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Presents information on a study which investigated the origin of magnetic easy axis in pipeline steel using an angular magnetic Barkhausen noise (MBN) technique. Application of angular MBN to monitor magnetic anisotropy; Experimental technique; Results and discussion; Conclusions.

Highlights • The high magnetic field increases the number density of carbides by twice. • Denser carbides increase the dislocation density by larger critical unpinning stress. • Hardness remains unchanged because the increase in offset the reduction in hardness. Abstract The influence of a 12 Tesla magnetic field on the microstructure of high Chromium-containing steel during tempering was investigated. The experimental results revealed that an external magnetic field significantly increases the number density of carbide (Fe, Cr) 3 C and the dislocation density. The external magnetic field decreases the Gibbs free energy of (Fe, Cr) 3 C and then decreases the nucleation barrier; hence, the number density of (Fe, Cr) 3 C increases by approximately 2.42 times. The higher number density of carbides doubles the dislocation density, corresponding to the larger critical unpinning stress τ c , which results in a dislocation pile-up in front of the carbides. The hardness change is negligible with an external 12 T magnetic field because the increment of hardness due to the denser carbides (Fe, Cr) 3 C and dislocations that originate from the 12 T magnetic field offsets the decrement of hardness that results from the decrease in the solid solution strengthening from the carbon atoms. The investigation of the impact of an external high magnetic field on the behavior of carbides and dislocations can provide a better understanding for the precipitation strengthening mechanism of nuclear fusion steels. [ABSTRACT FROM AUTHOR]

In this paper, the magnetic properties of non-oriented (NO) and grain-oriented (GO) silicon steels with dc-biased induction are measured and analyzed within the wide range of 20–1000 Hz, 0–1.9 T. While by the physical method, we found that all the ac-, dc-, and dc-biased fields do not influence the electrical resistivity of silicon steel, and hysteresis loss is mainly responsible for the iron loss increase when dc-biased induction exists. With the frequency and ac induction going up, the effect of dc-biased induction on iron loss will become weak. Compared with NO steel, iron loss of GO steel is more sensitive to dc-biased induction. The validation shows that existing iron loss models which claim to consider dc-biased magnetic induction are not satisfactory up to now when applied in the wide range of dc-biased induction, ac induction, and frequency. [ABSTRACT FROM AUTHOR]

Highlights • Low field magnetic permeability up to Curie point reported for ferrite-pearlite steels. • FE microstructure model to predict permeability-temperature relationship developed. • Excellent agreement between modelled and measured data for ferrite-pearlite steels. • Model can predict permeability-temperature data for ferrite-austenite microstructures. Abstract The magnetic properties of steels are sensitive to temperature and currently the only way to determine them is by experimental measurement. In this work a cylindrical shaped ceramic cored EM sensor has been used to measure the low magnetic field inductance of pure iron and C-Mn steels with ferrite + pearlite microstructures during heat treatment up to 800 °C in a furnace. The low field relative permeability values have been determined by fitting the sensor readings to a finite element sensor model generated in COMSOL, where the model has been validated for room temperature measurements using samples of known low field relative permeability. The low field relative permeability values with temperature follow the expected trend of increasing values with temperature, particularly close to the Curie temperature. The measured low field relative permeability values for the mixed ferrite + pearlite microstructures have been compared to predicted values from an FE microstructure-permeability model using the single phase (ferrite or pearlite) low field relative permeability values as input. The model predictions agree well with the experimentally measured values allowing any two-phase ferrite + pearlite microstructure low field relative permeability with temperature relationship to be determined. The model has also been used to determine the low field relative permeability of ferrite + austenite microstructures with temperature. [ABSTRACT FROM AUTHOR]

