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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, 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]

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]

Conventional manufacturing processes cause plastic deformation that leads to magnetic anisotropy in processed materials. A deeper understanding of materials characterization under rotational magnetization enables engineers to optimize the overall volume, mass, and performance of devices such as electrical machines in industry. Therefore, it is important to find the magnetic easy direction of the magnetic domains in a simple and straightforward manner. The Magnetic easy direction can be obtained through destructive tests such as the Epstein frame method and the Single Sheet Tester by taking measurements in regions of irreversible magnetization usually called domains. In the present work, samples of rolled SAE 1045 steel (formed by perlite and ferrite microstructures) were submitted to induced magnetic fields in the reversibility region of magnetic domains to detect the magnetic easy direction. The magnetic fields were applied to circular samples with different thicknesses and angles varying from 0° to 360° with steps of 45°. A square sample with a fixed thickness was also tested. The results showed that the proposed non-destructive approach is promising to evaluate the magnetic anisotropy in steels independently of the geometry of the sample. The region studied presented low induction losses and was affected by magnetic anisotropy, which did not occur in other works that only took into account regions of high induction losses. [ABSTRACT FROM AUTHOR]

Abstract: An investigation was carried out to analyze and quantify the mechanical property changing mechanism of high speed steel by pulsed magnetic treatment. Specifically, a pulsed magnetic treatment system was designed and applied to the tool material treatment. The micro-hardness and red hardness were measured to quantitatively investigate the influence of magnetic treatment on the mechanical properties. Results showed that high speed steel material possessed better mechanical properties using the proposed pulsed magnetic treatment, of which the maximum increase of micro-hardness was 50HV. Also, the red hardness with low temperature could be improved. Moreover, the influence of magnetic treatment conditions on the micro-hardness change rate was investigated. It was shown that the micro-hardness change rate first increases and then stabilizes with the increase of magnetic field intensity, and it decreases with the increase of magnetization time. Ultimately, the dislocation densities were calculated by XRD data analysis according to the Williamson–Hall method and the interaction between magnetic field and dislocation was discussed in detail. Results revealed that the dislocation density of high speed steel material increased by 24% after pulsed magnetic treatment. The dislocation multiplication and motion induced by magnetic field led to the increase of dislocation density, which was the main reason of the increase in micro-hardness. The dislocation pile-up mechanism was responsible for the treatment effects of different magnetic treatment conditions. The dislocation configuration determined from TEM micrographs was in good agreement with the X-ray results and the discussion of dislocation mechanisms. [Copyright &y& Elsevier]

The effect of various combinations of conditions, i.e., presence of the Earth's magnetic field during and after deformation on the distribution of stray magnetic field of S355 steel sample, which is locally deformed, was investigated. Some of the stages of the experiment were carried out in zero magnetic field. Compensation of the Earth's magnetic field was obtained by the application of a pair of Helmholtz coils. These coils are able to produce homogeneous field compensating Earth's magnetic field over the full length of the sample. Stray magnetic field measurements were carried out along the longest dimension of the sample using the probe consisting of mutually perpendicular sensors allowing the simultaneous measurement of two magnetic field components, i.e., tangential and normal to a surface of the sample. Research has shown that there is a correlation between the level of plastic deformation of the investigated sample and the distribution of stray magnetic field. It was found that the nature of stray magnetic field of the sample depends on presence of external magnetic field during unloading. An attempt was also made, with the finite-element analysis, to verify experimentally obtained stray magnetic field distribution of undeformed sample. [ABSTRACT FROM AUTHOR]

This paper deals with a new analytical parametric magneto-dynamic model of a thin soft magnetic steel sheet (SMSS). The interdependence of the magnetic field and eddy currents inside such an SMSS is calculated by dividing the sheets into an arbitrary number of slices. Using an adequate number of slices, the magnetic field and eddy currents are described piece-wise uniformly across the SMSS for a given excitation dynamics. Dynamic hysteresis loops for arbitrary excitations can be calculated using the proposed model. The calculated results are validated by the measurements on a non-oriented SMSS. [ABSTRACT FROM AUTHOR]

Abstract: Numerous machine components are constantly subject to different magnetic fields mainly due to the environments they are in, and they show some wear process throughout their life time. To understand this wear process better, the effect of magnetic field on the tribological properties of AISI 4140 steel has been investigated by applying different magnetic field intensities. One of the important factors affecting the wear and friction properties of a tribological system is wear debris and their properties like chemical structure and movement between mating bodies. For this respect, magnetic field was applied on a ferromagnetic material both before and during wear tests. Then, tribological properties of the samples magnetized before the wear tests were compared with the samples to which magnetic field was applied during the tests. It was observed that samples subjected to the magnetic field during tests showed better wear resistance and lower friction coefficient values than the others as the magnetized wear debris produced during test could be removed between mating bodies by means of magnetic effect while oxidized debris were held at the rubbing interface and lowered the debris production. [Copyright &y& Elsevier]

The influence of stresses on the magnetic properties of nonoriented electrical steels was studied. The dependence of iron loss on compressive stress was affected by grain size. The magnetic polarization J in strong magnetic fields such as 5000 and 10,000 A/m increased due to compressive stresses and decreased due to tensile stresses in samples with low Si content. Using Kerr-effect domain observation, it was found that the reduction in J caused by tensile stresses was attributable to residual striped domains. Magnetostriction measurements in strong magnetic fields indicated that the increase in J under compressive stresses originated from the Villari effect (inverse magnetostrictive effect) due to negative magnetostriction in low-Si materials. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 182(4): 10-18, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22320 [ABSTRACT FROM AUTHOR]

