Effect of Hot Band Annealing on the Microstructure and Mechanical Properties of Low Carbon Electrical Steels

2010 ◽  
Vol 1276 ◽  
Author(s):  
E. Gutiérrez-Castañeda ◽  
A. Salinas-Rodríguez
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Magnetic Properties ◽  
Tensile Properties ◽  
Electrical Steel ◽  
Processing Route ◽  
Rolled Strip ◽  
Final Annealing ◽  
Electrical Steels ◽  
Hot Rolled

AbstractMagnetic properties of grain non-oriented low-C electrical steels are improved when the hot rolled strip is annealed (HBA) prior to cold rolling and final annealing treatments. This improvement results from development of a {100}<uvw> texture in the large grained ferrite microstructure produced during final annealing. HBA at 800–850 °C results in rapid decarburization and elimination of carbide particles which have caused concerns about the suitability of the mechanical properties in the final product. In this work, samples taken from a hot rolled electrical steel coil are subjected to HBA during 150 minutes at 850 °C, cold rolled and finally annealed three minutes at temperatures between 700 and 1000 °C. The resulting tensile properties are compared with those of samples subjected to a similar processing route but without the HBA treatment and samples of industrially semi-processed grain non-oriented electrical steel decarburized 16 hours at 750 °C. It is shown that the yield strength of samples with and without HBA depends on the final grain size according to the Hall-Petch relationship; the final grain size depends strongly on annealing temperature. However, the HBA treatment causes the strength to decrease by a factor of about 2.5 and the ductility to increase by a factor of about 1.5. It is observed that the microstructure and tensile properties of the semi-processed electrical steel subjected to a final decarburization annealing are identical to those observed in material subjected to HBA in the present work. These results indicate that the HBA treatment not only improves the magnetic properties but also leads to a significant reduction of production time for grain non-oriented electrical steels.

Texture and Microstructure Evolution during Box Annealing of a Non-Oriented-Grain Electrical Steel

2011 ◽  
Vol 702-703 ◽  
pp. 595-598
Author(s):  
Francisco N.C. Freitas ◽  
Manoel Ribeiro da Silva ◽  
Sergio S.M. Tavares ◽  
Hamilton F.G. Abreu
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Cold Rolling ◽  
Crystallographic Texture ◽  
Electrical Steel ◽  
Electron Backscatter Diffraction ◽  
Magnetization Direction ◽  
Electrical Steels ◽  
Cold Rolling And Annealing ◽  
Work Samples

Non-oriented grain type electrical steels are used mainly in electrical rotating machines such as motors and compressors, in which the magnetization direction rotates 360 ° every cycle while remaining in the plane of the plate. The performance of these devices is affected by crystallographic texture of electrical steels due to strong anisotropy of magnetic properties. The electrical steel is supplied in the form of plates which are processed by cold rolling and subsequent annealing. Both, cold rolling and annealing directly influence the formation of crystallographic texture components. During annealing, recrystallization occurs, and this phenomenon gives rise to changes in texture that influences the quality of the final product and its application. Several works have been published in the study of the evolution of crystallographic texture and grain size in this type of electrical steel. In this work, samples have been taken in industrial conditions at various temperatures during the annealing in a coil box. Electrical steel samples cold rolled with reductions of 50% and 70% in thickness were removed during the process of annealing, and the evolution of texture with increasing temperature was studied. Aspects related to recrystallization, grain size and the evolution of texture and magnetic properties were discussed. Texture and recrystallization were studied by X-ray diffraction and electron backscatter diffraction (EBSD). The magnetic properties were measured in a vibrating sample magnetometer.

scholarly journals Integrated Process Simulation of Non-Oriented Electrical Steel

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6659
Author(s):  
Anett Stöcker ◽  
Max Weiner ◽  
Grzegorz Korpała ◽  
Ulrich Prahl ◽  
Xuefei Wei ◽  
...  
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Cold Rolling ◽  
Process Parameters ◽  
Hot Rolling ◽  
Electrical Steel ◽  
Sheet Thickness ◽  
Electrical Steels ◽  
Heterogeneous Microstructures ◽  
The Impact