Highlights • The magnetic properties of electrical steel sheet are measured by two specimens. • The effect of temperature and pressure on magnetic properties is revealed. • The difference in results is related to environmental factors, shape and size. Abstract Motor made of electrical steel sheet is sometimes used in extreme environments, for example, submersible motors are operated at temperatures and pressures coupling environment. However, most related reports only consider the effect of single environmental factor (temperature or stress) on the magnetic properties of electrical steel sheets. Therefore, in order to accurately design a motor that can operate at temperatures and pressures coupling environment, the magnetic properties of electrical steel sheets used in the motor should be clarified firstly. In the paper, two kinds of specimens (ring specimen and rolled specimen) are used to measure the magnetic properties under temperature and pressure coupling environment. It not only reveals the influence of temperature and pressure coupling environment on the magnetic properties, but also analyzes the difference between the measurement results obtained by two kinds of measurement samples. The measurement results show that the effect of pressure on magnetic properties decreases with increasing temperature under the conditions of temperature and pressure coupling. According to the domain theory, a reasonable explanation for the influence of temperature and pressure coupling environment on electrical steel sheet is given. Meanwhile, combining the shape and size of the two measurement samples, the possible causes of the differences in the measurement results of the two measurement samples were analyzed in detail. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Coercivity of the α′-martensite is characterized by strong magnetic shape anisotropy. • α′ → γ transformation is split into two stages during continuous annealing. • Magnetic properties present an annealing time-dependence between 500 and 600 °C. • Formation of γ-nanograins in the early stages of reversion induces strong magnetic shape anisotropy. • Athermal α′-formation within the prior athermal ε-phase is observed for temperatures lower than 100 °C. Abstract Strain-induced martensite (SIM) formation was evaluated upon cold-rolling of a 17.6 wt.%Mn-TRIP steel by means of magnetic measurements, X-ray diffraction, and high-resolution electron backscatter diffraction (EBSD). α′-martensite formation was observed to be dependent on the presence of prior ε-martensite. Upon deformation, the coercivity of the ferromagnetic α′-martensite is characterized by strong magnetic shape anisotropy. Austenite (γ) reversion was evaluated by means of in situ magnetic measurements during continuous annealing. The experimental results were compared to thermodynamic simulations. It turned out that γ-reversion was not completed in the regime where a γ-single phase field is expected, which suggests the splitting of α′ → γ transformation into two stages. The Curie temperature of remaining α′-martensite was determined as being ∼620 °C. Magnetic properties presented an annealing time-dependence within the temperature range of 500–600 °C, suggesting long-range diffusional α′ → γ transformation. With the aid of electron channeling contrast image technique (ECCI), we noticed that the formation of γ-nanograins in the early stages of reversion is sufficient to induce strong magnetic shape anisotropy in this steel. After full austenitization at 800 °C, further in situ magnetic measurements were also used to track the magnetic response of the material upon controlled cooling. Athermal formation of α′-martensite within the prior athermal ε-phase was clearly observed for temperatures lower than 100 °C. Using thermodynamic modeling we also calculated the start temperature for ε-formation (M s ε). Results showed that ε-martensite is indeed expected to form before α′, which was confirmed in all cases by means of EBSD. [ABSTRACT FROM AUTHOR]

In this paper, we investigate modeling methods of magnetic properties considering the hysteretic properties and the excess eddy-current loss. First, a simple method in which an excess magnetic field given by the Bertotti's model is added to a surface magnetic field as a post-processing of the 1-D finite-element analysis is compared with a 1-D finite-element method directly considering an excess magnetic field. Additionally, homogenization methods of magnetic property of an electrical steel sheet with the Bertotti's model are discussed from the standpoints of computational accuracy and costs. [ABSTRACT FROM AUTHOR]

The submerged entry nozzle (SEN) clogging has been happening during continuous casting (or CC for short) for nonoriented silicon steel. To solve the problem, the paper studied a flow rate through SEN, a node attached to one of them, and the impact on the clogging. The results showed that when SEN is clogged seriously, the casting speed has to decrease below the target casting speed and that SEN clogging can be predicted by comparing the actual value and the theoretical one of a casting speed. Al2O3 and its composite inclusions caused the SEN clogging and the addition of Ca can solve SEN clogging during CC of the silicon steel both theoretically and practically. Furthermore, the impact of the addition of Ca on the magnetic properties of the steel were analyzed. The results showed that the core loss and the magnetic induction of the silicon steel decreased by using the addition of Ca, which generated more dissolved Aluminum, and the addition of Ca generated more harmful textures, which reduced the magnetic induction. [ABSTRACT FROM AUTHOR]

