Primary Recrystallization Texture Research Articles

Influence of Fine Precipitates on Primary Recrystallization Mechanism and Texture Formation in Cold Rolled Fe-3%Si Alloy with Initial Coarse Goss Grains

Influence of Fine Precipitates on Primary Recrystallization Mechanism and Texture Formation in Cold Rolled Fe-3%Si Alloy with Initial Coarse Goss Grains

Coordinate regulation mechanism of primary recrystallization texture and microstructure of grain-oriented silicon steel

Texture control, which is affected by composition, hot rolling, cold rolling, and annealing, is the core element to improve the magnetic properties of grain-oriented silicon steel and is one of the key scientific problems in developing electrical steel technology. The research and control of first factors have been very mature, and the integrated regulation of upstream and downstream processes has become a breakthrough point for improving texture. For the common grain-oriented silicon steel based on the “two-stage cold rolling method”, primary recrystallization is the stage achievement of smelting, hot rolling, first cold rolling, and decarburization annealing. The grain size and texture characteristics of the primary recrystallization are the only standards to measure the pre-process technology and is the pointer of whether the secondary recrystallization can occur in the subsequent process or not, which are extremely important to improve the magnetic properties. This paper studied the hot rolling, the first cold rolling and decarburization annealing of grain-oriented silicon steel by using XRD, EBSD technologies. The results showed that the hot rolled plate is not as thinner as better, only the optimum ratio of the thickness of hot rolled plate and the first cold reduction rate can obtain optimal primary recrystallization. The minimum iron loss value and maximum magnetic induction intensity are obtained under the primary cold rolling reduction rate controlled at 77.27%, the average grain size of the primary recrystallization is 14 µm, the iron loss P1.7/50 is reduced to 1.02 W/Kg, and the magnetic induction intensity B8 can reach 1.910 T.

Investigation of microstructure and texture as related to primary recrystallization of grain-oriented silicon steel

Grain-oriented silicon steel requires a very strong Goss {110}<001> texture and as such a comprehensive control of thermo-mechanical processing parameters is required to achieve a strict control of texture. In particular the cold rolling and decarburization annealing process parameters have a determining effect on the grain size, the grain size distribution and the crystal texture distribution. In this study, the effect of cold rolling reduction on texture distribution in cold-rolled sheet has been analyzed. Secondary recrystallization of grain-oriented silicon steel is also highly dependent on the microstructure and texture after primary recrystallization. The influence of annealing temperature and carbides on the primary recrystallization process has also been investigated by measurements of grain growth and texture following primary recrystallization. By optimizing the microstructure and the texture of primary recrystallization of grain-oriented silicon steel, it is shown that a grain-oriented silicon steel exhibiting high magnetic induction low iron loss has been developed at Shougang Steel.

Influence of Fine Precipitates on Primary Recrystallization Mechanism and Texture Formation in Cold Rolled Fe-3%Si Alloy with Initial Coarse Goss Grains

Influence of Fine Precipitates on Primary Recrystallization Mechanism and Texture Formation in Cold Rolled Fe-3%Si Alloy with Initial Coarse Goss Grains

Secondary recrystallization of Goss texture in one-stage cold rolled Fe–Ga thin sheets via a large rolling reduction

