Electrical Steel Research Articles

Sifat-sifat Fizikal, Kimia dan Morfologi Tanah Laterit di Daerah Bandar Baharu, Kedah

Bandar Baharu District in southern of Kedah, Malaysia is extremely rich in laterite soil. The district is distinguished by the widespread presence of laterite soil, making it critical to thoroughly explore its physical, chemical, and morphological properties. Understanding these properties is essential for determining the acceptability and behaviour of laterite soil in a variety of engineering and building applications. Thus, the objective of this study is to analyze and evaluate the physical, chemical, and morphological properties of the selected laterite soil. Three sources of laterite soils have been identified in Sungai Kechil, Bandar Baharu, and Relau. The samples are labeled as SS-A, SS-B, and SS-C. The soils are categorized as SM, SC and MH respectively according to classification by Unified Soil Classification System (USCS). Since the pH values were less than 6, all of the soils were acidic. The X-ray fluorescence (XRF) characterization shows that the three soil samples have three main chemical components, namely silicon dioxide (SiO<sub>2</sub>), aluminium oxide (Al<sub>2</sub>O<sub>3</sub>) and iron oxide (Fe<sub>2</sub>O<sub>3</sub>). According to the X-Ray diffraction analysis (XRD) results, the minerals discovered in the laterite soils were gibbsite, quartz, kaolinite, and magnetite. Based on the scanning electron microscope (SEM) image, the sample with the highest fine particle content, which is 55.7% for the SS-C sample, shows the smallest pore size.

A ROLL’S WEAR DURING HOT ROLLING OF HIGH-SILICONSTEEL AND ITS IMPACT ON THE QUALITY OF A STRIP’SPROFILE

Hot rolling of grain-oriented high silicon steel is related to technical problems such as high temperature andlong rolling campaigns with strips of the same width. Numerous methods may be carried out as a solutionto these problems. Before the rolling campaign, all rolls of finishing stands are exchanged. The campaign isscheduled with additional exchanges of rolls on two last stands in two stages. A roll’s wear increases with thequantity of rolled material and may lead to strip profile deformation. Exchanging the rolls ensures the requiredsteel quality and prevents losses caused by quality defects. This work identifies factors affecting the workroll's wear and refers to the material from which rolls are made. This work aimed to determine the wear ofwork rolls of the finishing group rolling mills during the rolling of high-silicon steel. The work presents wearanalyses of 30 rolls. It was analysed depending on roll type and high silicon steel rolled material quantity.Compared wear of rolls after rolling high-silicon steel and black sheet. By analysing the distribution of rollwear along the length of the roll, it was found that the wear of working rolls directly affects the geometry ofthe rolled sheet, which may affect the quality of the strip profile of the rolled sheet.

Development of Reference Materials for AC Magnetic Properties of Cold-rolled Non-oriented Electrical Steel

Electrical steel is a soft magnetic material used in the manufacture of various electrical equipment intended for the transmission and conversion of electricity and used mainly in alternating magnetic fields of industrial frequencies. The key properties of such a material are AC magnetic properties, which are standardized when assessing the compliance of the material with the requirements of both Russian and foreign standards. The article presents information about the aspects of the development of reference materials for AC magnetic properties of electrical cold-rolled non-oriented steel made in the form of strips for the Epstein frame. The main feature of these reference materials is that the value of one of the two certified characteristics (specific power of magnetic losses) is transmitted directly from the State primary standard, and the other (magnetic induction amplitude) is determined in accordance with a certified measurement procedure. Their use will provide the possibility of a comprehensive and reliable determination of the magnetic characteristics of samples of non-oriented electrical steel normalized in accordance with the requirements of current standards.

Choosing the best magnetostrictive material for energy harvesting applications: A simple criterion based on Ericsson cycles

The best magnetostrictive material for energy harvesting applications is not necessarily the material with the highest magnetostriction strain. In this paper, based on the description of the Ericsson cycle, a simple criterion to define the most efficient material is proposed. The criterion takes into account the accessible range of stress and magnetic field. It relies on four material parameters only, namely the initial magnetic susceptibility, the saturation magnetisation, the maximum magnetostriction strain and the coercive field of the considered magnetostrictive material. Mass density and price are also involved if a weight optimisation or a cost optimisation is sought. The potential of several materials is compared based on this approach, and it is shown that Giant Magnetostrictive Materials are not systematically the best choice for energy harvesting applications, challenged for some operating conditions by electrical steels.

