Electrical Steels: Electrical Steels
Sponsored by: TMS Structural Materials Division, TMS: Steels Committee, TMS: Magnetic Materials Committee
Program Organizers: Youliang He, CanmetMATERIALS, Natural Resources Canada; Kester Clarke, Los Alamos National Laboratory; Jun Cui, Iowa State University

Wednesday 2:00 PM
March 22, 2023
Room: 33B
Location: SDCC

Session Chair: Youliang He, CanmetMATERIALS; Kester Clarke, Colorado School of Mines; Jun Cui, Iowa State University


2:00 PM  Invited
Report on Some Recent Progress on the Understanding of the Goss Texture in Fe-3 % Si Grain Oriented Electrical Steels: Dierk Raabe1; 1Max-Planck Institute
    The origin of the pronounced Goss texture formed in Fe-3 % Si grain oriented electrical steels is a problem long under debate. The presentation reviews and discusses some of recent findings on this texture component, considering aspects such as grain-boundary related growth advantages, grain-size related growth advantages, the role of through-process texture inheritance, particle pinning-related differences in growth, and the role of chemical partitioning between several types of lattice defects. A set of tools is used for this purpose, including XRD, 2D EBSD, 3D EBSD, ECCI, TEM, EDX and APT.

2:30 PM  
Effect of Rare Earth Yttrium on Inclusion and Texture of Oriented Silicon Steel: Zhihong Guo1; Xiangyang Li1; Yaxu Zheng1; Liguang Zhu1; Yuanxiang Zhang2; Huilan Sun1; Ruifang Cao3; 1Hebei University of Science and Technology; 2Northeastern University; 3Beijing Shougang Co., LTD
    Scanning electron microscope (SEM) and electron backscatter diffraction (EBSD) were used to study the precipitation behavior, microstructure and texture evolution of the second phase in Y-oriented silicon steel. The results show that after the addition of rare earth Y, the inclusions are mainly spherical or ellipsoidal Y2O2S, which can effectively inhibit the precipitation of elongated MnS inclusions in the hot-rolled sheet. Rare earth treatment reduced the total number of inclusions by 14%, of which small inclusions decreased by 18% and large inclusions increased by 3.5%, but the average size of total inclusions increased by only 0.24 μm. The addition of rare earth Y reduces the unfavorable brass texture in the hot-rolled sheet, increases the number of shear bands in the cold-rolled sheet, and improves the strength of the {111}<112> texture in the decarburized sheet. After high temperature annealing, perfect secondary recrystallization occurred, and excellent magnetic properties were obtained.

2:50 PM  
Microstructure and Texture Evolution of High Grade Non-oriented Electrical Steel for New Energy Vehicles during Hot Rolling: Xueying Lv1; Wanlin Wang1; Peisheng Lv1; Huihui Wang1; Yunli Zhang1; Lulu Song1; 1Central South University
    As the most important iron core material in the motor of new energy vehicles, the development of high magnetic induction, low iron loss, thin specification of non-oriented electrical steel production and preparation process is an effective way to alleviate energy shortage, improve environmental pollution and promote sustainable development. Based on the advanced ultra-thin strip casting technology, the effect of different hot-rolling parameters on the deformation and texture of Fe-3.5 wt% Si non-oriented electrical steel was investigated, and characterized by backscattered electron diffraction (EBSD) and X-ray diffraction (XRD). The results show that the texture changes dramatically with the increase of rolling temperature, and the increase of the reduction ratio leads to the increase of deformation bands and the diversification of texture rotation. Therefore, by optimizing the process parameters of hot-rolling, more textures beneficial to magnetic properties can be obtained, which is of great significance for the subsequent improvement of product performance.

3:10 PM  
A New Approach to Optimise the Microstructure of Non-oriented Electrical Steel Sheets: Saeed Tamimi1; Youliang He2; Winfried Kockelmann3; Leo Kestens4; 1AFRC- University of Strathclyde; 2CanmetMATERIALS; 3Science and Technology Facilities Council (STFC), Rutherford Appleton Laboratory, ISIS Facility; 4Ghent University
    It is well established that shear plastic deformation together with annealing can promote the formation of <100> in non-oriented electrical steel (NOES) sheets. This shear plastic deformation can be achieved through repetitive bending and unbending. This work introduces a novel deformation process of repetitive-bending-under-tension (RBUT) to modify the texture of a NOES sheet. In this process, the strips are subjected to repetitive bending and unbending by sliding a set of rollers over the length of the piece when pulled under tension. The deformed strips were then heat-treated under different conditions. Macro- and micro-texture characterisation confirmed that the RBUT process significantly reduced the undesired {111} texture while promoting the {001} texture. The results also indicated that the metallic strips subjected to RBUT could be deformed uniformly and beyond their standard formability limit. This may provide an alternative technique to address the poor workability challenge of high-silicon-NOES sheets.

