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It has been shown that locally measuring coercive force $${{H}_{{\text{c}}}}$$ based on the magnitude of demagnetizing current has a fundamental limitation on the measurement range. We have demonstrated the expediency of measuring coercive force in ferromagnetic objects locally, based on the magnitude of the tangential component of the magnetic field in the interpole space on the surface of the test object, that is, based on the internal field. This allows one to expand the range of measured values $${{H}_{{\text{c}}}}$$ by several times. Also, the influence of the gap between the transducer and the object, as well as the shape and size of test objects on the measurement results is significantly reduced. This makes it possible to measure the absolute values of $${{H}_{{\text{c}}}}$$ of homogeneous ferromagnetic objects, as well as the coercive force of objects with nonferromagnetic coatings of considerable thickness.

It has been experimentally established that a change in the temperature of samples made of steels widely used in engineering in the range of –10 to +40°C leads to a considerable change in the magnetic properties of these steels. With increasing temperature, the area of the hysteresis loop increases. The coercive force and remanence increase with the saturation magnetization value remaining practically constant. The value of maximum magnetic susceptibility also grows. The greatest change in properties is observed in steel 10 880, which is close in composition to technical ferrum. The established changes in the magnetic properties should be taken into account when conducting magnetic testing under climatic (natural) conditions.

Based on experimental research, a relationship has been established between the critical fields, which are determined by the shape of the magnetization curve and major hysteresis loop of bulk samples of iron–carbon alloys, with the magnitude of a positive maximum of magnetostriction in these samples. By varying the annealing temperature of cold-deformed 20G steel, it has been shown that the studied critical fields are much more sensitive to changes in the stress-strain state than the known coercive force and residual induction.

It has been shown both theoretically and experimentally that as the tempering temperature of quenched low-carbon steels increases up 600–650°C, the values of induction on the asymmetric “coercive return–magnetization” cycle decrease monotonically at fixed, proportional to the coercive force, values of magnetic field. This effect is associated with a transition from structures with a uniaxial magnetic anisotropy (after quenching) to structures with three easy-magnetization axes (after hightemperature tempering). Within the model of prevailing 180° displacements, numerical estimates have been produced for the magnetic parameters of the “coercive return–magnetization” cycle in these magnetic structures. The estimates are in a good agreement with experimental data. It is shown that induction resulting from the inversion (polarity switching) of coercive field exhibits a structural sensitivity that is similar to that demonstrated by coercive-return magnetization and is therefore a promising parameter for magnetic structural analysis. It has been demonstrated that the proposed parameter can be measured locally using the DIUS-1.15M mobile hardware-software system.

It is shown that by measuring the magnetic field in a specially shaped hole made in the magnetic circuit of a measuring transducer and the tangential component of the magnetic field in the transducer’s interpolar space near the surface of an object being magnetized, it is possible to locally determine the relative values of the magnetic properties of the test-object substance. The physical rationale is provided for a technique that makes it possible to determine the entirety of hysteresis characteristics and significantly expand the ranges of measurement of magnetic properties. The difference is established between the structural sensitivities of magnetic properties locally determined in terms of “flux–internal field” (the properties of matter) and “flux in the product–current in the windings” (the properties of “body”) coordinates. It is shown that it is possible and expedient to simultaneously measure and jointly analyze the magnetic characteristics of matter and “body”. Information is provided on the DIUS-1.15M mobile hardware–software system, intended for implementing single- and multiparameter techniques of monitoring the structure–phase and stress–strain states of ferromagnetic materials and objects based on the proposed measurement procedures.

The instability of the results of passive (in “geomagnetic” fields) magnetic testing under action of uncontrolled inhomogeneous fields is demonstrated. The zero crossing of the normal magnetic-field component that is suggested as a diagnostic sign of a stress-deformed state is formed independently of the structural-phase or stress-deformed state of a ferromagnet, and the position of such crossing alters even by small inhomogeneous fields. It is shown that the frequently encountered necessity for a multiparameter testing can be due to both the nonlinearity of relationships between controlled and measured parameters of testing and the necessity of taking into consideration measurement conditions. The main criteria are formulated that should be met by promising multipurpose systems of active (i.e., involving deliberate action upon test objects by quasistatic or variable field) electromagnetic testing.

The structure and strength and the magnetic properties of 32Х06Л steel subjected to quenching and tempering at different temperatures are studied. Based on statistical-modeling and experimental results, it has been established that coercive-return induction is a suitable parameter for controlling hardness. Another parameter, coercive force, can be used for estimating the phase composition of material. Local measurements of suggested testing parameters are possible with portable magnetic-measurement hardware–software systems of the SIMTEST-2 type.

A complex of magnetic and magnetoacoustic properties of cold-deformed and annealed (at different temperatures) steels with carbon contents of 0.2 (20 steel) and 0.7% (70 steel) was investigated. It was established that as the annealing temperature of these steels increases up to 700°C, the values of the parameters that are related to the intensity of irreversible magnetization-reversal processes monotonically increase. It is shown that the coercive force of 70 steel changes nonmonotonically under variations in the annealing conditions and cannot be a testing parameter. Among quasi-statically measured magnetic parameters for testing the annealing procedure, the residual induction and the coercivereturn induction can be used. The structural sensitivities of such parameters of the magnetoacoustic emission (MAE) as the amplitude, the fundamental frequency, and the field of the MAE maximum were investigated. It is shown that the MAE maximum amplitude and field correlate with the residual magnetic induction of the substance of the investigated steels and can be used in the diagnostics.

A brief history of the Russian Journal of Nondestructive Testing (in Russian, Defektoskopiya) is given, together with the journal’s current indicators and development program until 2020.

The possibility of testing the hardness of quenched and tempered medium-carbon steels using their magnetic properties is studied. It is shown that the two-parameter method should be applied for the reliable estimation of the hardness. The coercive return magnetization (induction) and the coercive force must be used as the basic and subsidiary parameters of testing, respectively. It is established that the content of carbon in steel influences the sensitivity of testing. It is shown that the suggested magnetic hardness testing method can be practically implemented with the use of the modernized SIMTEST-2.10 system.

The field and magnetic-inductance spatial distributions in plates that differ in geometric dimensions and magnetic properties, which were magnetized locally by U-shaped electromagnets of different standard sizes, were calculated using the finite element method. The magnetic-flux side scattering, which impedes the magnetization, was estimated qualitatively. Recommendations on designing magnetizing instruments, which are characterized by low side scattering, are given.