Diffusion of Alloying Cobalt Oxide (II, III) into Electrical Steel.

This paper aims to reduce power loss in electrical steel by improving its surface resistivity. The proposed approach involves introducing additional alloying elements through diffusion once the steel sheet reaches the desired thickness. Various effective techniques have been suggested and tested to enhance the resistivity of the strip. The method entails creating a paste by combining powdered diffusing elements with specific solutions, which are then applied to the steel's surface. After firing the sample, a successful transfer of certain elements to the steel surface is achieved. The amount and distribution of these elements can be controlled by adjusting the paste composition, modifying the firing parameters, and employing subsequent annealing procedures. This study specifically investigates the effectiveness of incorporating cobalt oxide (II, III) into non-oriented silicon iron to mitigate power loss. The experimental samples consist of non-oriented electrical steels with a composition of 2.4 wt% Si-Fe and dimensions of 0.305 mm × 300 mm × 30 mm. Power loss and permeability measurements are conducted using a single strip tester (SST) within a magnetic field range of 0.5 T to 1.7 T. These measurements are performed using an AC magnetic properties measurement system under controlled sinusoidal conditions at various frequencies. The research explores the impact of cobalt oxide (II, III) addition, observing successful diffusion into the steel through the utilization of a paste based on sodium silicate solution. This treatment results in a significant reduction in power loss in the non-oriented material, with power loss reductions of 14% at 400 Hz and 23% at 1 kHz attributed to the elimination of a porous layer containing a high concentration of the diffusing element. The formation of porosity in the cobalt addition was found to be particularly sensitive to firing temperature near the melting point. The diffusion process was examined through scanning electron microscopy (SEM) in combination with energy-dispersive X-ray spectroscopy (EDS). The results demonstrate improved power losses in the coated samples compared with the uncoated ones. In conclusion, this study establishes that the properties of non-oriented electrical steels can be enhanced through a safer process compared with the methods employed by previous researchers.

Development of FeSi steel with increased Si content by laser powder bed fusion technology for ferromagnetic cores application: Microstructure and properties

Additive manufacturing technology like laser powder bed fusion represents a valid alternative for the production of ferromagnetic cores. In this study, two grades of steel were considered, with standard (3.0 wt%) and high (6.5 wt%) Si content. The study is aimed at optimizing the process parameters in order to obtain components suitable for magnetic applications. Moreover, the effect of post-production annealing heat treatment on the microstructure evolution is investigated. The investigation included microstructural analysis by optical microscope, dynamic scanning calorimetry analysis and electro-magnetic measurements on samples with optimized geometry. Results shows that both types of steel can be produced free from defects. Even if the magnetic behaviour of FeSi6.5 samples by AM do not fully reproduces that obtained on electrical steels manufactured by standard process, it appears quite promising. In this framework the optimization of post-production processes represents a promising challenge to meet market demands.Graphical abstract

Analysis of the Vibration Characteristics and Vibration Reduction Methods of Iron Core Reactor

Series iron core reactors are one of the most commonly used electrical equipments in power systems, which can limit short-circuit currents and suppress harmonic waves from capacitor banks. However, the vibration of the reactor will not only generate noise pollution but also diminish the service life of the reactor and jeopardize power system safety. In order to reduce the vibration noise in the core disc region of the reactor, the vibration characteristics of a core reactor are calculated by modifying the anisotropy parameters of the Young’s modulus of the core disc lamellar structure and introducing the core magnetostriction effect based on the simulation analysis method of electromagnetic and mechanical coupling. A detachable single-phase series core reactor model is established, and the validity of the simulation calculation is measured and verified. At the same time, from the perspective of improving the air gap size of the series core reactor and the arrangement of electrical steel sheets, the corresponding iron core vibration reduction scheme is given. The average vibration reduction in the reactor is about 11.6% after comprehensive improvement according to the vibration reduction scheme, which provides an effective method for realizing the vibration and noise reduction in the reactor.

