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AC magnetic properties of grain-oriented
electrical steel sheet under DC-biased
magnetization in direction perpendicular to AC
magnetization
Electrical steel sheet have been widely employed as a magnetic core material of electromagnetic equipments. Magnetic materials in the equipments may be excited under
AC-magnetization with DC-biased magnetization. AC magnetic properties under DC-biased magnetization in the direction parallel to the AC magnetization have been
reported. However, the AC magnetic properties under DC-biased magnetization in the direction different from the AC magnetization have been scarcely researched. In this
research, we have examined the AC magnetic properties of grain-oriented electrical steel sheet under DC-biased magnetization in the direction perpendicular to AC
magnetization. We have found that the DC-biased magnetization dependence of the iron loss of grain-oriented electrical steel sheet differs in the rolling direction and the
transverse direction of the sheet. The difference between the iron loss properties has been explained from the point of view of the magnetic domain structure in the
respective magnetization processes.
Shunji YANASE
Gifu University
Alternating and rotational losses up to magnetic
saturation in non-oriented steel sheets
The design of efficient electrical machines depends on complete and precise knowledge of the loss properties of the materials employed in the magnetic core. The required
characterization, however, can be pretty difficult when the actual working regimes of the core, including distorted induction, two-dimensional fluxes, and peak polarization
values close to saturation, must be emulated in measurements. In order to comply with such special measuring conditions, we have developed a three-phase magnetizer,
designed with the help of 3D finite elements calculations, by which we have characterized non-oriented Fe-Si steels sheets under alternating and rotational flux up to
polarization value Jp 0.97Js, where Js is the saturation magnetization. The measurements, performed in the frequency range 5 Hz - 200 Hz, required combination of
fieldmetric and thermometric methods, besides fine control of the induction waveshape/loci under the required demanding exciting conditions. By applying the loss
separation concept to the energy loss versus frequency behavior, it is experimentally observed that under rotational flux not only the hysteresis loss component eventually
disappears at saturation, but that the same occurs for the excess loss, so that the total loss is reduced to the classical component. This could actually be predicted, because
of the expected disappearance of the domain walls under saturating rotational field, but it has never been previously verified by the experiments.
Carlo Ragusa
Politecnico di Torino - Energy Department, Corso
Duca degli Abruzzi 24, 10129 Torino, Italy
AN EXPERIMENTAL STUDY ON MAGNETIC
AGEING OF ELECTRICAL STEEL
Laminated electrical steel is considered an elementary constructional material of electrical machine cores. The efficiency and operating conditions of such machine depend
heavily on the steel quality, which is determined basically by its magnetic properties including permeability and core losses. During the service life of motors, a progressive
change in the steel magnetic properties can be observed over time, which leads to a deterioration in the steel performance associated with an increase in the precipitate
fraction. The aforementioned phenomenon is referred to as magnetic ageing. In this work, magnetic ageing was simulated by means of heat treatment for non-oriented
electrical steel at 225o C for a total time period of 80 hours. Magnetic measurements were carried out by a Single Sheet Tester (SST) at various frequencies (50 Hz-1 kHz)
and induction levels (0.1-1.5 T). Scanning Electron Microscope (SEM) was employed to investigate the grain size and precipitate fraction before and after heat treatment.
Texture analysis was done using X-ray Diffraction. Results show that Grain size and precipitate fraction increased after heat treatment whereas texture factor was almost
constant. Core loss (static and dynamic) decreased after heat treatment which confirms that magnetic ageing is not only dependent on precipitate fraction but also on
other factors such as grain size and texture.
