A. M. Povolotskaya

The influence of an elastic uniaxial deformation of a medium-carbon steel on its magnetostriction in the longitudinal and transverse directions

In order to reveal the role of magnetostriction in the formation of a magnetic texture that appears in steels during their elastic deformation, the influence of stresses during uniaxial loading on the behavior of several magnetic characteristics of medium-carbon steel 45 was investigated. The magnetic parameters were measured under the conditions of a closed magnetic circuit with the application of attachable transducers along and across the direction of the applied load. The results of measurements of the hysteresis and magnetostriction properties of the investigated steel were compared. The magnetic parameters that monotonically change with an increase in the applied stresses were established.

The application of magnetic structural phase analysis for the diagnostics of the State of a 08X18H10T Steel-Ct3 Steel composite material and its components that were subjected to plastic deformation

The use of composite, in particular, multilayer materials, is one way to decrease the specific quantity of metal in an item and to increase its service characteristics. To develop methods for the diagnostic of the state of such composite materials and their components, the effect of cold rolling on the structure, magnetic, and mechanical properties of a two-ply composite material and its separate components was studied; the material was prepared by explosion welding of austenitic corrosion-resistant and low-carbon steels. It was shown that magnetic characteristics can be used for estimating the degree of deformation by rolling, phase composition, and mechanical properties of both two-ply 08X18H10T Steel-Ct3 Steel composite material as a whole and its separate components.

The influence of a preliminary plastic deformation on the behavior of the magnetic characteristics of high-strength controllably rolled pipe steel under an elastic uniaxial tension (Compression)

The influence of a preliminary plastic deformation, which models the initial stressed–strained state (SSS) of an article, on the behavior of the magnetic characteristics of pipe steel of the X70 (K60) strength class under elastic tension and compression was investigated. The magnetic characteristics of specimens were measured both under the conditions of a closed magnetic circuit and using attachable transducers along and across the applied-load direction. The prehistory in the form of plastic deformation has an effect on the regularities in changes in the magnetic parameters of a material upon the next elastic deformation as a consequence of plastic-deformation-introduced residual stresses of different levels. This indicates the necessity to consider the initial SSS of a metal structure when developing magnetic methods for determining the parameters of their SSS during operation.

Coercive Force of a Package of Steel Sheets with Different Degrees of Magnetic Hardness

Samples in the form of packages of steel plates with different degrees of magnetic hardness have been studied. Coercive forces of the composite samples with different contributions of harder materials and different orientations of plates with respect to one another in open and closed magnetic circuits have been calculated.

Effect of Plastic deformation and its localization zones on magnetic characteristics of steel 45

Attachable transducers were used to measure the demagnetizing current, which is proportional to the coercive force, and Barkhausen noise parameters for steel 45 specimens depending on the degree of their plastic deformation in measuring the magnitudes along and perpendicular to the tension direction. The demagnetizing current measured along the preliminary tension direction was shown to increase monotonically; the rate of its changes is maximal at the initial stage of plastic deformation. The demagnetizing current measured perpendicular to the applied tension direction also increases monotonically but within a narrower range. Near local inhomogeneities formed during the deformation, substantial changes in the coercive force and Barkhausen noise take place. The results obtained are explained on the basis of the current concept of the anisotropy of internal stresses in preliminarily plastically deformed materials.

Coercive Force and Distribution of Critical Fields in Two-Layered Ferromagnets of Various Hardness. I. Toroidal Samples

The paper reports on a calculation of coercive forces in two-layered toroidal samples composed of rings with various magnetic hardness on the base of magnetic hysteresis loops characterizing materials of each component. Secondary spectra of magnetic hardness of two-layered samples, characterizing distributions of critical fields in the process of cyclic magnetization, have been investigated. A suggested method for estimating the fractions of harder and softer components in composite samples uses the secondary spectra of magnetic hardness.

The influence of elastic deformations on the hysteresis properties of a two-layer ferromagnet composed of components with magnetostrictions of opposite signs

The influence of an elastic deformation that is produced by an uniaxial extension (compression) on the behavior of several magnetic characteristics of Armco iron and nickel, whose magnetostrictions have opposite signs, and a two-layer material composed of them was studied. The magnetic characteristics were measured both under the conditions of a closed magnetic circuit and using attachable transducers along and across the direction of an applied load. The results are explained from the standpoint of the formation of magnetic anisotropy, which is induced by the action of normal stresses. The results of measurements of the hysteresis and magnetostriction properties of the investigated materials are compared. The magnetic parameters of the investigated materials that monotonically change with an increase in the applied stresses are determined.

Decrease in the effect of a gap on coercimetry results when taking the properties of an attachable transducer into account

A method that allows the effect of a gap on the results of coercimetric quality control of articles to be decreased that is based on taking properties of an attachable transducer into account is proposed. The properties of a transducer are taken into account using a preliminary recorded demagnetization line of an attachable electromagnet whose magnetic circuit is not closed by an article. It is shown that the tangential component of the magnetic field of an inspected article during magnetization reversal along this line equals the coercive force of the article if its cross section does not exceed the electromagnet cross section.

Estimating the deformation state of single-and two-layer ferromagnetic materials on the basis of their magnetic characteristics

Magnetic characteristics measured along and perpendicularly to the tensile-stress direction for single-and two-layer specimens made of steel Ct3cΠ and steel 45 that were subjected to various heat treatments are studied at different degrees of deformation. Measuring the magnetic characteristics perpendicularly to the tension direction is shown to be more informative from the point of view of estimating the degree of deformation, while the use of a four-pole transducer allows determination of the direction.

Comparative analysis of the magnetic characteristics of plastically deformed metal in different zones of a welded pipe under elastic deformation

Comparative analysis of the effect that the pre-history of plastic deformation by uniaxial tension has on the regularities in the behavior of some magnetic parameters of metal in different zones of a welded large-diameter pipe made of strength grade X70 steel has been carried out under the conditions of subsequent elastic uniaxial tension (compression).