Research on Secondary Recrystallization Mechanism of Oriented Silicon Steel

Based on the understanding that the essence of secondary recrystallization of Goss texture is to restrain the abnormal growth of {110}<112>, {210}<001> and partial Goss texture {110}<225>, it was concluded that making sharp Goss grow up becomes the only choice. It was proposed that the abnormal growth mechanism of Goss texture was the result of selective generation, directed inheritance, and selective growth. The mechanism explained that the Goss texture was the most easily formed shear texture. In directed inheritance, the Goss texture was required to be highly compatible with the near-constant of the second-phase particle inhibition force, providing an optimal environment for the abnormal growth of the Goss texture by controlling the inhibition force near-constant. The control of the near-constant inhibition force provides an optimal environment for the abnormal growth of the Goss texture. Based on that, the process technology for producing low-temperature nitrided-oriented silicon steels and steel products was successfully developed.

Numerical modeling of multipoint blanking process of electrical steel

AbstractA new method of forming using multipoint blanking, which can reduce cutting forces was discussed. In the processes of punching and blanking magnetic materials, an important problem is excessive and irregular wear of the cutting edges of the punches. The contribution proposes multipoint initiated punching using specially designed punches, which aims to significantly reduce the punching forces needed to separate the material. The FEM method was used to analyze the physical phenomena occurring during the process. The updated Lagrange description was used to describe the phenomena at a typical incremental step. The states of strain and strain rate are described by nonlinear relationships without linearization. The description of the nonlinearity of the material was made with an incremental model taking into account the influence of the history of strain and the strain rate. The condition of the material after the previous treatments was also taken into account by introducing the initial states: displacements, stresses, strains, and their velocities. Analyses of the impact of the geometry of blanking tools on the values of stresses, deformations, and blanking forces were carried out. Fatigue analyses were carried out for the proposed tools. The research results may be useful for the design of modern blanking tools used in the processing of electrical materials.

Research Regarding the Dimensional Precision of Electrical Steel Strips Machined by Waterjet Cutting in Multilayer Packages

Manufacturing parts made of thin steel in small batches is a challenging task in terms of reaching the proper balance between the productivity, the cost, and the dimensional precision. This paper presents the results of experimental research about manufacturing electrical steel thin parts using abrasive waterjet cutting. For a certain increase of productivity and a more efficient process, the parts were cut using multilayer packages of steel strips. The main objective was to analyze the influence of the number of layers on the dimensional precision of parts. Preliminary tests were performed, followed by a full factorial experiment using two independent parameters, the number of layers and the traverse speed. The parts were measured on a noncontact vision measurement machine and mathematical models were determined to predict the parts deviations depending on the independent parameters used. A practical validation of the models was performed. The main conclusion is that the number of layers has a certain influence on the accuracy of dimensions, but this influence can be predicted with a satisfactory level of confidence using mathematical models.

A dynamic hysteresis prediction model of grain-oriented silicon steel sheet under AC-DC hybrid magnetization

Firstly, a new method for parameter identification of inverted Preisach model is proposed to simulate static DC-biasing hysteresis behavior of the grain-oriented (GO) silicon steel sheet by using the measured quasi-static concentric hysteresis loops under DC-biasing magnetization. Then, the dynamic magnetic field intensity related to excess loss is improved by considering the nonlinear relationship between the statistical parameter V0 and the AC peaked magnetic flux density, DC magnetic field intensity as well as frequency. Finally, a dynamic hysteresis model in form of field separation is presented to predict asymmetric hysteresis curves under multi-harmonic and DC-biasing hybrid magnetization. The simulated hysteresis curves as well as losses under different AC-DC hybrid magnetizations are compared with the measured ones, which verifies the accuracy and effectiveness of the proposed method.

Measurement and analysis of magnetic properties under SVPWM excitation for soft magnetic composites (SMCs) and silicon steel

This study developed a system for measuring the magnetic properties of soft magnetic materials under space vector pulse width modulation (SVPWM) excitation, enabling testing at different modulation indexes, frequencies, and carrier frequencies. Two types of soft magnetic materials were tested, and the effects of SVPWM waveform parameters on material loss were analyzed. The results show that the loss of SMCs is higher than that of silicon steel when the max magnetic flux density is close to 1.5 T. In contrast, at the modulation frequencies are 100 Hz and 200 Hz, the loss of SMCs is lower than that of silicon steel. The reliability of the testing system was validated through magnetic characterization of the two materials, providing a reference for their application and preparation.

