E. S. Gorkunov

Correlation between the stress-strain state parameters and magnetic characteristics of carbon steels

A method for reconstruction of the stress-strain diagrams of steel objects from their magnetic characteristics determined directly during tension has been suggested. The coercive force, residual induction in the major hysteresis loops, and the maximum magnetic permeability are recommended as parameters for nondestructive testing of stresses and strains.

Features of electromagnetic methods for testing the wear resistance of medium-carbon structural steel subjected to laser or bulk hardening and tempering

Features of applying attachable eddy-current transducers of two types (with a flat end surface and a protruding ferrite rod core with localities 5–6 and 3–4 mm in diameter, respectively) for testing the structural state, hardness, and abrasive wear resistance of structural steel 45X (0.45 mass % C and 0.85% Cr), which was hardened under the action of continuous laser radiation, have been studied. The feasibilities of the eddy-current and coercimetric techniques for evaluating the wear resistance of a medium-carbon steel subjected to laser or bulk hardening and tempering in the temperature range 75–600°C have been studied.

Structure, mechanical characteristics, and deformation and fracture features of quenched structural steel under static and cyclic loading after combined strain-heat nanostructuring treatment

In the work, we studied the special features of deformation and fracture of quenched steel 50 (0.51%) under static and cyclic tension after combined strain-heat nanostructuring treatment, which includes fictional treatment with subsequent tempering at 350°C. It is shown that the combined nanostructuring treatment of quenched steel 50 changes the character of plastic flow, making it more uniform, in the loaded material. Under static tension, this shows up as disappearance of the yield plateau early in the process, and under cyclic loading, as suppression of the deformation relief formed by shear and rotational deformation modes. Despite incipient cracks, the hardened surface layer thus escapes complete fracture throughout the fatigue loading and preserves its resistance to mechanical contact action.

Effect of friction-induced hardening on the features of magnetic and eddy-current behavior of an annealed structural steel under cyclic loading conditions

The effect of friction processing on the mechanical properties in uniaxial tension, the magnetic properties, and the electromagnetic characteristics of an annealed Steel 3 (St3) grade structural steel has been studied. It is established that the coercive force, residual magnetic induction, initial magnetic permeability, and eddy-current characteristics can serve as parameters for monitoring the quality of steel hardened by friction processing. Features of friction-induced changes in the strength, magnetic properties, and electromagnetic characteristics of St3 grade steel loaded in the region of low-cycle fatigue are revealed. It is shown that magnetic and eddy-current techniques can be used for monitoring the state of a friction-hardened surface layer of steel samples in the course of their cyclic loading.

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.

Eddy-current testing of the hardness, wear resistance, and thickness of coatings prepared by gas-powder laser cladding

The possibility of applying the eddy-current method to estimate the composition, hardness, abrasive wear-resistance, and wear resistance under sliding friction conditions of chromium-nickel and chromium-nickel-cobalt coatings prepared by gas-powder laser cladding was studied. Variations in the readings of an eddy-current instrument along the depth of the surface cladding layer and with changing thickness of coatings, which are due to the distribution of structural components in coatings and large differences between the electromagnetic characteristics of cladding layers and the ferromagnetic steel base of specimens, were determined. A technique of the eddy-current testing of the thickness of Cr-Ni and Cr-Ni-Co cladding coatings on a ferromagnetic steel base is proposed. It allows one to estimate the quality of the strengthening laser cladding and subsequent grinding, monitor the state of coatings under service conditions, and forecast the residual life of cladding elements subjected to intense wear.

Application of an Eddy-current method for the assessment of stored plastic deformation and residual mechanical properties after cyclic loading of an annealed medium-carbon steel

The effect of cyclic loading of annealed steel 45 during low-cycle fatigue on changes in its electrical characteristics is studied. In the region of both small and mediate strains, an eddy-current transducer signal is found to be highly sensitive to the plastic deformation stored during cyclic loading. Correlations between readings of an eddy-current instrument and the residual mechanical properties of the material after cyclic loading are obtained. The possibility of assessing the residual mechanical properties of the material during its cyclic loading is considered.

Barkhausen noise and its utilization in structural analysis of ferromagnetic materials (Review article V). 5. Effects of volume and surface thermal processing

The effects of both volume and surface thermal processing on the parameters of Barkhausen jumps, which are determined by the configuration of a magnetic structure and processes of irreversible displacement of domain boundaries is discussed. Structural changes in steels due to their thermal processing affect the parameters of Barkhausen jumps, which enables utilization of the Barkhausen noise in nondestructive testing of structural states in the steels. Specific examples of applications of this method and instruments for testing the quality of volume and surface thermal processing are given.

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.

Effect of Deviation from Coaxiality between the Directions of Magnetization and Mechanical Strain on the Results of Magnetic Testing of Elastic Strain in Steels

The magnetoelastic effect in steels that are in the states of coercive force and residual magnetization in the saturation hysteresis loop is studied. The regularities of changes in the residual magnetization and coercive force under uniaxial tensioning and compression of specimens of 30KhGSA steel magnetized along the direction of strain application are established. It is shown that a variation in the direction of magnetization and complication of the strain pattern result in considerable deviations in the character of changes in the magnetic forces determined by a ferroprobe-type coercive force meter for elastically strained plates from St3 and R6M5 steels and for an St3 beam.