Omar Saeed
McGill University
Anisotropy in Non-Oriented Electrical Steels
Non-Oriented electrcial steels can present texture, and this results in significant anisotropy of magnetic properties. In the present study, the anisotropy of magnetic
properties is evaluated with a model, based on the Orientation Distribution Function (ODF) theory. It follows that the anisotropy could be described by a function: A = Ao +
A1 Cos (2B) + A2 Cos (4B), where B is the angle between rolling direction and measurement direction. A0, A1, A2 are experimental constants. It is discussed how to find the
A1/A2 ratio directly from the ODF theory. Results from texture measurement ( Schulz pole figure) are compared with magnetic properties. The model is very adequate for
B50 and B25 evaluation. Losses can also be well described by the model. However, permeability mi15 is not so well described by the model, because in this region there is
significant domain wall displacement processes, and the model considers domain rotation. The current standard for Epstein measurement recommends measurement at
the transverse direction (TD) and the rolling direction (RD), and the magnetic property is given by the average (50%RD+50%TD) RD=0o and TD=90o The Epstein Standard
can be improved with an extra measurement at 45o and the value of the property be given by the formula Ao= (A(0o) + A(90o) + 2A(45o))/4
Marcos Flavio de Campos
Universidade Federal Fluminense
Grain-oriented steels, non-oriented electrical
steels high silicon sheets
Effect of carbon content on magnetic ageing
index and mechanical properties of NOG 2%Si.
This work studied the effect of carbon content on the evolution of the magnetic ageing index and the mechanical properties on cold rolled samples of 2% Si non-oriented
electrical steel. Two set of samples with average carbon content of 40 and 60ppm were subjected to heat treatment at the critical ageing temperatures 200 and 225ºC,
respectively. During the ageing treatment, the cycle was interrupted on several time intervals in order to obtain the core loss and determine the mechanical properties by
means of Vickers hardness. After that, the characterization of the precipitates using scanning electron microscope (SEM) was performed. The results for both carbon
contents showed that the maximum hardness value was achieved in shorter times than the maximum core loss, indicating that the critical size of precipitates harmful to
the magnetic properties is larger than the ones that maximize hardness. Besides this, for both carbon content the change in the rate of magnetic ageing index as function of
ageing time at critical temperature, has its maximum value at the time necessary for the magnetic ageing index exceed 5%.
José Rogério de Oliveira Júnior
Research Centre, Aperam South America.
Grain-oriented steels, non-oriented electrical
steels high silicon sheets
A mechanical strain occurring during the drilling or punching of a hole on electrical sheets will cause deterioration of the magnetic characteristics around the hole. The
result is that, when the sheet is magnetised parallel to the edge, the magnetic flux density has changed its orientation around the hole [1]. In this study, variation of
localised flux density distribution due to cutting method and frequency around a hole was investigated from the search coils located at 0º, 25º, 45º and 65º angles
Effect of Cutting Method and Frequency on
Localised Flux Density Distribution around a Hole corresponding to the centre of holes with diameters 10 and 20 mm in non-oriented electrical steel sheet with the dimensions of 300 mm length, 30 mm wide and 0.50 mm
thick standard sample. The localised flux density and magnetic field strength were measured over the peak flux density ranges 0.1 - 0.5 T at 50 - 400 Hz. A minimum flux
in Non-Oriented Electrical Steels
density was obtained from the search coil which is located at 65º whereas maximum flux density was measured from the coil located at 0º. [1] T. Gunes, N. Derebasi, C.
Erdonmez, Localized Flux Density Distribution Around a Hole in Non-Oriented Electrical Steels, IEEE Trans. Mag. Vol. 51, Is. 1, 2015.
Naim Derebasi
Department of Physics, Uludag University,
Gorukle Bursa Turkey
Grain-oriented steels, non-oriented electrical
steels high silicon sheets
Electrical steel sheets, which are used in electrical machines are exposed to stresses during cutting operations, and consequently the steel magnetic properties are
deteriorated, in addition, the material microstructure is affected around the cutting area. Several cutting techniques are used in industry, such as shear cutting, punching
and laser cutting. In this paper, the influence of shear cutting on the steel microstructure and magnetic properties was investigated. The Single Sheet Tester (SST) from
Brockhaus measurements was employed for measurements of different grades of non-oriented electrical steel samples with different induction levels (0.1-1.5T) and a wide
range frequency (3 Hz - 1 kHz). A scanning electron microscope (SEM) and Electron Backscatter Diffraction (EBSD) were used for characterization of the microstructure
(grain size and texture) at the cutting edges. The mechanical properties like hardness and elastic modulus at the edge were explored using nanoindentation. The novelty of
this work can be seen through the comprehensive study of the material properties from material science point of view to explain the change of magnetic properties of the
material. A better understanding of the effect of induced stress on magnetic properties will help in material development and improve the electrical machine design
process.
