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In this paper a novel Radial-Axial (RA) Flux Switching Permanent Magnet Generator (FSPMG) is introduced. In contrast to other RA flux machines, a major advantage of this generator is its implementation only by the use of conventional Non-Oriented Electrical Steel Sheets (NOESSs), even though the flux linkage of the novel RA-FSPMG has a three-dimensional (3D) path. Besides that, it benefits from the flux concentration strategy and a passive rotor. A concrete foundation of the novel RA-FSPMG is provided, in which, the 3D-Flux path is described, working principles are discussed, and power-sizing equation is derived. No-load (NL) characteristics and the Full Load (FL) performance of an optimized RA-FSPMG are investigated in contrast to an optimized Double Stator Radial (DSR) FSPMG and an optimized Double Stator Axial (DSA) FSPMG with similar volume, number of Permanent Magnets (PMs), and electrical loading. The results show the competitiveness of the novel RA-FSPMG, in particular, in the output power and the required copper mass. Furthermore, the PM demagnetization possibility and the rotor axial pull force of the optimized RA-FSPMG are investigated, in detail. All discussions are supported by the 3D Finite Element Analysis (3D-FEA) and experimental results.

This paper presents a novel linear generator structure of three-phase tubular staggered transverse flux permanent magnet linear generator (TSTF-PMLG) for wave energy conversion. Compared with conventional TF-PMLGs, the new structure has a simpler magnetic flux path, high mechanical strength, low cogging force and more suitable for lowspeed direct driven situation. In the primary of TSTF-PMLG, a nonuniform teeth steel sheets structure is used and steel sheets of different phases are in different angel so that the groove can be separated by staggered steel sheets in the plane perpendicular to the direction of movement. By the analytical model, the operation principle of the motor is explained. Then through the finite element analysis, the distribution of the main flux and leakage flux, the no-load characteristics and output power of TSTF-PMLG are analyzed in detail. And the influence of the lamination factor on the output characteristics of the TSTF-PMLG is obtained. Subsequently the appropriate design parameters of the TSTF-PMLG are selected. During the TSTF-PMLG processing, the method of mixing silicon steel sheets and fiberglass board is used to limiting the lamination factor. Finially, a prototype of 150W rated power and 79% rated efficiency is presented. And the experimental results verify the theoretical analysis.

High-frequency iron losses caused by the variations of sinusoidal flux density with frequencies ranging from 2.5 kHz to 40 kHz, amplitudes from 1mT to 70mT, and dc-biased magnetic inductions from 0 to 1.62T are measured with the dual-transformer system. Then, a simple frequency-domain model is proposed based on linear fitting and 2D interpolation methods for engineering applications. In addition, another two frequency-domain models respectively considering and neglecting excess losses are investigated and compared for the high-frequency iron loss modeling, which only need low-frequency parameters and contain physical interpretation to the variation of high-frequency iron loss coefficients with frequency, AC flux density amplitude, and dc-biased magnetic induction. The iron losses generated by unipolar and bipolar PWM voltages with different switching frequencies and modulation factors are measured to testify the three models. It is shown that the three models in this paper are more accurate than the previously proposed one for calculating the PWM-induced iron loss by considering the variation of model parameters with dc-biased magnetic induction and AC flux density amplitude, especially when silicon steel sheets reach saturation.

The electromagnetic vibration and noise in motors is mainly induced by electromagnetic forces and magnetostrictive force. The low-frequency force waves have a great influence on the deformation of the motor stator core due to resonance. In this paper, a 2-D electromagnetic-mechanical coupling transient model was built based on the quadratic magnetic domain rotation model, considering the magnetostrictive characteristics of silicon steel sheet and the magnetoelastic coupling of materials. Through numerical simulation calculation and analysis, it was found that low-frequency force waves appeared in the motor stator, and the large amplitudes happened on the single and twice power frequency. The actual experimental measurements were designed in the rotating motor and the transformer to verify this phenomenon. It is concluded that the rotating field or the magnetic path distortion leads to the large amplitude at single-power frequency or rotating field frequency on the electrical equipment.

Permanent magnet (PM) synchronous motors have become excellent alternatives for traditional induction and DC motors in numerous applications in recent years. Therefore, torque density and efficiency improvements in development of PM synchronous motors has become a significant issue. In this study, various PM synchronous motor alternatives are proposed with both non-oriented (NO) and grain-oriented (GO) silicon steel material in the same stator in order to increase the power density and the efficiency. Detailed performance comparison using 2D/3D FEA is completed and a feasible stator design is manufactured. The proposed design with GO material is also compared with a conventional PM motor with a NO stator steel. As a result of the investigations, it is observed that the proposed motor with GO material in the stator have higher torque density and efficiency as opposed to the conventional PM motor.

The armature is an important part affecting the energy conversion efficiency of a reluctance accelerator. In this paper, six kinds of soft magnetic materials are chosen and four structures are designed for the armature. At first, the circuit and magnetic force are theoretically analyzed. Then the armatures with different materials and structures are used in the simulation, and the performances are compared and analyzed. At last, the experiment verifies the theory analysis and simulation design. It is concluded that the saturation flux density and conductivity of the material are the key factors affecting the armature force, and the optimization of armature structure can effectively restrain the eddy current, reduce negative force and improve efficiency. Compared with cutting slits in solid armatures, laminating the sheets radially can reduce the eddy current more efficiently. Although slitting can prevent the eddy current to a certain extent, meanwhile, it will decrease the magnetic force because of the losing of magnetized volume and the surface area. Hence, choosing the high saturation flux density material and making out the armature with radially_laminated sheets will improve the efficiency of the reluctance accelerator. In this paper, the silicon steel radially_laminated armature is a better choice for the armature design of the reluctance accelerator.