Preparing Fe–Ga sheets with excellent magnetostrictive coefficients by rolling and annealing methods can greatly promote the development of high-efficiency magnetostrictive devices. 0.3 mm thick Fe–Ga thin sheet was produced by the one-stage large-reduction cold rolling method without intermediate annealing. Trace V and Nb elements addition improves the rolling formability of the Fe–Ga sheet by precipitating a large number of (Nb,V)C particles. The evolution of precipitation, microstructure, texture, and magnetostrictive coefficients in the Fe–Ga sheet was investigated. The microstructure of primary recrystallization is composed of homogenous distribution of fine grains with an average grain size of about 22 μm. The composite inhibitors composed of MnS and (Nb,V)C precipitates with a particle size of 40∼80 nm suppress the matrix grains effectively. The primary recrystallization texture consists of a strong γ texture with a peak at {111}&amp;lt;112&amp;gt; and a relatively strong {114}&amp;lt;481&amp;gt; texture. The secondary recrystallization of Goss grain occurs at the annealing temperature of 900 °C and is completed at 1100 °C by the combined effects of the existing inhibitor and texture. The Fe–Ga thin sheets composed of several millimeter-sized grains of Goss texture accompanied by small grains oriented by {114}&amp;lt;481&amp;gt; were obtained after annealing at 1100 °C, and its measured magnetostriction value is about 238 ppm. The present work proposes a promising routine to produce high-performance Fe–Ga thin sheets.

Secondary Recrystallization Texture and Magnetostriction in Fe-Ga Alloy Ultra-Thin Sheet

The 0.15 mm thick Fe-Ga alloy ultra-thin thin sheets with high magnetostriction were successfully produced by the conventional processing route including hot rolling and two-stage cold rolling with intermediate annealing and primary and secondary recrystallization annealing. The evolution of microstructure, texture, and inhibitor was briefly investigated. The primary recrystallization texture is characterized by strong <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\gamma $ </tex-math></inline-formula> fiber with the peak at {111} <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\langle 112\rangle $ </tex-math></inline-formula> component and weak Goss component through sheet thickness. The dispersedly distributed nano-precipitates provide a sufficient pinning effect on the primarily recrystallized grains and induce abnormal grain growth of Goss grains. Well-developed secondary recrystallized Goss grains with centimeter size and maximum magnetostriction (3/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\lambda \text{s}$ </tex-math></inline-formula> ) of 229 ppm were achieved in Fe-Ga alloy ultra-thin sheet.

Effects of primary recrystallization texture and inhibitor characteristic on the secondary recrystallization of Fe-Ga alloy thin sheet induced by nano-sized inhibitor

Sharp Goss texture and excellent magnetostriction coefficient were successfully developed in Fe–Ga alloy thin sheet by composite nano-sized inhibitor. Various primary recrystallization textures in Fe–Ga alloy thin sheets were produced by different cold rolling reductions. The effect of primary recrystallization texture and inhibitor characteristics on the secondary recrystallization of Fe-Ga alloy thin sheet was investigated. The results show that the nano-sized sulfide provides a sufficient pinning force to the normal grain growth of primary grains. The increase in size and distribution width of precipitation during high-temperature annealing indicates the preferentially weakened pinning force. Goss grains in the primary recrystallization do not predominate in number and grain size, but it is surrounded by a higher fraction of high energy grain boundaries (HEGBs). Complete secondary recrystallization of Goss grains can be induced by the preferentially weakened inhibitor and the priority of grain boundary energy and mobility around Goss grains. The cold-rolling reductions have a significant influence on the secondary recrystallization by changing the primary recrystallization texture and the grain boundary characteristics. Based on the relationship between the anisotropic grain boundary energy and mobility and the misorientation angle, a multi-parameter interaction model is proposed to explain the nucleation and development of secondary recrystallization Goss texture under the pinning force.

Crystallographic texture of tape substrates for HTSC from Cu-40%Ni alloy with additives of refractory elements

The texture of deformation and primary recrystallization in copper-nickel alloys with the addition of a small amount of refractory elements such as Nb, Mo, Ta and W was studied. Based on the X-ray analysis of the deformation texture using the orientation distribution function, it was shown that the volume fraction of the C and S components in alloys is greater than the double volume fraction of the unfavorable component B. In accordance with this criterion, after primary recrystallization in all the studied alloys, a sharp cubic texture {100}< 001 > was obtained with a volume fraction in the± 10° region of more than 95%. Alloying with refractory elements significantly increases the strength of the base copper-nickel alloy by the mechanism of solid-solution hardening. The evaluation of the mechanical characteristics showed that the increase in the yield stress in the studied alloys is from 25% to 45% with relative to Cu-40% Ni alloy.

