Magnetostriction and Magnetization of Common High Strength Steels (original) (raw)
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2014
Research was carried out with a view to developing a methodology and algorithms for the determination of the stress-strain state of a ferromagnetic component based on measurements of magnetic properties. The aim of the testing was to define the stress-strain state, both as the effect of active stresses resulting from load and after unloading. The studies involved an analysis of changes in the residual magnetic field (RMF) and in the Barkhausen effect caused by the magnetic field (MBE). Good quantitative relationships between active stresses and the number of counts, which is one of the parameters that describe the MBE quantitatively, were found. It was also found that the MBE number of counts could be used as a diagnostic signal to develop correlations for the evaluation of the hardness of some ferromagnetic steels. A method for the evaluation of the first order residual stress in ferromagnetic steels based on residual magnetic field measurements was presented. The values and distri...
Assessment of the Stress Sensitivity of Magnetostriction in Grain-Oriented Silicon Steel
IEEE Transactions on Magnetics, 2000
This paper describes a novel, versatile system for measuring the stress sensitivity of magnetostriction of Epstein strips of grain-oriented electrical steel, an analysis of results of measurements on several grades of commercial material, and an attempt to relate their stress sensitivity characteristics to material properties. The maximum value of peak magnetostriction under applied stress is proportional to the strip gauge for both conventional and high permeability grades of material. A model explains the contributions of retained stress and stress due to the forsterite coatings on grain-oriented silicon steel. This model can be used to correlate the thickness of the fosterite coating to its calculated coating stress. It is also possible to separate the effect of the phosphate and forsterite coatings. Both types of coating set up a longitudinal stress in the steel in proportion to their thickness.
Newly Developed Systems for the Magnetostrictive Materials Strain Measurements
Magnetostrictive effect is connected with changes of the dimension of soft magnetic materials during the process of theirs magnetization. The paper presents newly developed measuring systems for testing of the strain distribution in the magnetostrictive materials. The system uses simultaneously two measurement techniques: strain-gauge sensor for local strain measurement and grating interferometry for the global determination of strain distribution.
Journal of Magnetism and Magnetic Materials, 2000
The design of an automated system for the rapid assessment of the AC magnetostriction in electrical steel sheet under linear applied stress in the range $10 MPa is described in detail. Typical results are presented showing the e!ect of induction on the unstressed material together with plots of the harmonics of magnetostriction and speci"c total loss versus applied stress.
2012
9 Deformation of the ferromagnetic material, known as magnetostriction, causes 10 vibrations and noise of electrical machines and transformer cores. A setup by using 11 heterodyne laser interferometers has been built to measure the magnetostriction strains 12 as a function of the applied magnetic field. The measurement results on a sample of 13 nonoriented electrical steel are presented in this work. These results are compared with 14 those obtained by using a strain gauge setup. The laser measurements are less disturbed 15 by noise, especially for measurements under low amplitude magnetisation. In addition, 16 contrary to the strain gauge samples, the sample preparation for the laser setup does 17 not require removal of the protective coating. Measurement results on the coated 18 samples are highly helpful for the calculation of the magnetostriction noise of the 19 device. The coated samples show smaller deformation, since the coating applies tensile 20 stress to the material. For ...
Measurement and Modeling of 2-D Magnetostriction of Nonoriented Electrical Steel
IEEE Transactions on Magnetics, 2000
Magnetostriction of nonoriented electrical steel was measured under rotating flux magnetization conditions which occur in AC electrical machine stator cores, and compared with the magnetostriction calculated from a model based on a mechanical elasticity analogy. Shear magnetostriction and magnetostriction perpendicular to the magnetization direction are accounted for in the model which leads to an accurate representation of magnetostriction throughout the electrical steel lamination plane. This has the potential for improving the accuracy of stator core deformation and vibration calculations.
red.pe.org.pl
Surface domain patterns in electrical steel, which appear under rotational magnetisation, were noted to be comparable to those which are observed under high compressive stress. This paper presents comparison of peak to peak magnetostriction of Epstein strips under high compression magnetised along rolling and transverse directions, and disc samples under rotational and uniaxial magnetisation with no external stress applied. Good correlation was found between magnetostriction measurement results obtained in the rolling direction of non-oriented Epstein strips under high compression and disc samples under rotational magnetisation. Also it was observed that the rotational magnetostriction of grainoriented electrical steel is greater than its uniaxial value under compressive stress. Streszczenie. Artykuł prezentuje porównanie magnetostrykcji pasków Epsteina magnesowanych wzdłuż i prostopadle do kierunku walcowania (podanych naprężeniu) oraz próbek w formie dysku poddanych magnesowaniu osiowemu i rotacyjnemu (bez naprężenia). W przypadku blach niezorientowanych znaleziono korelację między magnetostrykcją w kierunku walcowania oraz stratami przy magnesowaniu rotacyjnym. W przypadku blach zorientowanych magnetostrykcja rotacyjna była większa niż jednoosiowa przy naprężeniu próbki. (Porównanie jednoosiowej i rotacyjnej magnetostrykcji blach elektrotechnicznych zorientowanych i niezorientowanych)
Capacitance bridge measurements of magnetostriction
Journal of Applied Physics, 2002
Magnetostriction effects were investigated for three different materials by using a simple, reproducible, and cost-effective method recently developed in our laboratory. The magnetostriction effects were generated by a large oscillating magnetic field produced by a high current 60 Hz ac welder power supply, capable of reaching saturation levels for the material, and then detected by a change in capacitance between a hollow cylindrical sample and a concentric brass ring. This capacitance change was continuously monitored at a high frequency rate by a standard laboratory capacitance bridge meter. The output voltage of the bridge was fed into a storage cathode-ray oscilloscope and its voltage versus time signals were then analyzed by a computer program. Two ferromagnetic rings, constructed of high-speed steels 4620 and 4340, which have proven applicability for use in magnetoelastic torque sensing, were used as the samples for investigating the magnetostriction effects, while a paramagnetic aluminum ring was used for the control sample. Our study showed that the 4340 ring, which had higher nickel, cobalt, and chromium content than that of the 4620 ring, had the largest magnetostriction effect, and that the aluminum ring displayed no magnetostriction effect, as was expected. We have found this experimental method to be both reproducible and sufficient to rank different ferromagnetic materials by their magnetostriction level, which is a significant consideration in producing effective magnetoelastic torque sensors.