[d=A]A tailor-made microstructure, especially regarding grain size and texture, improves the magnetic properties of non-oriented electrical steels. One way to adjust the microstructure is to control the production and processing in great detail. Simulation and modeling approaches can help to evaluate the impact of different process parameters and finally select them appropriately. We present individual model approaches for hot rolling, cold rolling, annealing and shear cutting and aim to connect the models to account for the complex interrelationships between the process steps. A layer model combined with a microstructure model describes the grain size evolution during hot rolling. The crystal plasticity finite-element method (CPFEM) predicts the cold-rolling texture. Grain size and texture evolution during annealing is captured by the level-set method and the heat treatment model GraGLeS2D+. The impact of different grain sizes across the sheet thickness on residual stress state is evaluated by the surface model. All models take heterogeneous microstructures across the sheet thickness into account. Furthermore, a relationship is established between process and material parameters and magnetic properties. The basic mathematical principles of the models are explained and demonstrated using laboratory experiments on a non-oriented electrical steel with 3.16 wt.% Si as an example. Improving the magnetic properties of non-oriented electrical steels are of high interest. In this context, improvement by a tailor-made microstructure, especially regarding grain size and texture, is one focus. One way to adjust the microstructure is to control the production and processing in great detail. Simulation and modeling approaches, emphasizing grain size and texture development, can help to evaluate and finally set process parameters. Here, we present individual model approaches for hot rolling, cold rolling, annealing and shear cutting and aim to connect the models to account for the complex interrelationships between the process steps. Furthermore, a connection between the process parameters and the magnetic properties is drawn. Grain size, grain size distribution, texture and dislocation density are the main transfer parameters in between the models. All models take heterogeneous microstructures across the sheet thickness into account. The basic mathematical principles of the models are explained, and a case study is presented in each case using FeSi3.2wt%Si as an example material.

scholarly journals Material Design for Low-Loss Non-Oriented Electrical Steel for Energy Efficient Drives

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6588
Author(s):  
Nora Leuning ◽  
Markus Jaeger ◽  
Benedikt Schauerte ◽  
Anett Stöcker ◽  
Rudolf Kawalla ◽  
...  
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Electrical Steel ◽  
Sheet Thickness ◽  
Material Design ◽  
Material Behavior ◽  
Nonlinear Material ◽  
Design Stage ◽  
Electrical Machine ◽  
Electrical Steels

Due to the nonlinear material behavior and contradicting application requirements, the selection of a specific electrical steel grade for a highly efficient electrical machine during its design stage is challenging. With sufficient knowledge of the correlations between material and magnetic properties and capable material models, a material design for specific requirements can be enabled. In this work, the correlations between magnetization behavior, iron loss and the most relevant material parameters for non-oriented electrical steels, i.e., alloying, sheet thickness and grain size, are studied on laboratory-produced iron-based electrical steels of 2.4 and 3.2 wt % silicon. Different final thicknesses and grain sizes for both alloys are obtained by different production parameters to produce a total of 21 final material states, which are characterized by state-of-the-art material characterization methods. The magnetic properties are measured on a single sheet tester, quantified up to 5 kHz and used to parametrize the semi-physical IEM loss model. From the loss parameters, a tailor-made material, marked by its thickness and grain size is deduced. The influence of different steel grades and the chance of tailor-made material design is discussed in the context of an exemplary e-mobility application by performing finite-element electrical machine simulations and post-processing on four of the twenty-one materials and the tailor-made material. It is shown that thicker materials can lead to fewer iron losses if the alloying and grain size are adapted and that the three studied parameters are in fact levers for material design where resources can be saved by a targeted optimization.

Recrystallisation, Grain Growth and Texture Evolution in Nonoriented Electrical Steels

2007 ◽  
Vol 558-559 ◽  
pp. 657-664 ◽  
Author(s):  
Jong Tae Park ◽  
Jae Kwan Kim ◽  
Jerzy A. Szpunar
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Grain Growth ◽  
Texture Evolution ◽  
Size Control ◽  
Goss Texture ◽  
Final Annealing ◽  
Electrical Steels ◽  
Grain Size Control ◽  
Specific Orientation

The magnetic properties of nonoriented electrical steels are influenced by grain size and texture of final products. The key technology in the commercial production of nonoriented electrical steels is to grow grains with {hk0}<001> texture up to the optimum size in the final annealing process. The problems related to grain size control have been extensively investigated, while texture control has received much less attention. Therefore, there is enough room to improve the magnetic properties through the control of texture. In this study, systematic investigations on the texture evolution during both recrystallization and grain growth have been made. The formation of recrystallization texture is explained by oriented nucleation. This is supported by the fact that the area fraction of nuclei or recrystallized grains with specific orientation to all new grains remains almost constant during the progress of recrystallization. Most nuclei have a high misorientation angle of 25∼55° with the surrounding deformed matrices. During the progress of grain growth, the Goss texture component continues to decrease because the Goss grains have a high percentage of low angle, low mobility grain boundaries. The grains of Goss orientation have a smaller grain size than those of random orientation.