This paper employs grain-oriented (GO) silicon steel in an axial-flux permanent magnet (AFPM) machine to improve its torque and efficiency. Rolling direction of the GO material have been studied to ensure the machine’s main magnetic flux passes through the easy magnetization direction. Based on the study of the electromagnetic characteristics of AFPM machine, GO silicon steel is laminated to form a stator according to a certain lamination direction. The torque and efficiency of the proposed machine with GO material shows an increase in comparison with that of the conventional non-oriented (NO) silicon steel machine under identical conditions. In addition, an equivalent magnetic circuit model is established to illustrate little difference of electromagnetic property under no-load condition for the yokeless stator AFPM using two kinds of silicon steel sheet. Furthermore, a AFPM machine with stator yoke is also established to highlight the superiority of GO in the application of the AFPM machine with yokeless stator.

An accurate estimation for the magnetostrictive effect in highly grain-oriented electrical steel sheet (HGO-ESS) is helpful for determining the deformation and vibration originating from magnetostriction during the design stages of electrical equipment such as the motor and power transformer. In this paper, a Preisach-based magnetostriction model for HGO-ESS is proposed to simulate the normal and shear magnetostriction properties under alternating and rotating magnetic fields. In the model, the Everett function databases are constructed and identified by using a set of measured symmetric magnetostriction butterfly loops under different rotating magnetic field conditions. The measurement butterfly loops are measured by a round-type two-dimensional single strain tester (R-2-D-SST). Finally, the simulation data and measurement data under different rotational magnetization conditions are compared to verify the effectiveness of the proposed model.

In addition to the excitation condition, the magnetic properties of electrical steel sheet (ESS) also depend on stress and temperature. This article proposes one systematic measurement method of measuring the vector magnetic properties (VMPs) of ESS. In the proposed method, the coupling effect of temperature and stress are considered. The uniform magnetic field distribution is generated in the measurement area of the specimen using a vertical-type orthogonal double-U shaped yoke. Since the specimen is cross shaped, the mechanical stress can be applied conveniently. The B-probe method and the double compound H-coil method are adopted to measure vector magnetic flux density ( B ) and magnetic field intensity ( H ). Moreover, the vector B-H sensor is assembled into a ceramic frame from within, which can withstand high temperature. A linear actuator can apply tensile or compressive stress along the rolling direction and transverse direction of the specimen. The variable temperature measurement conditions are achieved by a temperature controller and ceramic heating sheets. The stress and temperature dependent VMPs of nongrain oriented ESS and grain-oriented ESS are measured to verify the effectiveness of the proposed measurement method. The change regulation of VMPs with temperature and stress is summarized.

This paper presents the influence of wire electrical discharge machine (WEDM) cutting parameters on the magnetization characteristics of electrical steel. The demand for electrical steel keeps increases because of the high demand of electrical motor and transformers for electric vehicle and smart grid applications. The magnetization characteristics of the laminated steel used in these machines have dominates the performance of these machines. The cuttings methods and cutting parameters have huge role in deciding the magnetization characteristics. In this work, WEDM is used to cut the electrical steel in to small pieces. The cutting parameters such as current, feed rate and on-time of WEDM are varied by keeping two of these parameters fixed and one varied. From the electrical steel sheet, 18 sample small electrical steel pieces are obtained at various cutting parameters of WEDM. The magnetic field – magnetization characteristics are obtained using vibrating sample magnetometer (VSM). This analysis shows that higher current, lower on-time and higher feed rate is providing higher magnetization.

Cube texture contains two easy magnetization directions 〈001〉 parallel to rolling and transverse direction, respectively, which is the most ideal magnetic texture suitable not only for transformers but also for rotating machines. In this study, a strong cube texture with ODF density of 50.73 mrd was successfully obtained by regulating the recrystallized grain orientation using cross-rolling and pulsed electric current, compared to conventional thermal annealing (the average cube texture intensity is ~10 mrd in lots of latest studies). Cross cold rolling process intentionally “created” metastable deformed cube orientation in oriented silicon steel and the specific recrystallization texture rotation path was identified under pulsed electric current in 5 min: {114} →{114} →{114} →{001} →{001} . The cube-oriented grains were induced by pulsed electric current (800 °C) and rapid heating (51.9 °C/s, 750 °C), while the cube grains were observed in the annealed samples at the high temperature (1060 °C). Recrystallized grain size of pulsed samples is about twice that of the annealed sample. This phenomenon is considered that the concurrent effects of electron wind force and Joule heating affected the nucleation, growth and rotation of cube grains by reducing the nuclear barrier, producing higher grain boundary mobility and structural evolution towards a state with lower electrical resistance. This idea of current-controlled texture is worthy of popularization in more materials and the realization of an electromagnetic field to crystal orientation selection is an interesting topic.