Aroba Saleem
McGill University
Grain-oriented steels, non-oriented electrical
steels high silicon sheets
Grain-oriented steels, non-oriented electrical
steels high silicon sheets
Grain-oriented steels, non-oriented electrical
steels high silicon sheets
Grain-oriented steels, non-oriented electrical
steels high silicon sheets
Title
EFFECT OF SHEAR CUTTING ON
MICROSTRUCTURE AND MAGNETIC PROPERTIES
OF NON ORIENTED ELECTRICAL STEEL
EFFECT OF SHEAR DEFORMATION TEXTURE IN
HOT STRIP ON TEXTURE AND MAGNETIC FLUX
DENSITY OF NON-ORIENTED ELECTRICAL STEEL
In recent years, the demand for hybrid electrical vehicles (HEV) has been increasing in terms of energy saving. Downsizing in traction motors of HEV is required to reduce
the space and energy consumption due to weight reduction. Therefore, increasing magnetic flux density (B50) of core material, non-oriented electrical steel sheets (NO), is
absolutely necessary to realize small high torque traction motors. B50 is enhanced by decreasing {111} or increasing {110}(Goss) or {100}(Cube). B50 has been improved by
texture evolution of NO to change the process conditions in hot band annealing, cold rolling (CR), and primary recrystallization annealing. However, effect of texture
generated by the shear deformation during hot-rolling (shear deformation texture) has not been investigated. To clarify the effect of shear deformation texture on B50, two
specimens were prepared: the surface layer of hot strip by removing the other side with mechanical grinding, and center layer of hot strip by removing the both sides. One
direction or cross direction CR and annealing was applied to the both specimens, and the textures and B50 of the specimens were examined. Experimental results shows
that shear deformation texture suppresses {111} and enhances Goss in case of one direction CR, and enhances {411} near to Cube in case of cross CR, which means that
increasing intensity of shear deformation texture is novel method to enhance B50 and increase torque of motor.
Takeru Ichie
Nippon Steel & Sumitomo Metal Corporation
Effect of the interdependence of cold-rolling
strategies and subsequent shear cutting on the
magnetic properties of electrical steel sheets
Non-grain-oriented electrical steels are major components of rotating electrical machines. The high silicon content of such steels results in a ferrite microstructure over the
complete manufacturing process. Therefore, the whole process chain has an impact on the microstructure evolution e.g. grain size and texture which determine the
electromagnetic properties. Thus, it is of interest to optimize the complete manufacturing process towards lower iron-loss or other physical properties. In this paper, the
effect of different cold-rolling strategies, annealing treatments as well as sheet metal blanking is studied regarding the microstructure evolution and resulting
electromagnetic properties. Hot-band samples are cold-rolled and annealed differently in order to produce distinct samples of electrical steel sheets of the same thickness.
Then the magnetic and microstructural properties of the different sheets are analyzed. The samples are processed afterwards in order to study the deterioration of the
magnetic properties after shear cutting. Comparative measurements of the altered samples are conducted and analyzed. The full paper will present the experimental setup
in detail. Characteristic parameters which describe the cold-rolling strategies, the annealing process and the subsequent shear cutting process will be presented.
Measurement data will be given and analyzed for the connection between the production process and the magnetic properties.
Thorsten Kurpat
Institut of Electrical Machines (IEM), RWTH
Aachen University
Effect of thickness on the excess losses of
deformed electrical steels
Loss separation is a valuable tool for characterization of electrical steels. In the present study, three non-oriented electrical steels with different thickness were
investigated, 0.60, 0.66 and 0.90 mm. All three steels have similar chemical composition. The steels were submitted to a 5% skin pass. The loss separation divides the losses
in three parts, according how these parts vary upon the frequency (f): eddy (f^2), hysteresis (f^1), excess (f^3/2), There is doubt concerning how the excess loss is affected
by thickness. It has been found that deformed steels present almost null excess loss. Thus, deformed steels may give insight on the question of the thicknesses effect. It is
expected that, if eddy currents affect excess losses, the thickness should have effect on that part.
Marcos Flavio de Campos
UFF
Electroless plating: A versatile technique to
deposit coatings on electrical steel
Coatings on grain-oriented electrical steel (GOES) are produced primarily with sol-gel method by depositing aluminium ortho phosphate on top of forsterite. Electroless
deposition of nickel and cobalt based coatings could be used as an alternative to the conventional coatings because stress can be generated and tailored in these coatings.