Effect of Hot Band Annealing on Microstructure of Semi-Processed Non-Oriented Low Carbon Electrical Steels

2009 ◽  
Vol 1243 ◽  
Author(s):  
Emmanuel J. Gutiérrez ◽  
Castañeda ◽  
Armando Salinas Rodriguez
Keyword(s):  
Magnetic Properties ◽  
Electrical Steel ◽  
Annealing Treatment ◽  
Processing Route ◽  
Attractive Alternative ◽  
Low Carbon ◽  
Production Scale ◽  
Final Annealing ◽  
Steel Strips ◽  
Hot Band

ABSTRACTEffects of hot band annealing on the final microstructure and magnetic properties of cold rolled and annealed non-oriented grain Si-Al electrical steel strips are investigated. Microstructures are characterized using optical and scanning electron microscopy and magnetic properties are determined using a vibrating sample magnetometer. It is shown that annealing of hot rolled bands at temperatures between 800 and 850 °C causes rapid decarburization and development of a microstructure consisting of large columnar ferrite grains free of secondary particles. This microstructure leads, after cold rolling and a fast annealing treatment, to large grain microstructures similar to those observed in production scale, fully processed strips. It is observed that the final grain size increases with the final annealing temperature, leading to a significant improvement of the magnetic properties. Therefore, hot band annealing technology can be an attractive alternative processing route for the manufacture of non-oriented grain low carbon Si-Al processed electrical steel strips.

scholarly journals Influence of Process Parameters on Grain Size and Texture Evolution of Fe-3.2 wt.-% Si Non-Oriented Electrical Steels

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6822
Author(s):  
Xuefei Wei ◽  
Alexander Krämer ◽  
Gerhard Hirt ◽  
Anett Stöcker ◽  
Rudolf Kawalla ◽  
...  
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Cold Rolling ◽  
Process Parameters ◽  
Hot Rolling ◽  
Electrical Steel ◽  
Texture Evolution ◽  
Laboratory Scale ◽  
Process Chain ◽  
Final Annealing

The magnetic properties of non-oriented electrical steel, widely used in electric machines, are closely related to the grain size and texture of the material. How to control the evolution of grain size and texture through processing in order to improve the magnetic properties is the research focus of this article. Therefore, the complete process chain of a non-oriented electrical steel with 3.2 wt.-% Si was studied with regard to hot rolling, cold rolling, and final annealing on laboratory scale. Through a comprehensive analysis of the process chain, the influence of important process parameters on the grain size and texture evolution as well as the magnetic properties was determined. It was found that furnace cooling after the last hot rolling pass led to a fully recrystallized grain structure with the favorable ND-rotated-cube component, and a large portion of this component was retained in the thin strip after cold rolling, resulting in a texture with a low γ-fiber and a high ND-cube component after final annealing at moderate to high temperatures. These promising results on a laboratory scale can be regarded as an effective way to control the processing on an industrial scale, to finally tailor the magnetic properties of non-oriented electrical steel according to their final application.

Characterization of Electron Beam Welded Non-Oriented Electrical Steel with Magnetic Barkhausen Noise

2014 ◽  
Vol 605 ◽  
pp. 39-42 ◽  
Author(s):  
Polykseni Vourna
Keyword(s):  
Mechanical Properties ◽  
Magnetic Properties ◽  
Electron Beam ◽  
Electrical Steel ◽  
Electron Beam Welding ◽  
Magnetic Measurements ◽  
Barkhausen Noise ◽  
Magnetic Barkhausen Noise ◽  
Electrical Steels

In this paper the influence of Electron Beam Welding (EBW) on the microstructure, mechanical and magnetic properties of Non-Oriented Electrical steels was presented and evaluated. Single pass welds free of defects were produced at welding speeds and pulsed currents following a predesigned protocol. The samples microstructure and the macrohardness tests were concluded with the magnetic measurements (Barkhausen Noise) in order to correlate the structural and mechanical properties with the magnetizing behavior of Non-Oriented Electrical Steel.

