Silicon Iron Sheets Research Articles

Two-dimensional stress—magnetization effects of grain-oriented silicon steel sheets

Changes in the magnetization vector due to tensile stress under a constant magnetic field for grain-oriented silicon-iron sheet strip samples cut at various angles from the rolling direction have been investigated. In a low magnetic field, where the magnetization is less than 1.5 T, the magnetization vector lies in the direction of the sample length and the magnetization decreases with the application of tension. Beyond that magnetic field, the magnetization vector showed a two-dimensional hysteresis loop due to the application of tension. The maximum transverse magnetization change appeared in a 10° sample, where the rotation angle of the magnetization vector was 2.5°.

On the metallurgical control of texture sharpness and related magnetic properties in grain-oriented silicon-iron

The final Goss texture sharpness and the related magnetic behaviour of a grain-oriented silicon-iron sheet is, in the end, controlled by its primary recrystallization texture at final thickness. In spite of the general idea that attributes the final Goss texture sharpness control to the precision of the Goss nuclei present at that stage, it is becoming clear that the main metallurgical role is played instead by the Goss nuclei surrounding texture. This texture selects the secondary recrystallization (SR) grains in a specific Goss-oriented spread range by a mechanism comparable, in principle, to the ‘lock-and-key’ enzymatic selective catalysis mechanism, well known in biochemistry. The microstructure and magnetic behaviour differences between conventional grain-oriented (CGO) and super-oriented (HiB) sheets, as well as between various final sheet thickness products, are explained in this framework.

A simple method for the estimation of power losses in silicon iron sheets under alternating pulse voltage excitation

The prediction of iron losses in magnetic steels submitted to alternating pulse voltages is studied and an efficient method is proposed. It is developed by coupling the pulse voltage form factor and the loss separation model. Prediction of iron losses becomes possible directly from the loss model corresponding to the sinusoidal flux density. This method is validated on silicon iron grain-oriented and non-oriented magnetic steels. The predetermined iron losses are coherent with those measured and this approach allows both simplicity and precision well appreciated by industry.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Magnetic and loss characteristics of nonoriented silicon-iron under unconventional conditions

The variation of magnetic and loss characteristics of nonoriented silicon-iron sheets with frequency and temperature under sinusoidal magnetic flux-density conditions have been investigated using an Epstein frame. The investigations have made it possible to model the variation of iron loss with frequency and magnetic flux density. The practical consequences of using these models in some electrical machines are discussed.

Studies of domain wall motion. III. The field dependence of differential susceptibility at the early stage of magnetization

For pt.II see ibid., vol.3, p.4783 (1991). Differential susceptibilities chi diff of nickel wire, Permalloy-42 wire, 4% silicon iron sheet and bars of SAE 1015 and 1045 steels were measured when undergoing uniform magnetic field sweeping. The field dependences of chi diff of wires, sheet and bars at the early stage of magnetization were studied: in general, chi diff decreases with increasing sweep rate of field and the chi diff-H relationship depends on sample shape. The experimental results are interpreted using a phenomenological model based on domain wall (DW) motion that it is modest generalization of the Rayleigh law at low field. This model is also compared with a previous model of magnetomechanical damping.

Vibration Reduction of Power Transformer Core.

Recently, demand has increased for low-noise power transformers as well as large-capacity and small-size power transformers. To reduce transformer noise, it is necessary to reduce vibration of their iron cores, which is caused by magnetostrictive forces of silicon iron sheets. In this paper, a method for calculating core vibration was introduced and techniques for reducing the vibration were investigated. First, magnitudes and phases of higher-harmonic components of the magnetostriction were clarified. Then, a calculation method of core vibration using analytical solutions for a uniform beam was introduced. Calculated values for natural frequencies agreed with measured ones within 5%. Also, the vibration characteristics of a single-phase two-legged core, a three-phase three-legged core, and a three-phase five-legged core were clarified. Finally, it was found that the participation factors of magnetostriction in various portions of the core had different values for the displacement of core, and that arbitrary vibration modes could be eliminated by adjusting the magnetostriction values. Optimum combinations of magnetostriction which reduce core vibration were obtained. The preferable ratios for dimensions such as the ratio of the sectional areas of the core and yoke, or the ratio of the area moments of the inertia of the core and yoke, were proposed. In many cases, it was found that participation factors of magnetostriction in yokes were larger than those of legs, although the yokes were shorter than the legs.

一方向性けい素鋼板の圧縮応力下における磁区構造変化

The effects of compressive stress on the magnetization in grain-oriented silicon iron sheets have been investigated. The magnetization changes due to compression are composed of two effects, reversible and irreversible magnetization changes. The magnetization changes due to compression for a sample cut at a declining angle of 35° from the rolling direction have peculiar characteristics. This sample shows two peaks of magnetization change due to compression. Changes in the domain structure due to compression were observed in order to determine the mechanism of magnetization change. A stripe domain pattern with 180° domain walls changes into a small perpendicular stripe pattern as a result of the application of both a magnetic field and compression, and the density of stripes changes as a result of compressive stress.

Effect of stress on tertiary recrystallized silicon iron

The effects of stress on the magnetization change for tertiary recrystallized silicon iron has been investigated. The processes of magnetization change due to tensile stress at various points on the hysteresis curve have been made clear. This material has an extremely small volume portion of 90° domains compared with high-grade commercial grain-oriented silicon iron sheet.