It has been shown theoretically and experimentally that locally magnetizing rebar through a protective layer of concrete makes it possible to determine both the depth of the protective layer of concrete and the diameter of rebar based on stray magnetic fields regardless of the magnetic properties of steel that rebar is made of. [ABSTRACT FROM AUTHOR]

Specimens of austenitic stainless steel were compressively deformed or irradiated with Xe ions at room temperature. The characterization of the magnetic properties and microstructural variations were done by vibrating sample magnetometer, grazing incidence X-ray diffraction and TEM. The results indicated that higher deformation or irradiation damage causes more significant magnetization phenomenon. The amount of ferromagnetic phase can be deduced from M s and increases with deformation and irradiation. The stress relief after deformation or irradiation may be responsible for the ferromagnetic phase formation. H c increases first and then decreases continuously with a turning point at deformed to 40% or irradiated to 2dpa. The different contributions of dislocation density and ferromagnetic precipitates on H c can explain this variation. [ABSTRACT FROM AUTHOR]

Presents a study which investigated the stress-dependent magnetic easy axis in steel with the use of magnetic Barkhausen noise. Analysis of stress effects on single iron crystals; Experimental technique; Results and discussion.

This study has been done by separately measuring Magnetic Barkhausen noise (MBN) under different structure characteristics, namely the carbon content, hardness, roughness, and elastic modulus in commercial steels. The result of the experiments shows a strong dependence of MBN parameters (peak height, Root mean square (RMS), and average value) on structure characteristics. These effects, according to this study, can be explained by two kinds of source mechanisms of the MBN, domain wall nucleation and wall propagation. The discovery obtained in this paper can provide basic knowledge to understand the existing surface condition problem of Magnetic Barkhausen noise as a non-destructive evaluation technique and bring MBN into wider application. [ABSTRACT FROM AUTHOR]

Strip-cast grain-oriented 4.5% Si steel was produced by short-term isochronal secondary annealing (15 min) and isothermal annealing (1000 °C) under hydrogen atmosphere. The relationship between the evolution of grain structure and magnetic properties was elucidated. It was observed that during isochronal annealing, abnormal grain growth occurred followed by normal grain growth with the increase of annealing temperature. Additionally, decreasing the primary annealing temperature accelerated the isochronal annealing kinetics, and near complete abnormal grain growth with optimal magnetic properties was obtained at lower temperature. Furthermore, during isothermal annealing, abnormal grain growth successfully occurred and magnetic properties were continuously improved with the increase of annealing time. The optimal magnetic properties were superior to those of isochronal annealing because of sharper secondary Goss texture and reduced retention of second-phase particles. The grain-oriented 4.5%Si steel in the present study indicated superior properties and better workability than the previously reported non-oriented 6.5%Si steel. Thus, grain-oriented 4.5%Si steel produced by short-term secondary annealing can potentially replace non-oriented 6.5%Si steel. [ABSTRACT FROM AUTHOR]

With excellent mechanical properties because of strain-induced martensitic transformation (SIMT), applications of austenitic stainless steels can be extended to a further broad range of engineering fields. In order to discover applications from a clarification of their mechanical properties, especially at higher deformation rate, it is important to evaluate an amount of martensite, which can control such excellent performances of the steels during deformation. However, until now, it is quite hard to find experimental studies for the evaluation during deformation at various strain rates. In the past, volume resistivity and impedance have been measured during deformation. However, these studies have not been successful to evaluate it with a higher precision. Instead of those, it is useful to measure directly relative magnetic permeability, which has a correlation with the amount of martensite, because of focusing on a ferromagnetic characteristic of martensite. In this study, at first, SUS304, which is a kind of austenitic stainless steels, is deformed plastically under tension at various strain rates. Then, it is attempted to evaluate the amount of martensite during deformation by measuring the relative magnetic permeability expressing ferromagnetism directly. Finally, the strain and strain rate sensitivity of SIMT in the steel is discussed by obtained results. [ABSTRACT FROM AUTHOR]

Laminations of non-grain-oriented (NO) electrical steel grades for magnetic cores of electrical machines should feature homogenous magnetic properties within the entire sheet plane. Basic empirical models have been introduced to estimate and correlate magnetic properties with microstructural material parameters. In these considerations, the steel sheets are generally considered to be homogenous, i.e., orientation dependence and variations across the sheet thickness are often disregarded. Whether or not, these simplifications are justified and how grain size and texture are described most suitable for correlations with magnetic properties is the focus of this paper discussing four industrial NO steel grades. [ABSTRACT FROM AUTHOR]