Purpose This paper aims to use a history-dependent vector stop hysteresis model incorporated into a two dimensional finite elements (FE) simulation environment to solve the magnetic field problems in electrical machines. The vector stop hysteresis model is valid for representing the anisotropic magnetization characteristics of electrical steel sheets. Comparisons of the simulated results with measurements show that the model is well appropriate for the simulation of electrical machines with alternating, rotating and harmonic magnetic flux densities. Design/methodology/approach The anisotropy of the permeability of an electrical steel sheet can be represented by integrating anhysteretic surfaces into the elastic element of a vector hysteresis stop model. The parameters of the vector stop hysteresis model were identified by minimizing the errors between the simulated results and measurements. In this paper, a damped Newton method is applied to solve the nonlinear problem, which ensures a robust convergence of the finite elements simulation with vector stop hysteresis model. Findings Analyzing the measurements of the electrical steel sheets sample obtained from a rotational single sheet tester shows the importance to consider the anisotropic and saturation behavior of the material. Comparing the calculated and measured data corroborates the hypothesis that the presented energy-based vector stop hysteresis model is able to represent these magnetic properties appropriately. To ensure a unique way of hysteresis loops during finite elements simulation, the memory of the vector stop hysteresis model from last time step is kept unchanged during the Newton iterations. Originality/value The results of this work demonstrates that the presented vector hysteresis stop model allows simulation of vector hysteresis effects of electrical steel sheets in electrical machines with a limited amount of measurements. The essential properties of the electrical steel sheets, such as phase shifts, the anisotropy of magnetizations and the magnetization characteristics by alternating, rotating, harmonic magnetization types, can be accurately represented.

Power transformers are an important asset of power companies. To improve the economic benefits of power companies, it is of great significance to accurately predict the lifecycle cost of each power transformer. Based on the historical operating data on 83 110 kV power transformers, this paper estimates the lifecycle costs of different transformers, and then creates a dataset containing the estimated lifecycle costs and multiple features of the transformers, namely, bid price, transformer capacity, no-load loss, load loss, silicon steel cost, copper wire cost, annual failure frequency (AFF) of major repair, and AFF of minor repair. Based on the dataset, a lifecycle cost prediction model was established for power transformers, which couples grey wolf optimization (GWO) with support vector regression (SVR). The GWO-SVR model was simulated on the prepared dataset. The results show that the mean absolute percentage error (MAPE) of the model was merely 5.20% on the test set. The proposed model provides a new method for power companies to accurately predict and evaluate the lifecycle cost of power transformers.

The numerical modeling of magnetic materials in simulators is a difficult task, above all in real devices with specific excitation. The aim of this work is to compare the accuracy of scalar and vector Preisach models in a well know test benchmark: the TEAM 32 problem. The availability of measured data for this benchmark test and the simple geometry allow us to build hysteresis models and to test them in a 2D finite element analysis (FEA) scheme. The specific numerical formulation of each hysteresis model implemented is described, including the technique for the numerical identification of parameters starting from measured data. The comparison among the models is done in terms of accuracy, but also in terms of easy implementation in the FEA scheme and of computational cost.

This study sought to experimentally develop guidelines for shaping 0.3-mm-thick cold-rolled grain-oriented ET 110-30LS steel using a shear-slitting operation. Coated and non-coated steel was used for the analysis. The coated sheet had a thin inorganic C-5 coating on both sides applied to the C-2 substrate. The first part of this paper presents an analysis of the quality of the cut surface depending on the adopted machining parameters, which were the control variables on the production lines. The second part presents an analysis of the magnetic parameters of the cut samples, which allowed for the specific impact of the quality of the cut edge on the selected magnetic features. Finally, an optimization task was developed to obtain a set of acceptable solutions on the plane of controllable process variables such as slitting speed and horizontal clearance. The obtained results can be used to control the shear-slitting process on production lines and obtain high-quality workpieces.

The droplet solidification technique was used to investigate the formation of deposited film and the interfacial heat transfer for the sub-rapid solidification of silicon steels. The composition of deposited films consists of MnO, FeO and SiO2 for both the low and high-silicon steels. The deposited film could improve the wetting condition between the steel droplet and substrate. And the wetting condition between the droplet and substrate improves with the increasing of ejection times from 1 to 9, and thus the final contact angles decrease gradually from 105.1 to 72.8 deg. The peak value of heat flux increases with the number of solidification tests, indicating that the heat transfer condition between the droplet and substrate improves with the deposition of film. The peak value of heat flux increases from 5.64 to 7.42 MW/m2 for low-silicon steel after the 9th ejection, and it is from 6.03 to 9.06 MW/m2 for high-silicon steel. This is because the interfacial thermal resistance between the droplet and substrate reduces gradually with the increasing of test times. A higher Mn content in the high-silicon steel leads to a higher deposited rate of the oxide film than the low-silicon steel. Compared with the low-silicon steel, the increment of MnO content in the film for the high-silicon steel is 6.60 wt pct, and there is no obvious increment of SiO2 in the film, though the increment of Si in high-silicon steel is 6.06 wt pct, and for Mn is only 0.72 wt pct.