The rate of deposition in electroless plating is faster as compared to other chemical coating techniques and the process is auto catalytic (no external current required). The
coatings are corrosion, wear and abrasion resistant and the magnetic properties of the coatings could be varied by simply changing the pH of the solution. Addition of
alloying elements like phosphorus and boron significantly affect the final properties. A 2.15 ± 0.15 µm thick Co-Ni-P coating on GOES was able to reduce the power loss by 911 % and shift the magnetostriction curve towards the left by 1.8 ± 0.2 MPa. The reduction in power loss and magnetostriction was due to applied compressive stress by
the coating on GOES. Similarly a 414 ± 40 nm thick coating of Co-P-CNT on GOES was able to reduce the power losses ranging 13-15%. The resistivity of the coating was
measured to be 104 µΩcm which reduce the eddy current loss. An improvement in the surface roughness after coating the samples with electroless plating contributed to
reduction of hysteresis loss and hence bringing down the overall loss.
Vishu goel
wolfson centre for magnetics, cardiff university,
cardiff, UK
Grain-oriented steels, non-oriented electrical
steels high silicon sheets
Evaluation of formaldehyde release from ASTM
C6 coating of non-oriented electrical steel
A methodology was developed to measure formaldehyde released from ASTM C6 (A976) coating of non-oriented grain (NOG) electrical steel. There are standards for
evaluating formaldehyde release from several products, such as wood panels. But no standard was found in the literature regarding to steel products. The C6 varnishes are
applied as insulation of the stator core NOG sheets and they are based on melamine or phenolic resins, which contains precursors of formaldehyde used as crosslinking
agents. The component is released during and after the curing process, which can be harmful to humans and, at very high concentrations, it is correlated with cancer.
Therefore, manufacturers of large rotating electrical machines are concerned about any potential formaldehyde release during the operation. In addition, they are
supporting the development of new formaldehyde-free varnishes. A methodology was developed for the determination of formaldehyde emissions of NOG coated sheets
based on the desiccator method. The formaldehyde released at temperatures of 60, 80 and 120°C from the cured coatings was measured by ultraviolet-visible
spectroscopy using the colorimetric method with acetylacetone. It was observed an increase in the formaldehyde release by increasing the temperature. In addition, the
effect of the curing conditions in the stability of the varnish film was evaluated by thermal analysis, which showed that the thermal performance of the product is
dependent on these parameters.
Carolina Cesconetto Silveira
Research Center, Aperam South America, Brazil
Grain-oriented steels, non-oriented electrical
steels high silicon sheets
The magnetic properties of Fe-Si steels critically depend on the microstructure, especially grain size, and texture components. It appears that the evolution of the grain size
and texture is effected sensitively on the microstructure and texture along the different processing steps: casting and hot rolling, thermal treatment after hot rolling or of
Evolution and Interaction of the Microstructure the hot band, cold rolling and annealing. Optimum grain size is obtained at final annealing at higher temperatures to due grain growth. While large grain size after final
and Texture at the Different Processing Steps for annealing is prefareable for low magnetic losses, the texture components of the hot band appears as a key factor for optimal magnetization behaviour of the finally
proecessed material. Texture intensities is mainly influenced by the stored deformation energy and grain boundary mobility. For this reason a deeper understanding of the
Ferritic Nonoriented Electrical Steels
evolution of the microstructure and texture along the processing steps and their modelling are desirable. In this paper, we will summarize our recent results on the
evolution of microstructure and texture along the processing route. Thereby the thin strip casting and the conventional processing route are regarded.