Stainless steel containers are widely used in the pharmaceutical and biopharmaceutical industry for the storage of buffers, process intermediates, and purified drug substance. They are generally held to be corrosion resistant, biocompatible, and nonreactive, although it is well established that trace amounts of metal ions can leach from stainless steel equipment into biopharmaceutical products. We report here that the use of stainless steel containers in conjunction with magnetic stirring bars leads to significantly aggravated metal contamination, consisting of both metal particles and significantly elevated metal ions in solution, the degree of which is several orders of magnitude higher than described for static conditions. Metal particles are analyzed by scanning electron microscopy with electron-dispersive X-ray spectroscopy, and metal content in solution is quantitated at different time points by inductively coupled plasma-mass spectrometry. The concentration of iron, chromium, nickel, and manganese increases with increasing stirring time and speed. We describe the impact of buffer components on the extent of metal particles and ions in solution and illustrate the effect on model proteins. [ABSTRACT FROM AUTHOR]

In this paper, a novel three-dimensional (3-D) magnetic tester with symmetrical orthogonal excitation structure and cubic field-metric sensing structure is designed and analyzed. Automatic measurement system, which includes feedback control method, harmonics compensation, and automatic data processing is developed for the 3-D magnetic tester. In order to improve the measurement precision, cross effects of the magnetic fields in three principal directions are concerned, and error mitigation methods which fit for different excitation models are proposed. Magnetic properties of typical grain-oriented (GO) and nongrain- oriented (NGO) laminated silicon steel specimens under alternating and rotating excitations are measured and analyzed by using the designed 3-D magnetic tester. [ABSTRACT FROM AUTHOR]

Although two-dimensional (2-D) magnetic properties can be measured by using a 2-D single sheet tester (SST), the construction of the reliable 2-D SST is considerably difficult. By contrast, the flux density and magnetic field parallel to the excitation direction can be measured in a normal one-dimensional (1-D) SST. If the average flux density points toward the excitation direction in a specimen with any inclination angle from its rolling direction, the magnetic energy can be defined and therefore 2-D magnetic properties can be calculated by means of an energy-based modelling method. However, the direction of the flux density and magnetic field in the 1-D SST has not been deeply discussed when a specimen with any inclination angle is measured. In this paper, the behavior of the flux density and the magnetic field strength is examined by using 1-D SST. The direction of the flux density is measured by using a pair of cross B-coils. The direction of the magnetic field strength is measured by using a pair of cross H-coils. The effect of the specimen width on the distribution of flux density is also investigated by using a magnetic field analysis. As a result, when a pair of cross H-coils is adopted to a specimen with appropriate aspect ratio, 2-D magnetic properties can be measured by means of the 1-D SST. [ABSTRACT FROM AUTHOR]

This work investigates the microstructure and texture evolution in grain-oriented electrotechnical steel with a new inhibition system based on vanadium carbides nano-particles. The novel approach for the preparation of this steel with appropriate final magnetic properties combines not only nanoinhibitors based on the vanadium carbides precipitations but also includes strain-induced grain growth mechanism in combination with dynamic continuous annealing during the secondary recrystallization. The experimental grain-oriented steel with proposed new chemical composition was prepared in laboratory conditions. The texture analysis has shown that suggested procedure led the formation of sufficiently strong {110}<001> Goss texture during the short time period of a final annealing process, which is comparable to that obtained in the conventionally treated grain-oriented steels. [ABSTRACT FROM AUTHOR]

The magnetic properties of fine-grained doubly oriented Si steel sheets of 0.25-0.35 mm in thickness have been investigated. The doubly oriented Si steel sheets with grains of about 0.5 mm in diameter showed a large induction B[SUB8] of about 1.9 T as well as a 35% smaller core loss than the previously studied coarse-grained doubly oriented materials. This decrease in core loss associated with the grain size reduction is primarily due to a large decrease in eddy current loss. The core loss was further decreased by applying tensile stresses and by a reduction in sheet thickness. A tensile-stressed 0.25-mm-thick material showed a small core loss of 0.82 W/kg at 1.7 T and 50 Hz. The material also showed relatively small core losses under alternating fields below 500 Hz. [ABSTRACT FROM AUTHOR]