Purpose The magnetic characterization of electrical steel is typically examined by measurements under the condition of unidirectional sinusoidal flux density at different magnetization frequencies. A variety of iron loss models were developed and parametrized for these standardized unidirectional iron loss measurements. In the magnetic cross section of rotating electrical machines, the spatial magnetic flux density loci and with them the resulting iron losses vary significantly from these unidirectional cases. For a better recreation of the measured behavior extended iron loss models that consider the effects of rotational magnetization have to be developed and compared to the measured material behavior. The aim of this study is the adaptation, parametrization and validation of an iron loss model considering the spatial flux density loci is presented and validated with measurements of circular and elliptical magnetizations. Design/methodology/approach The proposed iron loss model allows the calculation and separation of the different iron loss components based on the measured iron loss for different spatial magnetization loci. The separation is performed in analogy to the conventional iron loss calculation approach designed for the recreation of the iron losses measured under unidirectional, one-dimensional measurements. The phenomenological behavior for rotating magnetization loci is considered by the formulation of the different iron loss components as a function of the maximum magnetic flux density Bm, axis ratio fAx, angle to the rolling direction (RD) θ and magnetization frequency f. Findings The proposed formulation for the calculation of rotating iron loss is able to recreate the complicated interdependencies between the different iron loss components and the respective spatial magnetic flux loci. The model can be easily implemented in the finite element analysis of rotating electrical machines, leading to good agreement between the theoretically expected behavior and the actual output of the iron loss calculation at different geometric locations in the magnetic cross section of rotating electrical machines. Originality/value Based on conventional one-dimensional iron loss separation approaches and previously performed extensions for rotational magnetization, the terms for the consideration of vectorial unidirectional, elliptical and circular flux density loci are adjusted and compared to the performed rotational measurement. The presented approach for the mathematical formulation of the iron loss model also allows the parametrization of the different iron loss components by unidirectional measurements performed in different directions to the RD on conventional one-dimensional measurement topologies such as the Epstein frames and single sheet testers.

In this paper, three test motors are fabricated with different iron materials, conventional steel, high silicon steel and amorphous iron. Among the three materials, the high silicon steel has the lowest magnetostriction and the amorphous iron has the highest magnetostriction and the lowest saturated flux density. Hammer test is carried out to identify the respective resonant frequency and the optimum Youngs modulus and Poisson ratio are identified from the measured resonant frequency for each core. Furthermore, the acoustic noise is measured in load test and it is found that the high silicon steel has the lowest acoustic noise. Then, the electromagnetic FEA and acoustic noise analysis are carried out. According to the FEA results, the acoustic noise of the amorphous iron motor is the lowest, while it is the highest in an experiment. This discrepancy is considered to be resulted from the magnetostriction property of the magnetic materials that are ignored in FEA so far. Therefore, the magnetostriction of three iron sheets are measured and the FEAs that take magnetostriction into consideration are carried out. From the results of the improved FEAs, it is found that the magnetostriction plays an important role in acoustic noise analysis.

Accurate simulation of the hysteresis loop is challeng-ing, especially using manufacturer data. Traditional parameter extraction methods (e.g., using optimization algorithm and solving transcendental equation) can extract the static Jiles-Atherton (JA) hysteresis model parameters under an arbitrary condition, but it requires fitting parameters because the model parameters vary with flux density. To reduce the dependence on measurement data, this paper proposes a simple but effective parameter extraction method. Firstly, an identification procedure of minor loop is presented using only static B - P loss curves by investigating the influence of model parameters on hysteresis loop, where the average root-mean-square error of the hysteresis loop is decreased by 4. To estimate the dynamic loss coefficients under DC bias, a calculation method based on the Statistical Theory of Losses (STL) is established by investigating the law of influence of DC bias on hysteresis loss and dynamic loss. The effectiveness of the proposed method is verified.

Based on the evacuated tube high- T c superconducting (HTS) side-suspension (SS)-maglev circular track system which reached the maximum running speed of 160km/h, we studied the dynamical magnetic resistance of the maglev vehicle moving along the magnetic track. Different magnetic field gradients are formed by stacking silicon steel sheets on the surface of permanent magnet guideway (PMG) in this work. The running resistance of the prototype vehicle under different magnetic field gradients is acquired by processing the velocity attenuation data measured via acceleration sensor during the running process. The corresponding magnetic resistance is obtained by further data processing and analysis. A peak was observed in the low speed range of the speed dependent curve of the magnetic resistance, which can be attributed to the influence of the resonance. When the running speed of the maglev vehicle exceeds a certain value, the magnitude of magnetic resistance is positively related to the running speed and magnetic field gradient. The results of this study can provide a reference for the optimization of the manufacturing cost, performance, maintenance and safety in the application of HTS maglev vehicle.

The magnetic property measurementfor grain oriented (GO) silicon steel sheet under non-sinusoidal excitations (DC bias and harmonic) were conducted based on the experimental platform. Based on the Preisach model, the static hysteresis and loss properties were accurately simulated. Furthermore, an improved loss model was proposed by adjusting the statistical parameter of abnormal loss, which depends on the characteristic quantities of DC bias or harmonic excitations. The simulated dynamic hysteresis loops and iron losses under different non-sinusoidal conditions were compared with the measured ones, and thus the accuracy and generality of the improved model proposed in this paper were verified. In addition, the influences of the harmonic and DC-biasing quantities upon the total losses is investigated.