Jürgen Schneider
Institute of Metal Forming, TU Bergakademie
Freiberg
Grain-oriented steels, non-oriented electrical
steels high silicon sheets
It is well known that Silicon content up to 6.5 wt. % gives excellent magnetic properties such as high saturation magnetization, near zero magnetostriction for the FeSi
electrical steels. But their workability is reduced by the appearance of ordered structures, namely B2 and DO3, when the Si content becomes higher than 3.5 wt. %. The
positron annihilation lifetime technique (PALT) and the optical microscopy (OM) are used in this work to investigate FeSi samples with 7.5 wt.% Si. The samples are
subjected to different degrees of deformation. The isochronal annealed samples are measured using the PALT to investigate the types of defects exists during the annealing
process. The PALT Data shows that the positron annihilation mean lifetime (τmean) decreases for all alloys with the increase of the annealing temperature. This is
attributed to a decrease of the concentration of defects which is believed to dislocations according to the positron annihilation lifetime values. But at 600°C there was a
sudden increase of the τmean for all samples This could be attributed to the change of the ordering of the FeSi alloys and believed to be related to the existence of vacancy
clusters. Starting from 900°C, they became constant. The microstructures of the alloys, investigated by OM, show that recovery process and recrystallization are completed
at 900°C and the samples are almost free of defects. The value for the positron annihilation lifetime at 900°C is calculated to be
Khaled M Mostafa
1 Department of materials science and
engineering, Ghent University- Technologiepark
903, 9052 Ghent- Zwijnaarde, Belgium. 2
Department of physics and astronomy, Ghent
University, Proeftuinstraat 86, 9000 Ghent,
Belgium
Grain-oriented steels, non-oriented electrical
steels high silicon sheets
Grain-oriented steels, non-oriented electrical
steels high silicon sheets
Grain-oriented steels, non-oriented electrical
steels high silicon sheets
Grain-oriented steels, non-oriented electrical
steels high silicon sheets
Formation of vacancy clusters during the
annealing of deformed FeSi alloys.
Grain-oriented steels, non-oriented electrical
steels high silicon sheets
GOSS texture formation by solute dragging in
grain oriented silicon steel
The possibility of abnormal grain growth in Fe-3%Si steel by solute dragging was investigated. It is well known that the formation of GOSS texture in grain oriented silicon
steel needs precipitates enough to inhibit the grain growth during annealing. We have thought that precipitates would be replaceable by solutes as long as the srgregated
solute reduce the grain boundary energy. The driving force of grain growth will be decreased by reducing the grain boundary energy. We also have tried to find out
effective solutes strong enough to drag the grain boundary movement during high temperature annealing. Several elements were selected in view of the energy difference
between matrix and solute atoms. As a result, abnormal grain growth was sucessfully achived without precipitates after secondary recrystallization annealing. The
abnormally grown grains were confirmed to have the GOSS orientation. And, its magnetic properties are good enough, because of the sharp GOSS texture formation We
will discuss what kinds of element are available to achive strong GOSS texture and how to process to obtain it.
Hyung-Don Joo
Technical research laboratories, POSCO
Improvement of magnetic properties and
crystallographic texture of NO silicon steels by
thermal processing in high magnetic field
Non-oriented electrical steels belong to important group of the soft magnetic materials that are typically used as core parts in a variety of electrical rotating equipments.
Their good soft magnetic characteristics strongly rely on the ability to control the grain size and crystallographic texture as well as chemistry of the final steel sheets
products. The most appropriate texture for NO steels is so-called "rotating cube" with the easy magnetization directioc (100), which provides isotropic magnetic properties
in all plane directions of sheet steels. In this work, we report on the effects high static magnetic field on the formation of desirable crystallographic orientation of grains
(rotation cube or Goss) during the primary recrystallization of NO steels. Vacuum degassed NO steel with the silicon content about 1% wt. was taken from industrial line
after final cold rolling with 80% of deformation and then it was subjected to the laboratory annealing at the temperature of primary recrystallization. Whole annealing
process was carried in external magnetic field of 14T. The analysis of crystallographic orientation of experimental material was studied by EBSD technique. The magnetic
measurements show that the coercivity value of the samples annealed in the magnetic field of 14 T were reduced by approx. 10% in comparison with samples annealed
under zero field conditions.
