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.

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.

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.

The Research of Non-Oriented Electrical Steel Processed by Stress Relief Annealing Experiments

2014 ◽  
Vol 887-888 ◽  
pp. 252-256
Author(s):  
Zhun Li ◽  
Jing Liu ◽  
Shi De Li ◽  
Ze Lin Zheng
Keyword(s):  
Magnetic Properties ◽  
Electrical Steel ◽  
Core Loss ◽  
Reference Method ◽  
Stress Relief ◽  
Hydrogen Atmosphere ◽  
Silicon Steel ◽  
Pure Hydrogen ◽  
Final Annealing ◽  
Annealing Experiments

A high grade non-oriented electrical steel final annealing product was processed by stress relief annealing experiments under pure hydrogen atmosphere using different process parameters. The samples were compared in the aspects of magnetic properties and anisotropy, then analyzed the phenomena concerned with grain size, texture and precipitates aspects. The experiments showed that the samples magnetic properties were most improved in the 850 degrees stress relief annealing experiment, thus providing a reference method for non-oriented silicon steel stress relief annealing experiments and to obtain low core loss non-oriented silicon steel.

The Effects of Hot Band Annealing Temperature on the Texture of 2%Si Nonoriented Electrical Steel

2007 ◽  
Vol 550 ◽  
pp. 527-532 ◽  
Author(s):  
Jae Young Choi ◽  
Chel Min Park ◽  
Jong Tae Park ◽  
Jae Kwan Kim
Keyword(s):  
Magnetic Flux ◽  
Flux Density ◽  
Annealing Temperature ◽  
Electrical Steel ◽  
Cube Texture ◽  
Magnetic Flux Density ◽  
Middle Plane ◽  
Goss Texture ◽  
Final Annealing ◽  
Hot Band

The effects of hot band annealing temperature on the texture of the 2%Si nonoriented electrical steel were investigated. Slab was hot rolled and then hot band annealed in the temperature range of 900°C~1100°C. The magnetic flux density and the core loss were improved by the hot band annealing because of the texture improvement. As the hot band annealing temperature was increased, the magnetic properties were improved. The microstructure of the hot band was composed of a recrystallized structure at the surface and a deformation structure near the middle plane. These hot bands were completely recrystallized after annealing above 1000°C. The main texture of the hot band was rotated cube and gamma-fibre. After hot band annealing, rotated cube changed to cube texture and gamma-fibre intensity gradually decreased. In the case of non-annealed hot band, rotated cube in the middle plane was changed to near {111}<112>texture and Goss texture in the surface to gamma fibre after final annealing. In the case of the hot band annealed at 900°C, rotated cube near the middle plane changed to Goss texture and Goss texture in the surface to rotated cube after final annealing. After final annealing, the {111} and {112} texture was dramatically decreased as the hot band annealing temperature was higher. The total {100} texture intensity was not changed. Cube texture {100}<001> increased and rotated cube texture {100}<011> decreased. The {110} texture increased after hot band annealing irrespective of temperature. As the hot band annealing temperature was higher, the Goss texture increased, and this increase of Goss texture causes the anisotropy of the magnetic flux density.

Production of Electrical Steel by Hot Dipping in Aluminium

2008 ◽  
Vol 273-276 ◽  
pp. 63-68
Author(s):  
Pablo Rodriguez-Calvillo ◽  
P. Bernárdez ◽  
Yvan Houbaert
Keyword(s):  
Steel Substrate ◽  
Low Carbon Steel ◽  
Annealing Treatment ◽  
Processing Route ◽  
Favourable Effect ◽  
Carbon Substrate ◽  
Diffusion Annealing ◽  
Pure Aluminium ◽  
Low Carbon ◽  
Power Losses

The addition of aluminium (and of silicon) to steel increases its electrical resistivity and reduces therefore the power losses in electrical devices. There is also a favourable effect on magnetostriction. Nevertheless, these additions make the steel extremely brittle and very difficult to process through a conventional thermomechanical route. The authors developed an innovative processing route, avoiding the rolling of a brittle steel sheet. The used process consists of the hot dipping of a steel substrate in a pure aluminium bath, followed by a diffusion annealing treatment. In order to study the reaction of the aluminium with the substrates and the diffusion process during further annealing, two substrates (ultra low carbon steel (ULC) and a Fe + 3.4 m.-% Si steel) were used for immersion in a pure aluminium bath. Dipping times and temperatures were varied in the range of 700 to 750 °C and 5 to 1000 sec., respectively. The different surface layers formed during dipping and after annealing were characterised with an Elcometer, by Scanning Electron Microscopy (SEM) and by Energy Dispersive Spectroscopy (EDS). The results show that the chemical composition of the layers obtained is strongly dependant on the initial substrate composition. Diffusion gradients of Al and Si in the steel after hot dipping and diffusion annealing are shown and discussed. Samples with a concentration gradient of Si and Al over the thickness have been produced. There is only a light reduction of the power losses for the substrate with 3.4 m.-% Si. The ultra low carbon substrate presents worse power losses after the processing. Further improvement of the processing is still required.

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.

Magnetic Barkhausen Noise Characterization of the Recrystallization of a Non-Oriented Electrical Steel after Cold Rolling at Different Angles to the Hot Rolling Direction

2018 ◽  
Vol 941 ◽  
pp. 274-279
Author(s):  
You Liang He ◽  
Mehdi Mehdi ◽  
Erik J. Hilinski ◽  
Afsaneh Edrisy
Keyword(s):  
Magnetic Properties ◽  
Cold Rolling ◽  
Hot Rolling ◽  
Electrical Steel ◽  
Electron Backscatter Diffraction ◽  
Rolling Direction ◽  
Barkhausen Noise ◽  
Magnetic Barkhausen Noise ◽  
Final Annealing ◽  
Steel Sheets

Non-oriented electrical steel sheets are the most commonly used material for the manufacturing of magnetic cores for electric motors and generators. The microstructure and texture of the steel after final annealing have a significant effect on the magnetic properties of the lamination core. To investigate the effect of cold rolling and annealing on the magnetic properties of the steel sheets, a 0.9 wt% Si non-oriented electrical steel was cold rolled at different angles to the hot rolling direction (HRD) and annealed at various temperatures (600°C to 750°C) to produce dissimilar microstructures. The progress of recrystallization was characterized by electron backscatter diffraction (EBSD), and the magnetic response of the steel at various stages of recrystallization was evaluated by magnetic Barkhausen noise (MBN). A number of MBN parameters, e.g. the root mean square, the smoothed envelope, the peak, the full width at half maximum (FWHM) of the envelope, the time integral of the MBN signals and the MBN energy, were analyzed with respect to the fraction of recrystallization during annealing. The results show that cold rolling at different angles to the hot rolling direction induces various deformation microstructures and stored energies, which, in turn, lead to considerably different recrystallization behaviours during annealing. The difference in recrystallization of these materials is also reflected in the MBN parameters.

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