Magnetic hysteresis loops in three orthogonal directions are measured for a line pipe steel sample while the external magnetic field is applied in a direction perpendicular to the tensile stress direction. The total magnetization vector is calculated. This tends to the stress direction when tensile stress is applied. The reversible and irreversible differential magnetic susceptibilities are derived. It is found that the susceptibilities in all three directions are enhanced with increasing tensile stress, although the increase in the stress direction is much larger than in the other directions. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Microstructural attributes of steels affect hysteretic magnetic properties because the microstructure affects domain wall movement and pinning. Two important features are grain size and dislocation density. The consensus experimentally is that the coercivity tends to be linearly related to the inverse of the average grain diameter and to the square root of the dislocation density. In this article, these experimental tendencies are utilized in formulating the dependence of the hysteresis parameters of the Jiles-Atherton model as a function of grain size and dislocation density. The results are then used in computing the first and third harmonics of the magnetic induction as a function of grain size and dislocation density. This is done via an adaptation of a hysteresis model formulated by Jiles for higher excitation frequencies. The results indicate that the harmonic amplitudes decrease monotonically with inverse grain size and the square root of dislocation density. Sin! ce increasing inverse grain size and dislocation density are correlated with increasing tensile strength, the results are consistent with experimental results for the decrease of the harmonic amplitudes with increasing tensile strength in automotive steels. Also, the harmonic amplitudes decrease with increasing excitation frequency, consistent with experiment. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Examines the effects of laser scribing on the core losses of soft magnetic materials. Experimental methods; Results and discussion; Conclusions.

The magnetic characteristic of magnetic steel sheets used for rotating machines can be degraded by punching, cutting, or other manufacturing process. This degradation damages the performances of motors. This paper presents topology optimization of rotating machines considering the localized magnetic degradation caused by punching process. It is shown that the optimized synchronous reluctance motors obtained by this method satisfy the torque constraint under the existence of the magnetic degradation. [ABSTRACT FROM AUTHOR]

Eddy current losses are evaluated on FEM (finite element method) models of magnetic steel rings. DC magnetization curve has been obtained from measurements on steel samples and is used in FEM models for defining relative magnetic permeability of magnetic steel. Calculation is made with time 'step-by-step' (transient) and quasi-static (time-harmonic) nonlinear solvers. Results of nonlinear calculations are compared to measurements made on two magnetic steel rings. Difference in losses when applying forced sinusoidal current or voltage source is analyzed. Using transient calculation, waveforms of total flux and magnetic field on the surface of magnetic steel are shown. Waveforms show clear presence of higher harmonics. Further on, nonlinear time-harmonic method is used for calculation of losses on a 3D special stray flux experimental model. Model consists of winding, core and magnetic steel plate. Loss measurement and FEM computation are compared for different values of excitation currents and clearances between plate and core. [ABSTRACT FROM AUTHOR]

In the paper, a benchmark in the area of induction heating is presented in order to test methods and codes of field analysis in a comparative way. In particular, the transient thermal analysis of a magnetic steel cylindrical billet is considered: the coupled-field problem is characterized by a twofold non linearity, i.e. the dependence of magnetic permeability on both field strength and temperature. [ABSTRACT FROM AUTHOR]

The primary goal of this research is to investigate the effect of loading speed on the stress-induced magnetic behavior of a ferromagnetic steel. Uniaxial tension tests on Q235 steel were carried out with various stress levels under different loading speeds. The variation of the magnetic signals surrounding the tested specimen was detected by a fluxgate magnetometer. The results indicated that the magnetic signal variations depended not only on the tensile load level but on the loading speed during the test. The magnetic field amplitude seemed to decrease gradually with the increase in loading speed at the same tensile load level. Furthermore, the evolution of the magnetic reversals is also related to the loading speed. Accordingly, the loading speed should be considered as one of the influencing variables in the Jies-Atherton model theory of the magnetomechanical effect. [ABSTRACT FROM AUTHOR]