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

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.

Rapid Secondary Recrystallization of the Goss Texture in Fe81Ga19 Sheets Using Nanosized NbC Particles.

Herein, a simple and efficient method is proposed for fabricating Fe81Ga19 alloy thin sheets with a high magnetostriction coefficient. Sharp Goss texture ({110}<001>) was successfully produced in the sheets by rapid secondary recrystallization induced by nanosized NbC particles at low temperatures. Numerous NbC precipitates (size ~90 nm) were obtained after hot rolling, intermediate annealing, and primary recrystallization annealing. The relatively higher quantity of nanosized NbC precipitates with 0.22 mol% resulted in finer and uniform grains (~10 μm) through thickness after primary recrystallization annealing. There was a slow coarsening of the NbC precipitates, from 104 nm to 130 nm, as the temperature rose from 850 °C to 900 °C in a pure nitrogen atmosphere, as well as a primary recrystallization textured by strong γ fibers with a peak at {111} <112> favoring the development of secondary recrystallization of Goss texture at a temperature of 850 °C. Matching of the appropriate inhibitor characteristics and primary recrystallization texture guaranteed rapid secondary recrystallization at temperatures lower than 950 °C. A high magnetostriction coefficient of 304 ppm was achieved for the Fe81Ga19 sheet after rapid secondary recrystallization.

Primary Recrystallization Behaviors of Hi-B Steel with Lower Initial Nitrogen Produced by the Thin Slab Casting and Rolling Process

Based on low-temperature high-permeability grain-oriented silicon steel designed with an initial nitrogen content of 0.0055% and produced by the thin slab casting and rolling process, the effect of total nitrogen content and nitriding temperature on primary recrystallization microstructure and texture were studied by optical microscope, scanning electron microscope, transmission electron microscope, and electron backscatter diffraction. The nitriding temperature affects the primary recrystallization behaviors significantly, while the total nitrogen content has a small effect. As the nitriding temperature is 750–850 °C, the average primary grain size and its inhomogeneity factor are about 26.58–26.67 μm and 0.568–0.572, respectively. Moreover, the texture factor is mostly between 0.15 and 0.40. Because of the relatively sufficient inhibition ability of inherent inhibitors in a decarburized sheet, the nitriding temperature (750–850 °C) affects the primary recrystallization microstructure and texture slightly. However, as the nitriding temperature rises to 900–950 °C, the average primary grain size and its inhomogeneity factor increase to 27.75–28.26 μm and 0.575–0.578, respectively. Furthermore, because of the great increase on the area fraction of {112} &lt;110&gt; grains, part of texture factor is increased sharply. Therefore, in order to obtain better primary grain size and homogeneity, better texture composition, and stability of the decarburized sheet, the optimal nitriding temperature is 750–850 °C.

The role of grain colony on secondary recrystallization in grain-oriented electrical steel: New insights from an original tracking experiment

Secondary recrystallization is responsible for the sharp Goss texture ({110}<001>) of grain-oriented electrical steels. Many investigations have focused on establishing the relations between the sharpness of final Goss textures and primary recrystallization textures measured by the X-ray diffraction. However, the contributions of micro-texture characteristics to secondary recrystallization have not yet been well understood. Here, we report that the grain colonies composed of grains with similar orientations in the primary recrystallization matrix had a particular role on the development of secondary recrystallization via an original tracking experiment. We observe that the γ-grain (<111>//normal direction, ND) colonies facilitate the retention of primary recrystallization matrix grains (≤25µm) having 20-45° disorientation with {110}<001> and relatively large difference in the associated frequency with precise Goss orientation and that having deviation angle of 15°, promoting the abnormal growth of low-deviation-angle Goss grains especially after the onset of secondary recrystallization and leading to sharp final Goss texture. By contrast, the abnormal growth of high-deviation-angle Goss grains may be also promoted after the initiation of secondary recrystallization in case of randomly-distributed γ-grains in primary recrystallization matrix and thus resulted in deteriorated magnetic properties. In this way, we reveal the role of grain colony on secondary recrystallization and the underlying mechanism for the effect of primary recrystallization textures on the sharpness of final Goss texture. We also observe that the formation of grain colonies is mainly related to the initial solidification microstructure, processing route as well as the deformation and recrystallization features of γ-grains.