Texture Development during Final Annealing in Nonoriented Electrical Steels

2005 ◽  
Vol 495-497 ◽  
pp. 471-476 ◽  
Author(s):  
Jong Tae Park ◽  
Jerzy A. Szpunar ◽  
Jae Kwan Kim
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Grain Growth ◽  
Recrystallization Texture ◽  
Core Loss ◽  
Size Control ◽  
Final Annealing ◽  
Electrical Steels ◽  
Texture Change ◽  
Grain Size Control

Nonoriented electrical steels have been widely used as core materials in motors and generators. For these applications low core loss and high permeability are required. The magnetic properties of these steels depend on the grain size and crystallographic texture of the annealed final products. The problems related to grain size control have been extensively investigated, while texture control has received much less attention. The technologies used to control the grain size in nonoriented electrical steels have approached to their limits. However, there is still some possibility for improvement of the magnetic properties through texture control. In order to explore this possibility, the evolution of recrystallization texture for nonoriented electrical steels with 2% Si was systematically studied. Texture change during grain growth was additionally analyzed. The formation of recrystallization texture is explained by oriented nucleation. This is supported by the fact that the area fraction of nuclei or recrystallized grains with specific orientation to all new grains remains almost constant during the progress of recrystallization. Most nuclei have a high misorientation angle of 25~55° with the surrounding deformed matrices. During the progress of grain growth, Goss and {111}<112> components are weakened and the random texture is strengthened. The grains of the Goss and {111}<112> orientations have smaller grain size than those of random orientation.

Comprised of the Organization and Performance of Non-Oriented Electrical Steel with Cold and Heat Slab

2016 ◽  
Vol 852 ◽  
pp. 181-186
Author(s):  
Tie Ye ◽  
Zhen Yu Gao ◽  
Zhi Wen Lu ◽  
Zhi Guo Zhong
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Cold Rolling ◽  
Electrical Steel ◽  
Annealing Process ◽  
Rolled Plate ◽  
Continuous Annealing ◽  
Production Test ◽  
Second Phase ◽  
Hot Rolled

The structure, texture, second phase and magnetic properties of non-oriented electrical steel with cold and heat slab were comprised through the production test. The research result shows that the grain size of hot rolled plate by cold slab is less than that of hot rolled plate by hot slab. But after cold rolling and annealing process, the grain size is consistent. Microstructure of hot rolled coil is recrystallized microstructure and the dispersion degree of texture orientation is high. Deformation makes the texture enhancement in cold rolling which become the strong texture based on {001} {111} and <110> texture. The Ti element has aggregation which can form hard impurities as TiN and TiSN to obstruct the recrystallization. Micro fine TiC formed in the annealing process which would block magnetic domain movement and reduce the magnetic properties of the product. MnS is precipitated impurities and the coarsening of MnS phase can reduce the domain block by improving the continuous annealing temperature and the magnetic field would be optimization.

Processing and Microstructure of Grain Non-Oriented Electrical Steel Strips with Improved Magnetic Properties

2012 ◽  
Vol 706-709 ◽  
pp. 2800-2805 ◽  
Author(s):  
Armando Salinas-Rodríguez ◽  
E. Gutiérrez-Castañeda
Keyword(s):  
Magnetic Properties ◽  
Cold Rolling ◽  
Electrical Steel ◽  
Steel Strip ◽  
Annealing Treatment ◽  
Fiber Texture ◽  
Processing Route ◽  
Attractive Alternative ◽  
Final Annealing ◽  
Alternative Processing

The effects of annealing prior to cold rolling on the microstructure and magnetic properties of a low-C grain non-oriented (GNO) electrical steel strip have been investigated. It is shown that annealing of the hot-rolled strips in the intercritical region, Ac13, causes rapid decarburization and development of large columnar ferrite grains. This microstructure leads, after cold-rolling and a fast annealing treatment at temperatures between 800 and 850 °C, to a polygonal ferrite grain microstructure with magnetic properties superior to those observed typically in the same steel in the industrial fully processed condition. The results are attributed to the {100}-fiber texture developed during the final annealing. Annealing at T<800 °C or T>850 °C results in formation of {111}-fiber texture components due to recristallization or transformation of deformed ferrite leading to a negative effect on the final magnetic properties. The results suggest that annealing prior to cold rolling offers an attractive alternative processing route for the manufacture of fully processed low-C, Si-Al GNO electrical steels strips.

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