The purpose of this work was to study the influence of different kinds of rolling on the magnetic properties of NOG steel, an electric steel widely used in electrical motors. These properties are highly correlated with the crystallographic texture of the material, which can be changed by rolling. Three kinds of rolling were examined: conventional rolling, cross-rolling and asymmetrical rolling. The crystallographic texture was determined by X-ray diffraction and the magnetic properties were calculated from a theoretical model that related the magnetic induction to crystallographic texture through the anisotropy energy. The results show that cross-rolling yields higher values of magnetic induction than the other processes. [ABSTRACT FROM AUTHOR]

An ultra-low carbon grain-oriented silicon steel as-cast strip is produced by twin-roll strip casting process, and subsequently subjected to one-pass hot rolling, one-stage cold rolling, primary annealing, and secondary annealing. The effect of hot rolling process on microstructure, texture, and inhibitor evolution is studied. It is shown that the precipitation behavior of AlN particles is significantly affected by the hot rolling temperature and the optimal precipitation temperature is ≈1100 °C. On the other hand, the intensity of Goss texture in hot-rolled sheets is determined by hot rolling reduction, which is limited in the strip casting process and the hot-rolled Goss texture is relatively weak compared to the conventional process. The primary annealed Goss texture can originate from the cold rolling process and this texture is homogeneous through the thickness, besides the inherited hot-rolled Goss texture mainly presented in the subsurface layer. Thus, relatively strong Goss texture in primary annealed sheets is obtained. The results indicate that the hot rolling process is an efficient way to optimize the texture and precipitation in strip-cast silicon steel, and relatively good magnetic properties can be obtained by the strip casting process. [ABSTRACT FROM AUTHOR]

The mechanical properties of dual Phase steels (DP steels) are strictly related to the spatial distribution and the geometry of the two phases composing the steel, ferrite and martensite. Due to the high costs to obtain images of sections of steel samples, one important industrial problem is the reduction of the number of 2D sections needed to build and simulate a geometric model which may reproduce in a realistic way the 3D geometry of the material. In this context, the availability of suitable techniques of parameter estimation or identification is fundamental to solve the problem. In this work we present a germ-grain model which approximates the main geometric characteristics of the martensite, taking into account the inhomogeneities of the material. The parameters of the model are estimated on the basis of the morphological characteristics of the images of about 150 tomographic sections of a real sample, quantified by the Minkowski functionals. Here we replace the Mahalanobis distance, introduced in previous literature, with the $\mathcal{N}$ -distance, which provides computational advantages. In order to test if the estimated model is reproducing the distribution of the Minkowski functionals of the real material, both confidence bands from the simulated model are computed and compared with the real data and techniques for the detection of functional outliers are applied to quantify the accuracy of fit of the estimated model. [ABSTRACT FROM AUTHOR]

Focuses on a study which analyzed the magnetic properties of grain oriented silicon steel prepared by secondary recrystallization technique. Preparation of the study sample; Grain structure of secondary recrystallized silicon steel; Description of the direct current hysteresis curves of grain oriented silicon steel.

Details a study which investigated the magnetic behavior of grain-oriented steel sheet under various elliptical field conditions. Description of the measuring equipment; Analysis of eddy current and saturation effects of the core measurements; Results and discussion.

A method for the monitoring of residual stress distribution in steels has been developed based on non-destructive magnetic permeability measurements. The dependence of differential permeability on residual stresses induced through a controlled process of applied tensile and compressive stress in the elastic region, of all three zones of the welded metal, yields the magnetic stress calibration curve (MASC). MASC is obtained on flawless welded steel plates and can be measured for any grade of ferromagnetic steels. A surface MASC correlates the magnetic permeability with the spatial stress distribution, as determined by the X-Ray Diffraction Bragg-Brentano diffraction. A bulk MASC correlates the bulk magnetic permeability with residual stresses, as determined by the neutron diffraction. The resulting calibration curves, obtained for several grades of ferromagnetic steels, have a sigmoid shape but are unique for each grade of steels. Normalizing the magnetic permeability and the stress values against the differential permeability measured at the yield point and yield stress, respectively, the dependence of the local magnetic permeability on residual stresses for all different tested grades of steels results in a universal curve relating magnetic and elastic properties of steels at the macroscopic level. [ABSTRACT FROM AUTHOR]