Magnetically active composites with relatively giant dielectric permittivity

"Magnetically active composites based on silicone rubber, silicone oil, carbonyl microparticles, graphene nanopallets and fabric, as a reinforcing element, are manufactured. For a constant amount of carbonyl iron microparticles and silicone oil, and for different ratios between the amounts of silicone rubber and graphene nanopalets, three composite samples are prepared. Using the plane capacitor method, the relative permittivity of the composites is determined. It is shown that by using graphene nanopallets, composites with giant values of relative dielectric permittivity can be obtained and that the relative dielectric permittivity values are sensitive to the magnetic force induced by the static magnetic field superimposed on the medium-frequency electric field. Using the model of the dipolar magnetic approximation and elements of the theory of dielectrics in medium frequency electric fields, the mechanisms participating in the obtained effects are described."

A Study on the Formation of Fiber Texture in the Subsurface Layer of Hot-Rolled Plate of 3.2%Si Grain-Oriented Steel

During the hot rolling process, inhomogeneity microstructure and variations of texture along the thickness direction of hot-rolled plate were formed through shear deformation and recrystallization. The purpose of this study is to investigate the formation and evolution of fiber texture in hot-rolled plate of grain-oriented silicon steel. The results indicate that, in the surface layer s = 1 of hot-rolled plate, a large number of equiaxed grains are formed under high shear force. Under the surface layer, as shear force gradually decreases along the thickness direction, the grain aspect ratio of recrystallized grains gradually increases along the thickness direction of hot-rolled plate, and the shape of the recrystallized grains formed in the subsurface layer and center layer becomes more irregular along the thickness direction. Under the combination of compressive force and decreasing shear force along the thickness direction, fiber texture composed of dozens of specific orientations (such as {112}<111>, {110}<112>, {213}<364>, {441}<104> and Goss orientations) is formed in the subsurface layer s = 0.5~0.9 and gradually evolves along the thickness direction. Therefore, the formation of Goss texture is a small part of fiber texture and is the result of texture evolution in the subsurface layer s = 0.5~0.9.

Rosen-Type Piezoelectric Transformers Based on 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 Ceramic and Doped with Sb2O3.

In this study, the characteristics in the lead-free piezoelectric ceramic 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 (0.5BZT-0.5BCT) were investigated to assess its potential for Rosen-type piezoelectric transformers. This piezoelectric ceramic has a piezoelectric charge coefficient d33 of 430 pC/N, an electromechanical coupling factor kp of 49%, a dielectric constant εr of 2836, a remnant polarization Pr of 4.98 μC/cm2, and a coercive electric field Ec of 2.41 kV/cm. Sb2O3 was soft doped with 0.05, 0.1, 0.15, and 0.2 mol%, respectively, and exhibited excellent physical properties at 0.1 mol%. Based on this, a piezoelectric transformer was fabricated and measured, and it showed better output characteristics than pure 0.5BZT-0.5BCT. The amplification ratio (Vout/Vin) was optimized based on the device geometry and properties of the piezoelectric material. Moreover, the output characteristics of the Rosen-type piezoelectric transformer were simulated with the PSpice program. Output values of the fabricated and simulated piezoelectric transformers for the r vibrational frequency were compared and analyzed. Accordingly, the step-up amplification ratios Vout/Vin of the fabricated and simulated devices at the vibrational frequency were compared as well. This piezoelectric transformer could replace silicon steel transformers and be used for the creation of black light and for laptop chargers.

Advancements in Electrical Steels: A Comprehensive Review of Microstructure, Loss Analysis, Magnetic Properties, Alloying Elements, and the Influence of Coatings

Electrical steels play a crucial role in modern electrical devices and power systems due to their exceptional magnetic properties. This comprehensive review delves into the advancements in the field of electrical steels, focusing on key aspects such as microstructure, loss analysis, magnetic properties, alloying elements, and the influence of coatings. The microstructural characteristics of electrical steels are explored in relation to their impact on magnetic behaviour and overall performance. Loss analysis techniques are discussed, highlighting the importance of minimizing energy dissipation in applications. The intricate relationship between magnetic properties and material composition, including the role of alloying elements, is examined to elucidate the mechanisms governing magnetic behaviour. Furthermore, the influence of coatings on the performance of electrical steels is investigated, considering both protection against environmental factors and their impact on magnetic properties. Through a comprehensive synthesis of recent research, this review provides valuable insights into the multifaceted nature of electrical steels and sets the stage for further advancements in their design and application.