This article provides an update to a paper presented in 2006, sharing the results of a decade of core repair. The process described is for a microconversion coreplate of electrical steel laminations used in ac stators, ac rotors, and dc armatures. The treatment process restores the coreplate and avoids the laborious restack process, saving time and reducing the cost to the end user.

The main scope of the paper is to apply the Design of Experiment (DoE) method and to develop a predictive model of energy losses for non-oriented electrical steels. This approach permits us to determine a mathematical model, which is the predicted response (energy losses) as a function of input data (strip width and peak magnetic polarization) and experimental results. The presented DoE model is based on a classical central composite design of type 2n + 2n + 1 with two-levels (n = 2) and as a consequence only nine experimental points are necessary. The equation system that is associated with the model, generates a surface response equation, which permits the energy loss computation for different values of width strip and peak magnetic polarization. The DoE model was implemented, using different software packages as MathCad, Excel and OriginPro 2018, in the case of two types of electrical steels namely NO20 and M300-35A alloys that are used in small size electrical machines. In this case, the strain hardening phenomena at the cut edge becomes important, due to its negative impact on energy losses. The computed results were compared with the experimental data and errors lower than 5 % were determined.

The triple junction features of 0.5 wt.% Si electrical steel in electrically assisted forming were investigated. Specimens were electrically stretched, measured with electron backscatter diffraction (EBSD) method. The results show triple junction curvature, and the difference between the maximum and minimum dihedral angles and specific triple junctions are promoted. It is concluded that increased deviation from the equilibrium of dihedral angles can be attributed to the increased triple junction curvature induced by electric current. The increased triple junction curvature enhances the driving force for triple junction motion and reduces the retarding effect of particles on the motion of triple junctions.

Previous work has studied the magnetic resistance (Fmr) of high-temperature superconducting (HTS) maglev vehicles operating at a speed lower than 40 km/h, but the characteristics of Fmr at higher operation speeds are still unclear. Based on the high-speed rotating simulation platform, this paper studies the dynamic magnetic resistance of maglev vehicle at a speed up to 250 km/h. By stacking silicon steel sheets on a circular permanent magnet guideway (PMG) to form a periodically fluctuating external magnetic field, the characteristics of the influence of strong magnetic field fluctuations on the magnetic resistance of the maglev vehicle under high-speed movement are obtained. The transient magnetic resistance of the HTS maglev system oscillates with time. The oscillation amplitude increases approximately linearly with the operating speed and is closely related to the initial magnetization state of the HTS superconductor. Due to the asymmetry of the oscillation, there is a net average magnetic resistance, whose value increases linearly with the speed, and the rate of change is dominated by the initial magnetization state of the superconductor. The oscillating characteristics of transient magnetic resistance make the net average magnetic resistance much smaller than the magnetic levitation force. The frequency spectrum of magnetic resistance oscillation shows two characteristic frequencies of 5.3 Hz and 53 Hz, and they are independent of the driving frequency.

The problem of reducing magnetic losses (no-load losses) in the steel of the magnetic cores of electrical machines is investigated. The tasc of determining the optimal thickness of steel sheets of the magnetic circuit of an electric machine is considered. The criterion for optimality is the minimum power of magnetic losses in steel. Currently, this problem does not have an exact solution due to the fact that the exact ratio of the hysteresis and eddy current components of magnetic losses in steel is unknown. Analyzed the power of magnetic losses in modern electrical machines and devices, depending on the thickness of the sheets of electrical steel. A method is proposed for determining the optimal thickness of steel sheets of the magnetic circuit of an electric machine based on the wattmeter method. In the course of the experiment, two identical magnetic circuits were selected from steel sheets of different thicknesses, for which the losses in steel were measured at different frequencies of magnetization reversal and the optimal thickness of the sheets was calculated. The proposed formula for calculating the thickness of the sheets is valid for both isotropic and anisotropic steel. The proposed technique can be used for both transformers and electric motors and generators.

The technology of melting and secondary processing of electrical silicon steel and the changes in the content of oxide nonmetallic inclusions (NIs) in the metal at the stages of its secondary processing and casting is analyzed. Fractional gas analysis and scanning electron microscopy with electron-probe microanalysis are used to study samples of three heats taken at the stages of secondary processing and casting of electrical silicon steel. The total oxygen and nitrogen content and the amount and the main types of oxide NIs (silicates, aluminosilicates, spinels) in the samples are determined. The increase in the amount of spinel NIs in the metal samples is assumed to be related to the influence of deoxidizers, and the increase in the oxygen and nitrogen content in the samples taken in a steel degassing plant and in a tundish during heat I can indicate the influence of secondary oxidation at these processing stages. Commercial heat logs are analyzed and thermodynamic calculations are performed in order to determine the factors affecting the destruction intensity of the steel-teeming ladle lining and the increase in the content of NIs and carbon in the metal samples.