Effect of Nb content on primary recrystallization microstructure, texture and magnetic properties of grain-oriented silicon steel manufactured by low-temperature slab reheating

The influence of Nb content on the primary recrystallization microstructure, crystallographic texture and magnetic properties of grain-oriented silicon steel manufactured by low-temperature slab reheating were studied. The results show that the effect of grain refining was enhanced with the increase of Nb content. With the increase of Nb content, the total contents of texture {111}〈112〉 and {114}〈481〉 in primary recrystallization which are beneficial to the secondary recrystallization increased, but the contents of deviated Goss component and adverse textures with abnormal growth ability in primary recrystallization also increased, which led to the deterioration of magnetic properties. By adding 0.005% Nb, the average size of the primary grain reduced to 23 μm, the content of {110}〈112〉 increased slightly and the least deviated Goss nuclei were obtained, therefore the final product had the sharpest {110}〈001〉 texture of secondary recrystallization and the best magnetic properties with B800 = 1.873 T , P1.7/50 = 1.21 W/kg.

Secondary Recrystallization Goss Texture Development in a Binary Fe81Ga19 Sheet Induced by Inherent Grain Boundary Mobility

Secondary recrystallization Goss texture was efficiently achieved in rolled, binary Fe81Ga19 alloy sheets without the traditional dependence on inhibitors and the surface energy effect. The development of abnormal grain growth (AGG) of Goss grains was analyzed by quasi-situ electron backscatter diffraction (EBSD). The special primary recrystallization texture with strong {112}–{111}&lt;110&gt; and weak Goss texture provides the inherent pinning effect for normal grain growth by a large number of low angle grain boundaries (&lt;15°) and very high angle grain boundaries (&gt;45°) according to the calculation of misorientation angle distribution. The evolution of grain orientation and grain boundary characteristic indicates that the higher fraction of high energy grain boundaries (20–45°) around primary Goss grains supplies a relative advantage in grain boundary mobility from 950 °C to 1000 °C. The secondary recrystallization in binary Fe81Ga19 alloy is realized in terms of the controllable grain boundary mobility difference between Goss and matrix grains, coupled with the orientation and misorientation angle distribution of adjacent matrix grains.

Formation of island grains in high-permeability grain-oriented silicon steel manufactured by the acquired inhibitor method

In high-permeability grain-oriented silicon steel, island grains are often observed in the final sheets. In this work, the formation of island grains was studied in high-permeability grain-oriented silicon steel manufactured by the acquired inhibitor method. It was found that the {210}<001> and {110}<112> orientations dominated in the island grains. To understand the formation mechanisms of island grains, the grain boundary characteristics were investigated. Abnormal growth of island grains occurs because their orientations have a higher frequency of high-energy boundaries in the primary recrystallization texture. The {210}<001> grains could be left behind as island grains because they had a low misorientation angle with a Goss orientation (about 20°), whereas the {110}<112> island grains formed because of the size advantage of abnormally growing grains. The conclusions were also supported by the results of the interruption experiment. The {210}<001> grains were observed in the subsurface sheared area of the hot band and mainly nucleated at the subsurface layer during primary recrystallization. In addition, it was confirmed that the island grains (except for the exact {210}<001> orientation) had a negative influence on the magnetic properties because of the large deviation angle of the <001> axis from the rolling direction.