Ivan Petryshynets
Institute of Materials Research, Slovak Academy
of Sciences, Watsonova 47, 04 001 Kosice,
Slovakia
Grain-oriented steels, non-oriented electrical
steels high silicon sheets
Improvement of magnetic properties of a
reversible hot rolled GOES
The obtaining of excellence in magnetic properties of grain oriented silicon steel processed via Steckel mill has represented a challenge to Aperam. Due to the
characteristics of this process, with larger susceptibility to temperature variation, and consequently, variation of properties along the length, a precise control of the
process and product parameters is required. This paper will focus on the effect of hot rolling temperature and chemical composition, specifically the carbon content and
Mn/S ratio, on the behavior of manganese sulfide precipitation. The process data evaluation identified that an adjustment in the range of hot rolling temperature could
contribute to reduce the observed occurrence of variation in magnetic loss, concentrated in regions near of the head of the strip that appears like a bulge at core loss
charts. PTT curves were raised considering the typical chemical composition to this steel, based on literature and experimental models, and comparison with current
practices was done. Experiments were carried out at the plant, seeking the temperature setting, which the rolling process started within the range of sulfide precipitation,
following the theoretical prediction. The results of the first tests have already indicated a trend of decline in the occurrence of the phenomenon mentioned. Additional
chemical composition and process adjustments were taken to guarantee stabilization of magnetic properties along the length.
Marcos Custódio Guimarães
APERAM S.A.
Grain-oriented steels, non-oriented electrical
steels high silicon sheets
In situ observation of recrystallizing texture in non-oriented electrical steel was investigated using heating stage in the SEM. The specimen was hot rolled to form 2.3 mm
thick sheet and then cold-rolled to 0.5, 0.35 and 0.1 mm, which corresponds to reduction ratios of 78%, 85% and 96% respectively. Chemical composition of the steel used
in the present study is as follows: 2.8 Si, 0.1 Mn, and 0.5 Al in weight percent with a balance of Fe. The in-situ heating was carried out in a stepwise way. The specimens
In situ EBSD observations of recrystallizing texture were annealed at 700 , 720 , 740 , 800 , and 850 for 10 seconds at 10-3 Pa vacuum. Electron backscatter diffraction (EBSD) measurement were followed at 300
with varying reduction ratio in non-oriented
degree below the annealing temperature to avoid texture change during the measurement. Nucleation on the deformed //ND texture is slow. However, the size of the
electrical steel
grains becomes larger, because of the fast grain growth on the deformed //ND texture. The grain growth of other grains mainly occur after the recrystallization of the
deformed texture is completed. The average grain size decreases with increasing reduction ratio. During the early stage of recrystallization, the Goss texture component is
weakened markedly with increasing reduction, the {111} texture component is strengthened. The cube orientation also lessens with increasing reduction. Nevertheless,
recrystallized //ND texture is getting stronger with a high reduction ratio.
H. Mun
Graduate Institute of Ferrous Technology (GIFT),
Pohang University of Science and Technology
(POSTECH), Pohang 790-784, Republic of Korea
Influence of Hole Geometry and Induction
Frequency on Flux Density in Non-Oriented
Electrical Steels
A mechanical strain caused by shearing, drilling and punching stresses, occurring during the process of electrical steel sheets, will cause deterioration of the magnetic
characteristics of the sheet. One result is that, when magnetised parallel to the cut edge of a sheet the magnetic flux density measured in the cut-edge region is less than
the flux density at the centre of the sample. The deterioration of magnetic properties can be deduced from a study of the change in the flux density distribution due to
mechanical process. The flux density distribution due to cut-edge stress was previously investigated by some researchers [1]. In this study, the variation of localised flux
density distribution is measured and monitored from a search coil located at 45º angle corresponding to the centre of different hole structure such as circular, ellipse,
rhombus and square. The localised flux density and magnetic field strength in conventional and water jet cut non-oriented electrical steels were measured over the peak
flux density ranges 0.1 - 0.5 T at 50 - 400 Hz. A minimum flux density was obtained from the sample which has an circular hole at the same field strength level for all
frequencies measured whereas maximum flux density was measured from the sample which has a ellipsoidal hole. More result will be presented. References [1] A.J. Moses,
N. Derebasi, G. Loisos, A. Schoppa, Aspects of the cut-edge effect stress on the power loss and flux density distribution in electrical steel sheets, Journal of Magnetism and
Magnetic Materials, Vol. 215 - 216, (2000), pp. 690 - 692.