Nowadays, optimization of non-oriented (NO) electrical steels toward lower iron-loss, improved, and isotropic magnetizability is critical to the improvement of rotating electrical machines. The whole production process chain adjusts the microstructure evolution, e.g., grain size and crystallographic texture, determining the magnetic properties. In particular, the interdependence of raw material properties and the resulting mechanical stress distribution during final assembly, e.g., punching, leading to magnetic property deterioration is crucial for the optimization of NO steel properties of rotating machines. This paper studies the effect of different cold rolling strategies, annealing treatments, and sheet metal blanking (punching) regarding microstructure evolution, magnetic properties, and deterioration. [ABSTRACT FROM AUTHOR]

In this paper, a new portable magnetic perturbation probe using a Giant Magneto-Resistance (GMR) sensor to detect and characterize surface cracks in ferromagnetic steels is presented. Measurements from one tangential component of the magnetic flux density are obtained during a single scan over a crack, and two parameters are defined from the output voltage of the GMR sensor: the distance between the peaks, DX, and their voltage difference, DV. The correlations between DX and DV and crack features such as depth, width, and orientation angle are determined. Sensitivity analyses are performed based on the studied features. The probe permits the user to obtain the crack׳s orientation angle using only one measured tangential component of the magnetic flux density. A simple procedure to estimate the crack׳s features is proposed based on the presented analysis. [ABSTRACT FROM AUTHOR]

Six types of stainless steels (SS) were studied for changes in its structure and magnetic properties under mechanical treatment. Depending on intensity and duration of the process of plastic deformation and the SS type the paramagnetic austenite structure transforms partially to completely into ferrite structure with ferromagnetic behaviour. Some of the SS tested were found slightly modified yet in the process of its manufacturing. Only one SS type with high Ni content preserved its structure and paramagnetic properties even after very intense mechanical treatment. [ABSTRACT FROM AUTHOR]

The performance and degree of efficiency of industrial transformers are directly influenced by the magnetic properties of high-permeability steel laminations (HPSLs). Industrial transformer cores are built of stacks of single HPSLs. While the insulating coating on each HPSL reduces eddy-current losses in the transformer core, the coating also induces favorable inter-granular tensile stresses that significantly influence the underlying magnetic domain structure. Here, we show that the neutron dark-field image can be used to analyze the influence of the coating on the volume and supplementary surfacemagnetic domain structures. To visualize the stress effect of the coating on the bulk domain formation, we used an uncoated HPSL and stepwise increased the applied external tensile stress up to 20 MPa. We imaged the domain configuration of the intermediate stress states and were able to reproduce the original domain structure of the coated state. Furthermore, we were able to visualize how the applied stresses lead to a refinement of the volume domain structure and the suppression and reoccurrence of supplementary domains. [ABSTRACT FROM AUTHOR]

The effect of polyethylene glycol [H(OCH2CH2)nOH] as quenchant was studied with a view to accessing the mechanical properties and microstructural evaluation of steel. The test samples were subjected to a conventional quenching treatment process using prepared polymer solution with a definite proportion as quenching medium. The samples were characterized using a microhardness tester, universal tensile tester for the mechanical properties and a metallurgical microscope used in analyzing its structural re-orientation. From the result, it was observed that the hardness increment of the quenched samples conform to literature review as there was also a rise in the tensile properties. This though, was at the expense of their ductility. The micrographs were found to have justified the reason for the increment recorded in some of the mechanical properties, as it displayed a high proportion of the martensitic phase. [ABSTRACT FROM AUTHOR]

A methodology to evaluate the anisotropy of magnetic properties of grain-oriented steel sheets is presented. The approach is based on the orientation distribution function (ODF) theory. The existence of sheet symmetry and orthorhombic symmetry of body-centered cubic iron crystal is discussed with ODF. As a result, in order to characterize the magnetic properties, it is sufficient to carry out measurements for three directions, since the evaluated property is directly related to the magnetocrystalline anisotropy. The presented approach may be a useful tool for the designers of magnetic circuits in electrical machines. [ABSTRACT FROM PUBLISHER]

