The influence of the magnetoelastic effect on the hysteretic properties of medium-carbon steel during uniaxial loading

Hysteretic magnetic properties and longitudinal magnetostriction of planar specimens of air-hardened 45 steel were measured as functions of elastic tensile stresses along and perpendicular to the applied loading using a closed magnetic circuit and attachable transducers. Parameters that exhibit monotonic variations with increasing elastic tensile stresses, were found. It was shown that the maxima that were observed in the dependences of residual inductance and relative maximum magnetic permeability on applied stresses, as well as the minima that were observed in the dependences of the coercive force and demagnetizing current of an attachable electromagnet as measured with a sensor arranged along the tension axis on applied stresses, are related to the behavior of the magnetostriction curves of the steel under study.     

Effect of elastic deformation by compression,tension, and torsion on the critical magnetic field distribution in a steel 15XH4Д

Effect of deformation by compression, tension, and torsion on magnetic characteristics and critical magnetic field distribution in a high-strength economically alloyed structural steel 15XH4Д. The coercive force, residual induction, and maximum magnetic permeability vary definitely with changing stresses. This fact gives the principal possibility to use these characteristics as parameters for magnetic testing of elastic strains. Moreover, the studies of critical magnetic field distribution allow us to obtain data on the volume of the ferromagnet, which has changed its state in a given magnetic field under certain mechanical stresses.     

Effect of Structural-Phase Composition on Magnetic Properties of Iron Powders Ground in Carbonaceous Medium Doped with Surface-Active Substance

In the process of intense grinding of iron powders in heptane with addition of oleic acid, the particles' dimensions reduce, their shapes change, and the particles are saturated with carbon, oxygen, and hydrogen atoms, which diffuse to the regions of mosaic block boundaries and form weakly ordered clusters and iron-based phases. The coercive force increases from 8.5 to 92 A/cm as a result of grinding. In the process of anneal, ordered phases Fe₃C and Fe₃O₄ are produced from disordered clusters and phases, which leads to an increase in the coercive force to 220 A/cm.     

Physicomechanical properties and structure of the powder materials of the Fe-Si system

The integrated study of the structure and magnetic, electrical, and mechanical properties of the Fe-Si powder materials in a range of silicon concentrations 0–12 wt % showed that the dependence of all physicomechanical properties of these materials on the silicon content was related to the sequence of the formation of the disordered silicon solution in iron, ordered solution, and the Fe₃Si phase.     

An Effect of Nonferromagnetic Gaps on the Magnetic Properties of Stacks of Steel Plates with Different Values of Magnetic Hardness: II. An Attachable Electromagnet

Stacks of steel plates that have different values of magnetic hardness and are interlaid with nonferromagnetic inserts were investigated by a magnetic-measurement device with an attachable electromagnet. The coercive force and the residual induction were shown to depend, similar to the case of a closed magnetic circuit, on the layout of plates in a stack and on the thickness of nonferromagnetic inserts between these stacks.__________Translated from Defektoskopiya, Vol. 41, No. 3, 2005, pp. 63–73.Original Russian Text Copyright © 2005 by Gorkunov, Povolotskaya, Mitropol’skaya.Dedicated to the Anniversary of the 100th Birthday of Corresponding Member of the Russian Academy of Sciences M. N. Mikheev     

Demagnetizing Factors of Ferromagnetic Bars upon Magnet Saturation

Peculiarities of magnetization of ferromagnetic bars in a magnet-saturation regime are considered. By an example of a model specimen made of an isotropic ferromagnet in the form of infinitely long bar having a rectangular section and magnetized in a transverse magnetic field, calculations of magnetic parameters for a central section of the body are performed. It is shown that, as the magnet saturates, the central demagnetizing factor of ferromagnetic bars of any relative length always exceeds the demagnetizing factor of a uniformly magnetized bar because of the “ rotational” magnetization of the material.     

Structure and mechanical properties of a high-carbon steel subjected to severe deformation

The structure and mechanical properties of a high-carbon eutectic steel subjected to the cold plastic deformation by hydrostatic extrusion in a wide range of true strain have been studied. Using scanning and transmission electron microscopy, it has been shown that the formation of cellular, fragmented, and submicrocrystalline structures occurs in the ferritic constituent of the pearlite structure of the steel upon extrusion. This is a consequence of the occurrence of dynamic recovery and continuous dynamic and post-dynamic recrystallization, which cause a decrease in the density of free dislocations at the true strain of more than 1.62. The partial dissolution of the carbide phase is also observed. It has been found that, at a true strain of up to 0.81, the strength properties of the investigated steel are determined mainly by subgrain, dislocation, and precipitation mechanisms of the strengthening; in the deformation range of 0.81–1.62, the role of the grainboundary strengthening increases. At strains above 1.62, grain-boundary strengthening is a prevailing mechanism in the formation of the level of strength properties of the extruded U8A steel. The ultimate tensile strength and yield stress over the entire strain range only uniquely correlate with the density of highangle boundaries; the dependences of the strength characteristics on other structural parameters are not monotonic.     

Estimation of the quality of strengthening frictional treatment and subsequent tempering of eutectoid steel by the eddy-current method

The possibilities of the electromagnetic eddy-current method for evaluating the structural state and depth of strengthened layers on the surface of hardened and low-tempered steel U8 subjected to plastic straining using a hard-alloy indenter and subsequent heat treatment (tempering at T = 100–600°C) have been studied.