.5 wt.% Si non-oriented electrical steel

A 4.5 wt.% Si non-oriented electrical steel with a thickness of 0.50 mm was prepared following a conventional process route. Due to the insufficient formability of high-Si steels, this study focuses on the effect of warm rolling temperature on the evolution of microstructure and texture in the hot-rolled sheet after appropriately selected annealing process. The optical microscope (OM) and field emission scanning electron microscope (SEM) with EBSD equipment were utilized to characterize the microstructure evolution during the fabrication process. The results show that the warm rolling temperature significantly impacts the evolution of the microstructure and texture of the 4.5 wt.% Si steel. When rolling at a lower temperature, shear bands appeared within the plate. The shear band vanished as the rolling temperature increased, and obvious delamination can be observed. When further increasing the temperature, the dynamic recrystallization occurred on the surface layer of the plate. The increase of the warm rolling temperature reduced the average grain size after final annealing, and the structural delamination was more obvious. The microstructural characteristics of the warm-rolled sheet affect the subsequent evolution of the texture. Affected by shear bands and delamination, different warm-rolled sheets have different recrystallization textures after final annealing.

Texture Evolution during Recrystallization and Grain Growth in Non-Oriented Electrical Steel Produced by Compact Strip Production Process.

Evolution of texture and α*-fiber texture formation mechanism of Fe-0.65%Si non-oriented electrical steel produced by Compact Strip Production (CSP) process during all the thermo-mechanical processing steps were investigated using electron backscatter diffraction (EBSD) and X-ray diffraction (XRD) techniques. Columnar crystal structure of cast slab is fine and well-developed. Textures of the hot-rolled band are quite different in the thickness direction. During annealing of cold-rolled sheet, γ-fiber texture grains would nucleate and grow preferentially, and α*-fiber texture grains mainly nucleate and grow in the shear zone of α-fiber texture of cold-rolled sheet. During the recrystallization process, γ-fiber texture gradually concentrated to {111}<112>, and γ and α*-fiber texture increased significantly. {111}<112> texture priority nucleation at the initial stage of recrystallization. Due to the advantages of nucleation position and quantity, the content of α*-fiber texture is greater than {111}<112> texture in the mid-recrystallization. During grain growth process, {111}<112> oriented grains would grow selectively by virtue of higher mobility, sizes and quantity advantages than that of {411}<148 > and {100}<120>, resulting in the gradual increase of γ-fiber texture and the decline of α *-fiber texture.

Optimum Magnetic Properties of Non-Oriented Electrical Steel Produced by Compact Strip Production Process

Optimum grain size and effects of crystallographic textures on magnetic properties of Fe-0.65%Si non-oriented electrical steel produced by compact strip production (CSP) process were investigated by optical microscope, electron backscatter diffraction (EBSD), and X-ray diffraction (XRD) techniques. Magnetic induction and core loss show a decreasing trend with the increase of grain size, and grain sizes for optimal magnetic properties are in the range of 26–30 μm. Core loss would be mainly affected by grain size, whereas crystallographic texture would primarily affect magnetic flux density. Magnetic properties increase with increasing of texture factor (volume fraction ratio of {100}/{111}) and magnetic texture factor (volume fraction ratio of &lt;100&gt;/&lt;111&gt;), and increasing with the decrease of A-parameter (minimum angle between magnetization direction and the closest &lt;100&gt; direction) and A(h→), respectively. Simultaneously, with increasing of A-parameter and A(h→), a linear decrease of B50 was obtained.

Dynamic recrystallization behavior and texture evolution of as-cast Fe-4.53%Si non-oriented electrical steel during hot compression

The dynamic recrystallization behavior and texture evolution of surface, quarter and center layers of as-cast Fe-4.53%Si non-oriented electrical steel during hot compression were studied by optical microscope and electron backscatter diffraction. The surface layer of cast ingot exhibited elongated columnar grains with pronounced {001}&lt;130&gt; and {001}&lt;120&gt; textures, while the quarter and center layers of ingot were mainly large equiaxed grains corresponding to strong {100}&lt;0vw&gt; texture. During hot compression, the shear bands were easy to form in the deformed grains with higher stored energy such as {110}&lt;001&gt;, {014}&lt;114&gt; and {312}&lt;332&gt; grains which is conducive to promoting recrystallization. Due to that the shear band was not easy to form in the {100}&lt;0vw&gt; grain with lower stored energy, the large grains corresponding to strong {100}&lt;0vw&gt; texture in the quarter and center layers of ingot undergone obvious deformation and slight orientation transformation during hot compression process which proved the good heritability of as-cast {100} texture.