Properties of Glass-Ceramics Prepared from Industrial Multi-Wastes

Because of their excellent properties, glass-ceramics have been widely developed and applied in many fields, and there are many potential application values to be disseminated. The preparation of glass-ceramics from industrial slag and metallurgical waste provides a new way for the comprehensive utilization of solid waste. Coal gangue is the largest of all kinds of industrial waste slag, while iron tailings and high-carbon ferrochrome slag also occupy a large proportion of China’s industrial solid waste. With cheap industrial solid waste as the main raw material, the production of high-value-added glass-ceramics can reduce pollution, protect the ecological environment, and have good economic and social benefits. Cordierite glass-ceramics were prepared using the sintering method with coal gangue, iron tailings, and high-carbon ferrochrome slag as the main raw materials. Meanwhile, an iron silicon alloy containing chromium was obtained. The heat treatment system of basic glass was determined by differential scanning calorimetry (DSC), and the sintered product was analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). An orthogonal test was used to analyze the effects of the mass of basic glass powder, molding pressure, and holding time on the grain size and crystallinity of the samples. The hardness, acid and alkali resistance, density, and water absorption of the sintered products were determined. The results show that the main crystal phase of the prepared glass-ceramics is cordierite. The optimal combination for the green body is “basic glass powder mass 6 g, molding pressure 35 MPa, holding time 10 min”. The properties of glass-ceramics are good. At the crystallization temperature of 970 °C, the Vickers hardness is up to 866 HV, and the bulk density is up to 2.99 g/cm3. This study may provide a useful reference for the treatment of industrial solid waste.

Selection of the Winding Type of Solid-State Transformers in Terms of Transmitting the Greatest Possible Power in the Frequency Range from 500 Hz to 6000 Hz

Solid-state transformer (SST) is an emerging technology that integrates with transformer power electronics converters and control. The most noticeable advantages of SST are the size and weight reduction compared with low-frequency transformers. Since this device is used in many devices such as smart grids, traction systems, systems with renewable energy sources (RESs) and electric vehicle charging devices, it is important to build a high-efficiency device at a low cost. The article evaluates a medium frequency transformer (SST) operating at a frequency of 500 Hz to 6000 Hz with coils wound with aluminum foil or Litz windings and of a grain-oriented electrical steel (GOES) core. The calculations were made using the 3D field method using the numerical finite element method, and the results were compared with the tests of the real model. The measurement method based on the Fourier analysis of real signals was used for the research.

Effects of WEDM and AWJ cutting methods on induction motor efficiency and total magnetic losses: Experimental design and response surface methodology

In this study, the effect of cutting electrical steel laminations using abrasive water jet (AWJ) and wire electrical discharge machining (WEDM) techniques on 5.5 kW induction motor efficiency (MEfficiency) and total magnetic losses (TLosses) was investigated. After the stator and rotor packages were formed, winding, varnishing and mechanical assembly processes were carried out and the motors were prepared for MEfficiency and TLosses tests according to the IEC 60034-2-1-1A standard. Tests were performed using different frequencies (f) and motor loading rates (MLoad). While burr formation was observed with the effect of plastic deformation on the cutting edge of electrical steels with AWJ, recast layer formation was observed with the effect of heat in WEDM. MEfficiency decreased while TLosses increased due to increasing f and MLoad in both cutting methods. Maximum MEfficiency and minimum TLosses values were measured in WEDM, it was determined that optimum results using Response Surface Methodology (RSM) were measured at f of 50 Hz and MLoad of 100% values in both cutting methods. The statistical effects of f and MLoad on MEfficiency and TLosses were revealed with ANOVA (Analysis of variance). In addition, mathematical models were developed for the prediction of MEfficiency and TLosses.

Cyclic deformation behavior of non-oriented electrical steel sheets

The cyclic deformation behavior of a fully processed, non-oriented electrical steel sheet is investigated in dependence on loading condition and control mode. Therefore, strain- and stress-controlled fatigue tests are performed to determine cyclic deformation curves in the low- and high-cycle fatigue regimes. With symmetric strain control, continuous cyclic hardening occurs, while in asymmetric stress control with non-zero mean stress, pronounced ratcheting takes place. Depending on the loading condition, the material can exhibit a transitional period with cyclic softening. This effect is present at intermediate amplitudes in the yield point region. It emerges as the dislocation movement is initially inhibited, while at higher amplitudes, cyclic hardening occurs from the very beginning. The evolving dislocation structures are characterized by the predominantly planar slip behavior of the alloy.