In this paper, an experimental procedure is presented in order to handle magnetic measurements under uniaxial tensile stress reaching the plastic domain. The main advantage of the proposed procedure is that it does not require an additional magnetic core to close the magnetic flux path through the studied sample. The flux flows only in the sample and no parasitic airgaps are introduced, which avoids the use of H-coil to evaluate the magnetic field, often very sensitive and not easy to calibrate. A specimen of non-oriented (NO) FeSi (1.3%) sheet (M330-35A) is characterized under uniaxial tensile stress. In order to validate the proposed procedure, a comparison with the single sheet tester procedure is carried out. The results obtained by the two procedures are in a good agreement. Moreover, to illustrate the possibilities offered by the proposed procedure, we confirm some results met in the literature. We show that positive plastic strain leads to significant degradation of magnetic behavior. An applied tensile stress on a virgin (un-strained) sample leads to a magnetic behavior degradation. Whereas, on a pre-strained sample, an applied tensile stress results in reducing the deterioration caused by the plastic strain until a stress value called optimum. Above this threshold, the magnetic behavior re-deteriorates progressively.

In this study, we explore the vector magnetic properties of the electrical steel sheet under dc-biased flux and rotating magnetic field of different frequencies. The corresponding iron loss and the rotational eddy current loss are discussed. An enhanced vector magnetic hysteresis model is proposed to describe the $B$ – $H$ behavior under these conditions. The accuracy of the proposed model is verified by the close agreement between the hysteresis loops calculated with the proposed model and those measured experimentally, as well as by the neglectable calculation error of the total iron loss.

This article proposes the core loss reduction of a surface-mounted permanent magnet motor with a segmented stator core. First, it is shown that the core loss of a motor is decreased by the segmentation of a stator core made of a nonoriented electrical steel sheet. The nonoriented electrical steel sheet used as the segmented stator core has an anisotropy, which is easy to magnetize in the rolling direction. Therefore, it is important to investigate the core loss of the segmented stator core in consideration of the rolling direction of the electrical steel sheet. The rolling direction of the steel sheet can be taken into consideration in magnetic field analysis by using the Enokizono & Soda (E&S) model, which is one of the vector magnetic property utilization techniques. Accordingly, the finite-element method, which introduced the E&S model, is used to evaluate the core loss of the motor. Second, the core loss of the segmented stator core is further reduced by applying a corner radius to each tooth root. Finally, the relation between the core loss and the rolling direction in the segmented stator core applying corner radius is investigated.

Although it is well known that the magnetic properties of electrical steel can be deeply affected by the cutting process, it is still not clear how to accurately evaluate these effects on a prototyped machine on its final shape, especially at a high frequency or a high power rating. This research provides a more practical method for accurate measurement of magnetic losses in electrical steel with consideration of material degradation effects due to the cutting process. Unlike other similar studies, these investigations are conducted not only on a few laminations but also on a complete electrical machine core. For a fair comparison between both cases, backlack bonding is used for lamination stacking since it is the most non-damaging joining technique. Two different test setups are used to measure the steel performance at a wide range of frequency and input power. Furthermore, a full axial length stator of a switched reluctance machine (SRM) is used as a case study to identify the magnetic properties of NO20 electrical steel. Additionally, by comparing the results obtained from the individual laminations and the assembled stator, the extra losses due to the cutting process and material degradation are extracted accurately.

This article presents the magnetostatic analysis of a 12/10 variable flux reluctance machine where the nonlinear magnetic characteristics of the soft-magnetic material are modeled using two different techniques: the single-valued magnetization curve and Jiles-Atherton vector hysteresis modeling. The root mean square and the peak local errors in the magnetic flux density calculated by the single-valued curve are found to be 0.23 T and 0.5 T, respectively. Moreover, the calculated torque under magnetic saturation with a single-valued curve exhibits over 5% error when compared to the Jiles-Atherton model, as it only models uni-directional material characteristics. Lastly, the modeled hysteresis loss of the applied two techniques is compared. The discrepancy between the two models is found to be 25% in magnetic saturation and reaches 48% for large dcto ac-field excitation ratios in the linear region

PurposeThis paper propose an algorithm for the multiple silicon steel coils multiperiod two-dimensional lengthwise cutting stock problem (m2DLCSP), so as to minimize the total cost of materials and production.Design/methodology/approachThe authors propose a sequential leftovers utilization correction (SLUC) algorithm for the m2DLCSP. The algorithm primarily considers three optimization strategies. First, it considers usable leftovers to simplify the cutting process and improve material utilization. The total quantity and types of leftovers should be limited in order to avoid leftover overstock. Second, it uses a splice method of items to improve the generated cutting plan. Third, it takes into account operational restrictions in the cutting operations. Operational restrictions include imposing maximum and minimum lengths on the cutting patterns, and the limitation of cutting knives at the slitting machines.FindingsSeveral sets of benchmark with real-world and randomly generated instances are provided to evaluate the algorithm. Compared with literature algorithm and current procedure applied in enterprises, the computational results indicate that proposed algorithm can effectively reduce the total cost, and the computation time is reasonable for practical use.Social implicationsThis algorithm can effectively reduce the total cost.Originality/valueThe proposed method can effectively applied to solve the m2DLCSP and improve the economic efficiency of enterprises.