3:30 PM Break

3:45 PM  Invited
The Processing and Application of Fe-6.5%Si Ribbons and Flakes: Gaoyuan Ouyang1; Iver Anderson1; Matthew Kramer1; Jun Cui2; 1Ames Laboratory; 2Iowa State University
    The performance of electrical steel depends on its silicon content. Fe-6.5%Si has higher resistivity and lower iron losses than the widely used Fe-3.2%Si. However, Fe-6.5%Si is difficult to fabricate using the traditional cold-roll process since the ordered phases formed during the process embrittle the alloy. Rapid solidification is a viable route to fabricate Fe-6.5%Si thin sheet since it suppresses the embrittling ordered phases. We have established the relationship among cooling rate, chemical ordering, mechanical, and magnetic properties of Fe-6.5%Si during the melt spinning process, which lays the foundation for preparation Fe-6.5%Si ribbon with a tunable ductility. We constructed standard stack laminates for motor stators using Fe-6.5%Si, and developed a novel ribbon bundle stator concept that uses Fe-6.5%Si narrow ribbons. We also developed novel melt spinning techniques that directly yield ductile Fe-6.5%Si flakes, which can be coated and consolidated into near net shape motor stators or inductors.

4:15 PM  
Constitutive Modelling of High-temperature Flow Behavior of a Non-oriented Electrical Steel with 3.2 wt% Si: Gyanaranjan Mishra1; Kanwal Chadha1; Youliang He2; Clodualdo Aranas1; 1University of New Brunswick; 2CanmetMaterials
    The high-temperature deformation behavior of electrical steel is an important material parameter for the optimization of the hot rolling process, which has not been paid close attention in electrical steel research. In this study, hot compression tests were performed on two non-oriented electrical steels containing 1.2 and 3.2 wt % Si. The samples were deformed up to a true strain of 0.7 at strain rates varying between 0.01 and 1 s-1, and temperatures ranging from 850 to 1050 °C. The stress-strain data was fitted using various constitutive models, and evaluated using the correlation coefficient (R) and the average absolute relative error (AARE). It was shown that the modified Zerilli-Armstrong model provided excellent prediction of the flow stress in a wide range of strain, strain rate and temperature. Microstructure examination was performed to unravel the differences between materials with and without phase transformation during high-temperature deformation of the two different grades.

4:35 PM  
Effect of Cold Rolling Reduction Rate and Rare Earth Yttrium on Microstructure and Texture of Oriented Silicon Steel: Zhihong Guo1; Pengjun Liu1; Yaxu Zheng1; Liguang Zhu1; Yuanxiang Zhang1; Huilan Sun1; Ruifang Cao1; 1Hebei University of Science and Technology
     In order to explore the effect of deformation on structure and texture of 3% Si oriented silicon steel with and without Y, three different cold rolling reduction rates were carried out by using EBSD and image analysis software. The experimental results show that the density of internal shear bands gradually increases with the increase of cold rolling deformation. When the cold rolling reduction rate reaches 86%, there are lower density and strength shear bands. The grain size of cold rolled sheet containing rare earth Y was long. There are higher density and strength shear bands. The texture intensity of the cold rolled sheet is proportional to the reduction rate. However, the strength of textures decreases with increasing the reduction rate above 80%. Y greatly weakens the intensity of main texture.The γ texture strength is 7.3 in cold rolled sheet containing Y, which is significantly higher than that without Y.

4:55 PM  
The Role of Temper Rolling and Annealing on the Magnetic Property Improvement of a Low Si Non-oriented Electrical Steel: Youliang He1; Tihe Zhou2; Haden Lee2; Chad Cathcart2; Peter Badgley2; 1CanmetMATERIALS, Natural Resources Canada; 2Stelco Inc.
    Temper rolling and the following annealing have a considerable effect on the magnetic properties of electrical steel. In this study, a low Si non-oriented electrical steel was hot rolled, cold rolled and batch annealed to produce 0.5-mm-thick sheets. Temper rolling (5~8% reduction) was then applied to the annealed sheets which were annealed again at different temperatures (500 to 900 °C) for a fixed annealing time (2 h) or at a fixed temperature (800 °C) for different times (0.5 - 24 h). It was found that temper rolling and annealing could significantly improve the magnetic properties, i.e., decreasing the core loss by up to ~22% and increasing the relative permeability by up to 68% at 1.5 T and 60 Hz, as compared to that without temper rolling. The improvement of magnetic properties was correlated to the changes in microstructure and texture induced during the temper rolling and final annealing processes.