Decrease of magnetization in positive magnetostrictive material due to tensile stress

The decrease of magnetization in positive magnetostrictive materials has been investigated. The magnetization change due to tension on grain-oriented 3% SiFe and non-oriented silicon iron sheets with materials of various silicon content has been measured. The reason for Villari reversal has been shown by the combination of two amorphous ribbon samples with positive and negative magnetostriction.

方向性薄けい素鋼の磁化過程とヒステリシス特性

Thin-gage grain-oriented silicon-iron sheet is expected as a low power loss core material in the future. With lowering thickness the hysteresis loss tends to increase while the eddy current loss decreases. It is important to suppress the increasing tendency of hysteresis loss to realize thin-gage silicon-iron with low power loss. In this paper the mechanism of the thickness dependence of hysteresis loss in (110)[001] oriented silicon-iron was discussed on the basis of the analysis of magnetization process and the experiments using single crystal specimens. It was revealed that the magnetization jump which occurs as a result of the magnetostatic interaction of surface free pole causes a great increase of hysteresis loss at lower thickness when the tilt angle of [001] axis out of the surface is large. The role of the surface closure domain on hysteresis loss was also studied.

Model of Secondary Recrystallization in Silicon-Iron and Comparison With Experiments

A comparative analysis has been made of selective grain growth processes at different layers of a grain oriented silicon iron sheet. Shorter incubation time and best orientation selection during secondary recrystallization appear at 40 μm from the sheet surface. This has been linked to the presence of a relatively strong //RD fiber in the texture. The differences through the sheet thickness are assumed to be inherited from the hot band. Computer simulations in the framework of the statistical theory of grain growth support the proposed selection mechanisms.

Application of the single-crystal 3% silicon-iron sheet to bridge-connected magnetic circuit

Application of a single-crystal 3% silicon-iron sheet with A rectangular B-H loop and very high induction to a bridge-connected magnetic circuit is described. The maximum flux value of the silicon-iron sheet in the magnetic circuit is controlled by the DC current. Utilizing this feature, a parametric transformer with variable output voltage was developed. The transformer is described. >

Investigations of silicon iron sheets by means of permalloy magnetoresistive sensors

The paper presents the results of application of permalloy thin film magnetoresistive sensors for investigation of silicon iron sheets. The following parameters have been measured - the single point value of magnetic field intensity and anisotropy, sheet texture, losses and uniformity. Determination of these parameters has been based on the measurement of stray field at the sheet surface.

The application of permalloy magnetoresistive sensors for nondestructive testing of electrical steel sheets

This paper presents application of a new sensor (permalloy magnetoresistor) for nondestructive investigations of silicon iron sheets. The principle of the measurement, arrangement of the transducer, operating conditions and examples of investigations results have been described. The presented method has been based on the measurement of stray field above the sheet surface. Following parameters have been determined: magnetic field intensity, losses, anisotropy, magnetisation, demagnetising factor, quality.

Crystal Orientation and Magnetic Properties in Thin-Gauge Silicon-Iron Sheets

The dependence of magnetic properties on sheet thickness of polycrystal thin-gauge silicon-iron sheets was studied under application of tensile stress. It was confirmed that iron loss decreases as crystal orientation improves at low thicknesses. Application of high tensile stress in the thin-gauge range does have an effect in reducing hysteresis loss.

Production of single-crystal 3% silicon-iron sheet with orientation near (110) [001

The production of single-crystal 3% silicon iron sheet with a near (110) [001] orientation was studied. This study presented the possibility of the industrial production of grain-oriented 3% silicon steel with very high induction. This production is characterized by a unique grain-growth inhibition system for promoting secondary recrystallization. The system is composed of final annealing in a temperature gradient. Final annealing in a temperature gradient above 3°C/cm enables production of grain-oriented 3% silicon steel with a very high induction of 2.0 T.

Effect of sulphur content in coating on development of (110)[001] texture of thin silicon–iron sheets

Good magnetic properties in thin (0.05 mm thick) strips of Fe-3 wt-%Si alloy can be obtained by secondary recrystallization to produce the (110)[001] texture, the grain growth inhibition, after termination of primary recrystallization, being brought about by FeS and MnS precipitates formed in the course of sulphur diffusion from the coating. The sulphur content of the coating and the limits within which it will ensure the production of wholly textured strips has been determined

Effects of bending on G.O. silicon iron sheets

The paper discusses effects of bending on domain configurations and losses of HI-B sheets with stress coating. Two-dimensional loss topograms were determined using a new test system based on raster-scanning the specimen surface with a thermistor. For longitudinal bending, considerable loss increases resulted. Transverse domains were generated on the concave and annihilated on the convex side respectively. In accordance with theoretical considerations, effects were contrary for transverse bending. Demagnetization of bended samples resulted in widening of wide main domains.

On the effect of grain size precipitated Al 2O 3 particles and lamination thickness on anomalous excess losses in non-oriented silicon iron sheets

On the effect of grain size precipitated Al 2O 3 particles and lamination thickness on anomalous excess losses in non-oriented silicon iron sheets

Influence of stacking on orientation direction in SiFe lamination

Measurements of power losses and some magnetic properties versus roll direction for different stackings were performed on grain-oriented silicon-iron sheets. The measurements were made using an ac compensated permeameter, an Epstein frame and a Mössbauer spectrometer. Observed experiments show that considerable cooperative effects exist between sheets in X stacking.