The magnetic properties of cold rolled non-grain oriented (CRNO) electrical steels are determined by the optimum grain size and preferred texture, which are functions of composition, and thermomechanical processing. The annealing process plays an important role in the final magnetic and mechanical properties of CRNO electrical steels. In this work, methodology has been developed for simulating continuous annealing processes using thermomechanical simulator (Gleeble). Cold rolled full hard samples of CRNO steel with Si values 0.3, 0.7, 1.0, and 1.3% were collected and subjected to plant annealing cycles for the temperature range of 780−1000°C. Subsequently, the microstructure, texture and magnetic properties were measured in simulated samples. This paper explains the effect of Si content and final annealing temperature on the grain size and texture, and its impact on magnetic properties such as core loss and permeability. Core loss decreases with increasing annealing temperature up to a certain value and after that increase. This optimum temperature increases with increases in Si content in steel. Permeability decreases continuously with increasing annealing temperature for all Si steel because of the strengthening of magnetically unfavorable gamma fiber [〈111〉//ND (Normal direction)] texture. An empirical relationship was also developed to determine the optimum annealing temperature as a function of Si content. This off line simulation was successfully used to enhance process optimization of new grades by reducing the requirement of online trials that helps in product customization.

The use of silicon-containing steel in the manufacture of transformer cores can save raw materials and greatly reduce the volume and energy consumption of the transformer. A forsterite film of stoichiometry Mg2SiO4 formed on the steel surface provides a certain degree of insulation and forms by reaction between the oxides in internal oxidized zone and a deposited MgO coating during high-temperature annealing. In this work, the morphology evolution of internal oxidized zone and the forsterite film on the steel surface are studied when the arrangement methods for silicon steel and annealing atmosphere are different, then the relationship of morphology between internal oxidized zone and forsterite film is explored. Results showed that the morphology of forsterite film on the steel surface is closely related to the morphology of internal oxidized zone. Metallic iron particles exist in the forsterite film when an iron layer exists in the surface of internal oxidized zone.

Unstabilized nitrogen-containing silicon steel 03Kh18N13S2AM2VFBR-Sh (EP 302M-Sh), intended for heat exchanger tubes operating in contact with heavy liquid-metal coolants and water at temperatures of 350 to 550°С, is prone to prolonged thermal aging and sensitization, initiating local metal corrosion in water at 350°С. Changes in the chemical composition of steel and the production of pilot batches of heat exchanger tubes did not lead to an increase in their thermal stability. One of the reasons for this is the factor of nitrogen solubility in austenite, which was neglected during the development of chemical compositions of metal. The principles of alloying and the conceptual chemical composition of unstabilized austenitic steel (EP 302M1-Sh), not prone to thermal aging and sensitization at a temperature of 350°С, have been developed, which excludes the possibility of local corrosion of the heat exchanger tubes during long-term operation in water. A 25% increase in yield point at 350°С compared to steel 08Kh18N10T and the absence of susceptibility to pitting, crevice, and hideout corrosion make thermally stable steel the preferred candidate material for producing heat exchanger tubes for innovative water-cooled power reactors. A possibility of creating economically alloyed austenitic steel, characterized by thermal stability at 350 to 550°С and corrosion resistance in liquid-metal coolants and supercritical steam-water medium, is shown.

This article discusses the influence of ferrite inequigranularity on magnetic properties of silicon electrical steel. The influence of inequigranularity on specific magnetic losses has been quantitatively estimated at different grain size and alloying level, and the validity of this property has been confirmed. The influence of inequigranularity becomes more obvious with increase in alloying with silicon and aluminum and decreases to an insignificant level with increase in the average grain size of the ferrite phase.

A comparative study of precipitates, microstructure, texture and magnetic properties between conventional and Nb-bearing grain oriented silicon steel was carried out. The results show that fine and...

To estimate the magnetic properties with two-dimensional AC-magnetization with two-dimensional DC-biased magnetization, three different grades of non-oriented electrical steel sheets with two-dimensional DC-biased magnetization were prepared. As a result, in the high grade specimen, the difference in the magnetic properties depending on the excitation direction (AC excitation direction is parallel to DC excitation direction) was larger than in the low grade specimen, and the magnetic properties were the best when the excitation direction was the rolling direction. Non-oriented electrical steel sheets have small magnetic anisotropy. High grade non-oriented electrical steel sheets have a large magnetic anisotropy to compare with low grade non-oriented electrical steel sheets. It is thought that magnetic anisotropy increased in the high grade non-oriented electrical steel sheets because the B-H loops under DC-biased magnetization were minor loops. In addition, the increase rate of the H widths and the increase rate of the iron losses depending on the excitation direction were relatively consistent. Since the iron loss is proportional to the area of the B-H loop, it is considered that the iron loss increased at the same rate as the H width of the B-H loop.

In order to calculate the iron loss in motors with high accuracy, it is necessary to consider skin effect of the eddy current in laminated electrical steel sheets. To solve this problem, the post 1-D analysis is used. It divides every element along the thickness and calculates the distribution of the eddy current and magnetic flux density. In this article, we propose improved post 1-D analysis using the distribution of the differential permeability. In this method, 1-D equation has second differential term using differential permeability coefficient. By using the differential permeability, it is possible to express the sensitivity of the magnetization correctly.