Naim Derebasi
Department of Physics, Uludag University,
Gorukle Bursa Turkey
Grain-oriented steels, non-oriented electrical
steels high silicon sheets
Loss dependance on magnetic field direction in
NO Silicon steels : Correlation with texture
Electrical machine and their cooling system are designed as compact as possible. In this context, iron losses should be estimated accurately since they are of paramount
importance. The stator Iron Silicon sheets are cut in one piece so the angle between the RD and the preferential direction of the flux changes from one tooth pitch to
another. It seems important to get an overview of the loss variation on a continuum of directions in relation with the texture Pole figures deduced from EBSD analysis show
that grains of sample 1 (0.35mm thick) are mainly oriented on the (110) plane with a dispersion of the axis between RD and TD. Sample 2 (0.2mm thick) anisotropy is more
pronounced. Indeed, a thicker sample needs at list one more rolling pass, until the deformation occurs on the densest plane, in this case (110) planes are parallel to the
sample plane. The majority of crystals are oriented on the (110) plane and due to the lamination effect there is a preference orientation of axis in the RD. Loss
measurements have been done on the two samples in a continuum of direction [0°, 90°] by step of 5° using a SST2D. Results are in good agreement with texture study and
have shown that the anisotropy of iron loss is more pronounced in sample 2. A peak loss value is recorded between 50° and 60° for the two samples, since hard direction in
a crystal oriented on (110)[001] is about 54,7°. Finally, a third sample which has an isotropic texture will be compared to the first sample
HAMRIT Oussama
SATIE, ENS Cachan, CNRS, Université Paris-Saclay,
61 Av Président Wilson, F-94230 Cachan, France
Grain-oriented steels, non-oriented electrical
steels high silicon sheets
An iron loss increases by the fixation method of a stator core such as swaging, welding and the thermal insert, etc. They make a residual stress in the motor core. It leads to
increase a building factor and an iron loss of the motor. Therefore, the residual stress must be removed or reduced to decrease the iron loss of the rotating machines. It
New Fabrication Method Suggestion of the Motor needs to remove or reduce the fixation method of a stator core for the motor. In this paper, a possibility of the new bonding method using ceramic precursor for motor
Core using ceramic precursor
core was investigated. Oxidized ceramic layer were appeared between each silicon steel sheet. We prepared specimen with 4 layers of 35A270 using new bonding method,
swaging and no bonding. Each iron loss (W10/50[W/kg]) of no bonding, swaging and new bonding method was 0.78, 0.98 and 0.87, relatively. And maximum bonding
strength of new method using tensile shear strength was 2.36 MPa. It must be improved.
Kyyoul YUN
Gifu Univ.
Grain-oriented steels, non-oriented electrical
steels high silicon sheets
Grain-oriented steels, non-oriented electrical
steels high silicon sheets
Grain-oriented steels, non-oriented electrical
steels high silicon sheets
Electrical steel or silicon steel is one of the most important soft magnetic materials, which is 97 % of the materials, due to its high permeability and low coercivity. Electrical
steels are classified into two groups according to its uses: grain-oriented (GO) electrical steels mainly used for cores of large transformers and non-oriented (NO) electrical
steels are adequate for rotating machines. In recent, NO electrical steel has been extensively focused on its application as motor-core of electrical vehicles. Key challenges
in advancing the performance of electrical steel sheet for electric vehicles are high magnetic flux density and low core loss at high frequencies. Low core loss at high
Phosphorus Effects on Slip Band Formation,
Recrystallized Texture and Magnetic Properties in working frequencies can easily achieved by reducing its thickness to 0.1mm, but further improvements are necessary due to low magnetic induction at such an ultra-thin
NO steel. One of the best ways to enhance magnetic induction is to manipulate crystallographic texture of the steel sheets by segregation elements. In this study,
Electrical Steels
crystallographic texture was enhanced by phosphorus. The ultra -thin electrical steels sheets with composition of 3.2wt% Si and 3.2wt% Si-0.1wt% P were prepared by hotrolling, hot-band annealing, cold-rolling and recrystallization. Slip band formation, texture of final recrystallized texture and their magnetic properties were investigated.
The effect of phosphorus on slip band formation during cold rolling and recrystallized texture were observed.
Jaewan Hong
GIFT, POSTECH
Grain-oriented steels, non-oriented electrical
steels high silicon sheets
The stresses and strains generated in the punching process of electrical steel laminations are known to degenerate the magnetic properties in the region near the cut edge.