The effects of magnetic steel shapes on air-gap magnetic flux density in Halbach magnet array of magnetically levitated planar actuators were investigated. After rectangular magnetic steel was replaced by trapezoidal magnetic steel, we deduced the magnetic flux density in Halbach rectangular magnet array using Fourier series and magnetic scalar potential. The analytical expressions of magnetic flux density in trapezoidal magnet array were obtained using the principle of superposition and the infinitesimal analysis of magnetic steel. The higher harmonic error (root-mean-square) and the relation of each harmonic peak to the ratio of length-to-polar distance at y-direction magnetised steel were investigated in Halbach trapezoidal magnet array. After the structural parameters were optimised, we analysed the effects of rolling angle of trapezoid on the y-direction magnetic field intensity, and found out the optimal rolling angle. The structural analysis shows that the trapezoidal magnetic steel can change the air-gap magnetic flux density in a very large space. [ABSTRACT FROM AUTHOR]

This paper develops an approach to evaluate and predict the effect of punching processes upon the performance of switched reluctance motors (SRMs). Punching is a common process for manufacturing of electric motors although the magnetic performance of the electrical steels at the cut edges may degrade. This could then result in a lower motor performance than expected. Annealing can usually restore the material property but it would be costly for production of common electric motors. Therefore, it is useful to compensate this effect in the design of electric motors. In this paper, the damaged range due to punching is modeled and included in the finite-element simulation for the SRMs such that the effect of this damage can be evaluated. The material properties at the cut edges are determined using the techniques developed here. Two SRMs are investigated: one being annealed after punching and the other not before assembly. Test results show that the annealed SRM produces a better performance. The comparison between the simulations and experiments shows that the developed method can be used for analysis of punching effect on motor performance. [ABSTRACT FROM AUTHOR]

The precipitation behavior of M 23 C 6 carbides and its influence on the tensile properties were investigated in a novel 0.3C–20Cr–11Mn–1Mo–0.35N austenitic stainless steel isothermally aged at 900 °C. It was found that typical M 23 C 6 carbides retaining a cube-on-cube crystallographic relation with austenite matrix precipitated on grain boundaries, twin boundaries and dislocations. With increasing aging time, the intergranular M 23 C 6 carbides grew along the grain boundaries and into the adjacent austenite grain to form a film-shaped morphology. The precipitation of cellular M 23 C 6 carbides on grain boundaries was a discontinuous reaction involving both the diffusion of C and Cr. And the formation of lamellar M 23 C 6 carbides on incoherent twin boundaries associated with the gliding of partial dislocations and the formation of stacking faults. Meanwhile, the intragranular M 23 C 6 carbides in rectangular or rhombic shapes initially nucleated on dislocations, and finally arranged in stringers corner-to-corner or face-to-face. The strength of the material was modestly improved by the precipitation of M 23 C 6 carbides, although the strengthening effect was weakened by the dominant precipitation of cellular M 23 C 6 after long-term aging duration. However, the ductility was significantly deteriorated by the intergranular and cellular M 23 C 6 . [ABSTRACT FROM AUTHOR]

There has been increased interest in using graphene oxide (GO) in various industrial applications such as working fluids, lubricants, oil and gas fields, heavy metal removal from water, anticorrosion paints and coatings etc. We studied electrochemical properties of steel in the presence of suspended GO in saline media. GO suspension has been characterized using Transmission electron microscopy (TEM) and X-ray diffractometer (XRD). We measured the effect of the GO concentration (0–15 ppm) on electrochemical properties of steel using different techniques: open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) and potentiodynamic (PD) methods. Results indicate that the suppression of corrosion is directly proportional to increasing GO concentrations in saline environments. Surface morphology of corroded samples was examined using Scanning Electron Microscopy (SEM). Identification of the elements at accumulated layer was estimated from peaks of energy dispersive x-ray spectroscopy (EDX) and XRD. Increased protection abilities with increasing GO concentration have been attributed to the domination of salt layer presence at the surface of steel which occurs via precipitation of sodium chloride. Surface analysis confirm that there is no direct effect of GO on the protection behavior of steel. The presence of GO in the solution can enhance the precipitation of NaCl due to the decreased solubility NaCl which further slows down the corrosion. The pourbaix diagram shows that GO forms an anionic compound with sodium which may enhance the precipitation at working electrode. [ABSTRACT FROM AUTHOR]