This article presents an algorithm for identification of anomalous magnetic field and loss in silicon steel sheet (SSS). Since the magnetic field in an SSS consists of static hysteresis, eddy current, and anomalous magnetic fields, the anomalous magnetic field is extracted from the measured hysteresis field by excluding the static hysteresis and eddy current fields. In order to predict the anomalous magnetic field for an arbitrary $B$ -waveform, an artificial neural network model with deep learning algorithm is suggested. Through comparisons with experimental measurements over a non-oriented electrical steel sheet, 35PN440, the proposed algorithm is validated.

In this article, a finite element (FE) modeling of the punching effect on the magnetic properties of electrical steel sheet is carried out. For that, the modified anhysteretic Sablik model is applied together with the plastic strain distribution obtained from a punching process simulation performed using the software ABAQUS. First, a synchronous electrical machine is simulated including the effect of the punching process, and it shows the degradation of the magnetic flux density at the lamination edges and an increase of the iron losses. Then, results obtained from the magneto-mechanical simulation are investigated in terms of the method used to implement the plastic strain distribution in the FE computation. Two examples have been investigated: a square steel sheet and a tooth of an electrical machine.

In this article, an impedance debris sensor capable of simultaneously detecting inductance and resistance parameters is presented, which mainly consists of two planar coils in parallel, two excitation silicon steel strips inserted in the inner hole of coils and a built-in silicon steel strip located in the center of channel. The excitation silicon steel strips and the built-in silicon steel strip establish a detection region with a high-gradient magnetic field to improve the sensitivity of the sensor. And the square channel makes full use of the sensitive detection region, thereby further increasing the detection throughput. Experiments have shown that the amplitudes of the inductance and resistance pulses generated by the same particle many times through the detection region are different. The uncertainty of the sensor can be reduced for accurate size information by combining the detection results of the inductance and resistance parameters. By comparing and analyzing the inductance parameter detection result and the resistance parameter detection result, the impedance debris sensor can distinguish and measure 25 μ m iron particle and 85 μ m copper particle. With its high sensitivity, high throughput, and capability of multiparameter detection, this sensor can potentially be used for health monitoring of hydraulic equipment.

Temperature is one of the basic parameters in the life of the mankind and particularly in steel industry. After discovery of thermoelectric effect by T.I. Zeebeck and creation of the thermoelectric thermometer, production of steel was transformed from an art into a highly qualified labor. It was shown, that thermocouples have considerable benefits comparing with other temperature sensors: radiation pyrometers and resistance thermometers. Items of temperature measurement in steel industry considered. Methods of temperature control in technological processes of steel industry qualified. Some results of studies of industrial heating furnaces of hot-rolling mills, chamber, bell-type and continuous furnaces presented. The studies were accomplished at the Department “Thermal physics and ecology of metallurgical production”, in the center “ENERGOMET”, at the enterprise “Innovations and energy saving”, in the laboratory “Heat engineering measurements in metallurgy” of NITU “MISiS”, in OJSC “Obninsk thermoelectric company”. Examples of temperature measurement in heating and thermal furnaces of rolling mills presented. Design of a thermometer for temperature measurement in a toxic or highly explosive atmosphere presented, based on a method of pulsating convection thermometry of a gas, developed at MISiS. The device ensured accurate enough gas temperature measurement in operating furnaces and enabled to organize a correct supply of a protective gas into the heating chamber, exposure and its effective motion in the working area resulting in increasing intensity of decarburization process of transformer steel in tower furnaces.

The improvement of recrystallization texture and magnetic properties in grain-oriented electrical steel with trace Bi addition processed by strip casting process was studied in this study. Low casting temperature and sufficient liquid steel flow during strip casting process enabled relatively homogeneous distribution of Bi in the as-cast strip, which accelerated the precipitation during solidification and cooling process. As a result, relatively high density of duplex MnS + AlN, MnS and AlN was formed at grain boundaries and inside grain. Due to the synergistic effect of continuous precipitation and fragmentation of coarse precipitates during cold rolling, the number density of precipitates was increased and mean size was decreased along the processing route. High density of precipitates is attributed to severe inhomogeneous plastic deformation, which promoted the formation of high density in-grain shear bands during cold rolling and recrystallization Goss texture during annealing. Homogeneous microstructure with average grain size of ~ 11.6 μm, strong Goss texture with intensity of 2.5 multiples of random distribution, fine precipitates with number density of ~ 1.9 × 109 /cm2 and mean size of ~ 49 nm were formed after primary recrystallization annealing. Furthermore, grain-oriented electrical steel with Bi addition experienced complete secondary recrystallization of exact Goss grains during high-temperature annealing, which is attributed to beneficial optimization of Goss texture and strong inhibition effect, and superior magnetic induction B8 of 1.91 T was obtained. It is expected that this study paves a new way for fabrication of high-performance grain-oriented electrical steel.

Non-grain-oriented (NGO) cold rolled steel is widely used in magnetic cores of rotary electric machines such as electric motors and power generators due to the excellent magnetic permeability and low magnetic loss, as well as low magnetic anisotropy, which means uniform magnetic properties in all directions due to the diffuse crystallographic texture of grains. Currently, due to the expansion of the functional application field and the increasing demand for electric motors with large power and small dimensions, there is a need for further development of an economically sound technology for the production of commercial rolled products from high-performance electrical steel with a controlled crystallographic texture. Some aspects, problems, and prospects of progressive practice in the production technology and application of this steel have briefly been discussed in the paper.