Existing work has tended to focus on strips, with estimates for the damaged width ranging from less than 1mm up to 10mm. This work has considered ring samples which
are more representative of motor laminations. Decreasing the width of the samples and therefore increasing the proportion damaged by the punching allowed the creation
of mathematical models to describe and analyse the power loss and estimate the width of the damaged region. Samples measuring 5 laminates high with a constant outer
Power loss models in non-oriented electrical steel
diameter of 200mm and various inner diameters (160mm, 170mm, 180mm, 190mm) were stamped from coils of M250-35A and M330-35A of non-oriented electrical steel.
rings after punching
A simple model was initially proposed where power loss is proportional to the ratio of the undamaged to the total width and the square of the flux density passing through
that region. Average distances for the damaged region were calculated at 0.64 mm for M250-35A and 0.66 mm for the M330-35A. Loss separation analysis performed on
the same samples demonstrated that hysteresis loss was dominant up to a point where the product of frequency and induction is, fB ≈ 375 T/s after which the eddy current
loss was the dominating factor.
Nicholas Lewis
Cardiff University
Grain-oriented steels, non-oriented electrical
steels high silicon sheets
Precise Computation Method of Magnetic Loss
Considering Blanking Press Strain : A Study of
Actual Measurement Method of Blanking Strain
Distribution in Electromagnetic Steel Sheet
The manufacturing process of motor cores made from electromagnetic steel sheets is generally adopted processing methods with a high regard for mass productivity, such
as blanking, caulking, and shrink fit. These process which involve the residual stress and strain (processing stress) which make the magnetic domain movement difficult in
the material cause the iron loss to increase. However, in the conventional motor loss analysis, there has been no method to accurately estimate the effects of the
processing stress. Therefore, in the productization of compact high-efficiency motors which are sensitive to processing stress, there are problems that the development
cost increases by trial and error and it's difficult to design optimally motors. Recently, the iron loss simulation method considering the punching strain have been studied,
but the strain distribution of the thin steel sheet material which is difficult to actually measured relies on the structure analysis simulation. For this reason, the validity of
the finally obtained magnetic loss was debatable. So this paper examined the actual measurement method of the blanking strain in the magnetic electromagnetic steel
sheet, and we showed the strain distribution by using the neutron diffraction. We will examine the modeling method of iron loss estimation based on the result in detail.
Satoshi Doi
DENSO Co. , Doshisha University
The effect of the strain rate on cleavage fracture
in Fe−Si−Al alloys
Iron−silicon steels have excellent magnetic and electrical properties, especially, with increasing silicon content. However, this reduces the workability of the material, and
spontaneous cleavage fracture may occur during production. The materials investigated are alloys with 2 or 3 wt.% Si and 2 wt.% Al. Conventional fracture mechanics tests
at room temperature and −20°C give surprisingly high values of the fracture toughness Kc. An increase of the loading rate by a factor 10 does not influence significantly the
Kc-values. Interestingly, confined cleavage fracture regions can be found in the pre-fatigue regions of the specimens, although the maximum stress intensity Kmax during
pre-fatigue is much lower than Kc. In order to resolve this effect, fatigue experiments are performed at various frequencies. The strain rates during the various fatigue- and
fracture experiments are estimated. The analysis reveals a significant strain rate dependency of the stress intensity at the onset of cleavage fracture.
Andreas Umgeher
Erich-Schmid-Institute of Materials Science,
Austrian Academy of Sciences, Jahnstraße 12,
8700 Leoben, Austria and Materials Center
Leoben Forschung GmbH, Roseggerstraße 12,
8700 Leoben, Austria
E-mobility - New Challenges for the material
electrical steel strip
Non-grain-oriented electrical steel is the preferred material for electrical drives in cars and trucks. The special requirements are high r.p.m. and therefore high frequencies
in the magnetic core. Extra thin, high silicon/aluminium Ðalloyed electrical steel reduces the core losses at high frequencies and allows highly efficient electrical drives at
low losses to be produced. The impact of the further processing of electrical steel as well as the development of two connecting technologies, such as laser welding and
glueing with Bonding-varnish will be presented.
Norbert Brachthaeuser
C.D. Waelzholz
Grain-oriented steels, non-oriented electrical
steels high silicon sheets
Grain-oriented steels, non-oriented electrical
steels high silicon sheets