V. A. Zakharov

Regularities of the change in the coercive force under biaxial asymmetric deformation of steel 3

The change in the coercive force under biaxial asymmetric (tension and compression in mutually perpendicular directions) cyclic deformation of cross-shaped steel 3 specimens in the elastic region of deformations was studied. Specimens were deformed beforehand under biaxial asymmetric loading to various degrees of plastic deformation. It was demonstrated that the elastic-deformation dependences of the coercive force measured along the tension and compression directions are qualitatively similar to those under uniaxial tension or compression. It was also shown that, under cyclic elastic loading, these dependences are reversible for well-annealed steel and have a hysteresis that expands with increasing degree of plastic deformation for plastically deformed steel. The possible causes of the hysteresis in the dependence of the coercive force on the elastic cyclic deformations under biaxial loading are discussed. It was supposed that the hysteresis of the coercive force was caused by the appearance of free (not bound in carbide phases) carbon atoms playing the role of interstitial impurity atoms for the α-iron lattice in plastically deformed carbon steels. The possibility of estimating the stressed-strained state of steel under biaxial loading using a magnetic method was discussed.

Coercive Force of Ferromagnetic Steels under the Biaxial Symmetrical Tension of a Material

Patterns of coercive force variations of Ct.3 and X70 ferromagnetic steels under biaxial symmetrical tension within both elastic and plastic ranges of deformation were studied using X-shaped specimens. It was shown that the coercive force of isotropic polycrystalline materials increased during plastic deformation under biaxial symmetrical tension and was proportional to applied stresses (loads). Plastic deformation of materials with high initial coercive-force anisotropy along the principal directions (X70 steel) leads to an abrupt decrease in anisotropy and subsequent alternation of its sign. The patterns of a material’s coercive force behavior allow the coercive force to be used for estimating the stress-strain state (from both an increase in the coercive force and its variations during loading as compared to that of the initial material) of articles made from the studied steels under biaxial symmetrical tensile deformation.

The influence of biaxial elastic deformation on the coercive force and local remanent magnetization of construction steels

The influence of biaxial elastic tension-compression and tension-tension deformation on the coercive force and remanent magnetization of Cτ3 steel and 09Γ2C pipe steel cross-shaped specimens is studied. It is shown that coercive force grows monotonically with increasing load in the direction of compression under elastic tension-compression deformation and almost does not change under elastic tension-tension deformation. The local remanent magnetization decreases for all the considered types of biaxial elastic deformation. The possibility of using these methods for the evaluation of the stressed state of complexly deformed carbon steel products is discussed.

Coercive-force hysteresis of carbon steels during elastic cyclic tensile deformation

Dependences of the coercive force and mechanical stresses on cyclic tensile in the region of elastic deformation of steel samples with various carbon contents (Armco iron, 3, 8) are investigated. It is shown that the dependence of the coercive force on cyclic elastic tensile deformation is reversible for well-annealed samples. The dependence for plastically deformed steels has a hysteresis loop that is significantly determined by the carbon content and increases with an increasing degree of plastic deformation. It is assumed that the hysteresis of the coercive force as a function of elastic cyclic tensile deformations in plastically deformed carbon steels is caused generally by the appearance “free” carbon atoms, i.e., those not bound in carbide phases, which act as interstitial impurity atoms in the lattice of α-iron.

Effect of Pore Shape and Pore Orientation on Internal Demagnetization Factor of Porous Ferromagnetic Materials

Taking as examples toroidal model samples with equal values of porosity, but with pores of different shapes, we studied the effect of porosity, pore shapes, and applied magnetic field on the internal demagnetization factor for porous magnetic materials. An empirical formula has been obtained for estimating the internal demagnetization factor of porous magnetics.

Peculiarities of Changes in the Desired Signal of a Magnetic Anisometer under Rotation of Its Attachable Sensor

The way the rotation and speed of the sensor in a permanent-magnet anisometer affect its readings when inspecting the stress-strained state of ferromagnetic articles has been studied. Regularities of changes in the longitudinal and transverse magnetic-field strength components during sensor rotation have been revealed. A degree to which both components depend on the rotation speed has been demonstrated.

Correlation of rail structure with the Rayleigh-wave velocity and the coercive force

The velocity of Rayleigh waves is correlated with the depth of the decarburized layer and the hardness of rail steel. With increase in the depth of the decarburized layer and decrease in the hardness, the velocity of Rayleigh waves increases. Conversely, in the same conditions, the coercive force of the rail steel declines. The thickness of the decarburized layer is determined by this method and confirmed by direct measurements.

Evaluating the Structure of a Ferromagnetic Material Based on Magnetic-Field Strength between the Poles of an Attached Two-Pole Magnetizing Device

The possibility for using a magnetic structoroscope with a two-pole permanent-magnet magnetizing device to test mechanical properties of stressed-deformed state of articles made of ferromagnetic materials has been investigated. Dependences of equipment readings on the geometrical dimensions of the structuroscope sensor and on the deformation of ferromagnetic material of a sample in tension in the elastic loading–unloading domain are presented for samples made of different ferromagnetic materials.

A magnetizing device of a scanning coercimeter

We describe a device that is designed for magnetizing articles during the testing of ferromagnetic objects with a scanning coercimeter. The problem of magnetizing an article at high velocities of movement of a magnetizing device and measuring the residual magnetic field above the article surface was solved. The results of experimental studies of the operation of a scanning coercimeter in a range of velocities of motion of the magnetizing device of up to 4 m/s are presented.