Investigation on the primary and secondary recrystallization textures of rare earth micro-alloyed grain-oriented silicon steel

The primary and secondary recrystallization textures of rare earth micro-alloyed grain-oriented electrical steel was examined by using electron backscattered diffraction (EBSD) techniques. The results show that the primary recrystallization texture comprises {111} < 112 >, {111}<110 >, {411}<148>, and {012} < 001> components. The benefiting texture components of primary recrystallization increase with increasing rare earth addition after decarburizing annealing. During secondary recrystallization, the proportion of Σ9 boundaries are reduced. The sample containing 5ppm rare earth starts secondary recrystallization at 900°C, and the sample containing of 17ppm rare earth starts secondary recrystallization at 950°. The addition of rare earth can delay the process of secondary recrystallization.

Effect of hot band annealing on texture and grain size distribution of primary recrystallization in grain-oriented silicon steel

During final high-temperature annealing in grain-oriented silicon steel, a few Goss grains grow exclusively fast and consume the matrix grains, which are related to the quality of the final product. The optimization of texture and microstructure in primary recrystallization is crucial to achieve the sharp Goss texture in grain-oriented silicon steel. The driving force for this phenomenon is the reduction of grain boundary area, which can be decribed as a reduction in grain boundary energy. The distribution of grain boundary and its energy determined by texture and microstructure of primary recrystallization are very important data to understand the optimization point. The hot band annealing is known to be a prerequisite for the high quality product in grain-oriented silicon steel. It can affect the evolution of microstructure and texture in primary recrystallization. In this study, the influence of the hot band annealing temperature on the texture and grain size distribution in primary recrystallization was investigated in detail.

Secondary recrystallization induced by composite precipitates in magnetostrictive Fe-Ga alloy thin sheet

Secondary recrystallization of Goss ({110} < 001>) texture is successfully produced by using nanometer-sized composite inhibitor in primary cold rolled Fe81Ga19 alloy sheet. Nanometer-sized sulfides consisting of MnS and Cu2S are dispersedly precipitated during hot rolling and normalization as inhibitors for secondary recrystallization. Strong γ texture with peak at {111} < 112> and weak Goss texture distributed through the sheet thickness in primarily annealed sheets can provide favorable environment for the secondary recrystallization. The higher onset and finishing temperatures of secondary recrystallization confirm the stronger inhibition and driving force originated from the composite inhibitors. Centimeter-sized Goss grains and large magnetostriction coefficient are obtained by primary cold rolling methods without surface energy effect. The result indicates that complete secondary recrystallization in Fe-Ga alloy can be realized by precisely controlling inhibitor characteristic and primary recrystallization texture.

Effect of Sn Addition on Evolution of Primary Recrystallization Texture in 3% Si Steel

Effect of Sn Addition on Evolution of Primary Recrystallization Texture in 3% Si Steel

Sharp secondary recrystallization and large magnetostriction in Fe81Ga19 sheet induced by composite nanometer-sized inhibitors

Abstract Strong Goss texture ({1 1 0}〈0 0 1〉) in Fe81Ga19 thin sheet is successfully produced by secondary recrystallization process based on the precise control of inhibitor and primary recrystallization texture. Nanometer-sized sulfides of MnS and Cu2S are dispersedly precipitated during hot rolling as inhibitors for secondary recrystallization. Primary recrystallization texture is characteristic of weak Goss and strong γ textures distributed through sheet thickness by appropriate rolling and annealing schedule. The composite nanometer-sized inhibitors accompanied with the primary recrystallization texture can provide a well-matched pinning effect on normal grain growth of matrix grains and induce abnormal grain growth of exact Goss grains in final annealing process. The magnetostriction coefficient as high as 285 ppm is obtained in Fe81Ga19 sheet after complete secondary recrystallization. Thus, an efficient method is proposed for developing sharp Goss texture and upgrading magnetostriction coefficient in Fe-Ga sheet.