In this paper, we calculate the electric cell voltage of the physical circuit at etching of ferromagnetic electrode in the form of a cylinder in an electrolyte caused by inhomogeneous distribution of concentration of the paramagnetic corrosion products on the surface of a steel cylinder in an inhomogeneous magnetostatic field. The shape of the electrode was chosen because all points of the cylinder surface are equivalent in this model system in the absence of magnetization and effects of the magnetic field can be easily separated from the effects of a different nature. The current density and Lorentz force are calculated in an electrolyte in the vicinity of the magnetized steel cylinder. The Lorentz force causes movement of an electrolyte perpendicular to the direction of the external magnetic field along the cylinder axis. Comparison of calculations with experimental data allows concluding that a certain part of paramagnetic ions in the electrolyte in a magnetic field represents the nanoclusters of paramagnetic ions, which can be for example nanobubbles. The results of the theoretical modeling can be used for creating functional materials by means of magnetoelectrolysis and for modeling of the influence of the biogenic magnetic nanoparticles on transport processes and biochemical reactions in cells of live organisms [ABSTRACT FROM AUTHOR]

To describe the vector magnetic hysteresis phenomenon of electrical steel sheets, an improved vector Jiles-Atherton hysteresis model is presented. The proposed model is developed based on Berqvist model. First, the anhysteretic magnetization function is improved by modifying the model parameters according to the excitation direction. By this, the modeling results are accurate under different alternating and nonsaturated rotating excitations. Furthermore, to model the magnetic property under saturated rotating excitations accurately, the proposed model is extended by modifying the model parameters according to the measured data. The proposed model is validated through comparisons between modeling and measured results under different alternating and rotating excitations. [ABSTRACT FROM AUTHOR]

Abstract: For investigating the magnetic abnormality influenced by stress in ferromagnetic materials, static tension tests on a case-hardened steel were carried out. Different loads, which covered tensile elastic loads up to plastic deformation and break, were applied. Meanwhile, the normal component of magnetic flux leakage, H p(y), was measured by metal magnetic memory testing. The results indicate that H p(y) values change with the tensile loads and positions. There exists a relationship between k, which is the inclination of the linear amplitude-locus magnetic flux leakage curve, and static tension load. A simple model is derived. Additionally, the mechanism of the magnetic memory effect can be explained by the theory of the interaction between dislocations and domains. The research provides the potential possibility of quantitative inspection for metal magnetic memory testing. [Copyright &y& Elsevier]

In this paper, stress and fatigue-loaded ferromagnetic steel samples were evaluated using three different remanent flux leakage transducers. Giant magnetoresistive sensors were used as the pickup elements. Each transducer has its own integrated local magnetizing section, which allows us to magnetize the tested material in different directions. The defect detection dependency on angle, at which it occurs to the magnetizing field and sensing element, is minimized by gathering and then integrating the information from transducers. The performance of the transducers was verified using a steel plate (S355J2G3) with electro-discharge machined notches. Further experiments were carried out using fatigue and stress-loaded steel samples. [ABSTRACT FROM AUTHOR]

Abstract: The effect of magnetic field with different intensities on fatigue life of AISI 4140 steel has been investigated. For this purpose, unnotched and notched specimens were prepared from AISI 4140 steel. It was obtained that when the magnetic field especially was applied to the specimens at the stage of fatigue crack initiation, the fatigue life improved by reason of delaying formation time of slip bands due to regular direction and distribution of magnetic domains. And, it was observed that magnetic field was applied from the beginning of fatigue test up to occur the fatigue fracture, it was detrimental on the fatigue life because of over heating of the specimens. [Copyright &y& Elsevier]

The mechanical and magnetic properties of 50KhGFA laminated spring steel are investigated in different regimes of the quenching and tempering temperatures. It is shown that the quality of heat treatment of this steel cannot be tested using any standard magnetic characteristic. It is proposed to test the mechanical properties of 50KhGFA steel by measuring the amplitude of pulses driven a magnetized product into the demagnetized state or using the gradient of the remanent magnetization field after pulse magnetization to saturation and remagnetization by magnetic field pulses of a constant amplitude. [ABSTRACT FROM AUTHOR]

Focuses on a study which examined the modeling of thin steel shells placed in a static magnetic field. Behavior of the sheet; Information on global formulations; Conclusion.

Presents information on a study which developed a mathematical model for magnetization changes in a steel rod under varying torsion in a constant applied magnetic field. Extension to the law of approach to torsional stress; Changes in the energy balance equation; Details on energy balance formulation for torsional stress.

Measures the conventional magnetic parameters and Barkhausen noise in pressure vessel steel samples. Three stages in neutron dose variations; Deterioration of mechanical properties brought by neutron irradiation.

The author discusses aspects of trapped field magnets or superconductor magnets that can shape the technologies in various fields of engineering. He refers to the study by Durrell and colleagues on a world-record trapped field with a bulk of superconducting compounds for steel reinforcement. The author agrees that superconductor magnets can create ubiquitous magnetic fields in various applications including water purification, drug delivery systems, and superconducting motors.