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No 6 (2023)
Articles
Acoustic monitoring of steel production in the ladle-furnace unit
Abstract
A method of implementing acoustic control of the steel-making process in a ladle-furnace unit using a step-by-step acoustic event recognition model is proposed. The use of the developed model makes it possible to predict metal emissions with an accuracy of 96 %.
Defektoskopiâ. 2023;(6):3-10
3-10
Using a magnetic flux leakage method to estimate railway track bolted joint gaps
Abstract
The periodic estimation of the rail joint gap values allows evaluating the reliability of the continuous welded railway track and preventing its temperature deformations. The purpose of this study is to search for a simple and reliable way to evaluate the rail joint gap, which allows you to determine the desired values during high-speed inspection in automatic mode in a wide range of temperatures. A brief overview of existing techniques for evaluating rail joint gaps based on different physical principles is given. In the proposed technique, a magnetic flux leakage (MFL) method with the placement of electromagnets on the wheel axes of a car bogie is used. Such magnetization systems are applied recently on flaw-detector cars and provide a stable magnetic flux in the tested rails. Using a three-dimensional model of the rail segment with a bolt joint, we studied the characteristics of the magnetic flux leakage fields when changing the size of the rail gap in the entire practical range. The characteristics are selected that are most sensitive to a change in the gap and by which its value can be determined. With small values of the gaps the amplitude of the magnetic sensor signal is proposed as a main informative parameter, and with large gaps the estimation based on the distance between the signal extremums is more preferred. The results of computer modeling of the influence of the joint gap on the parameters of the magnetic signal qualitatively coincide with the results of field measurements made at inspection speeds up to 60 km/h.
Defektoskopiâ. 2023;(6):11-25
11-25
Analysis of influencing factors of electrostatic detection system based on double electrode
Abstract
This study aims to explore the influence of various factors of the electrostatic induction system on the object information of double-electrode electrostatic detection. Based on the principle of electrostatic induction, we first establish a system model and a mathematical model for single-electrode electrostatic detection. We analyze the effect of various factors on the target information of single-electrode electrostatic detection. On this basis, a novel double-electrode electrostatic detection model is introduced, and detection rational is explained in detail. A comparative study using theory and computer simulation is conducted. The results show that the novel double-electrode electrostatic detection system performs significantly better than its single-electrode counterpart. We also observe that the vertical detection distance has a greater impact on the detection performance compared to the interval between the two electrodes. Moreover, we find that the vertical detection distance and the interval between the two electrodes have a much more substantial influence on the electrostatic detection performance than other intrinsic factors.
Defektoskopiâ. 2023;(6):26-37
26-37
Thermal nondestructive testing: traditional approaches and novel trends (review)
Abstract
In the last years, thermal testing has shown up as a quickly growing nondestructive evaluation technique. This is explained by wide implementation of composite materials in many industrial spheres, first of all, aviation and aerospace. Inspection of composites by means of traditional nondestructive testing (NDT) methods encounters some difficulties, which can successfully be overcome by using thermal NDT. Moreover, an overwhelming progress in development and commercialization of infrared imagers also took place in the last two decades. On the basis of earlier reviews in the field of thermal NDT, the author has attempted to summarize recent achievements in this field, including inspection methodologies and data processing, as well as development of thermal NDT equipment and applications of this technique. The review describes both national achievements and international approaches, which have been lately proposed in thermal NDT thus making this technique a very promising in NDT of some classes of materials and constructions.
Defektoskopiâ. 2023;(6):38-58
38-58
Development of approaches to real-time optical diagnostics for laser weld formation process using laser emission spectroscopy
Abstract
Welding of metals is subject to various random processes that degrade the quality of the weld, ranging from the presence of inhomogeneities in the metal to spontaneously occurring pulsating processes. Pre-weld destructive testing cannot eliminate the presence of inhomogeneities and is ineffective for spontaneous deviations in the welding process. Therefore, the development of new approaches for real-time diagnosis of the laser welding process is particularly relevant today, especially with the widespread implementation of fiber lasers. The objective of this study was to develop approaches for optical diagnostics of the process of forming heterogeneous material based on laser emission spectroscopy. An experimental setup was created to develop approaches for optical diagnostics of the process of forming heterogeneous material, which is a critical task for additive technologies and laser welding. It was demonstrated that for industrially relevant aluminum alloys 1420, 1580, AMG (Russia), it is possible to record the spectra of the gas-plasma plume that occurs when laser radiation interacts with the metal surface. These spectra depend on the radiation exposure conditions and reflect the processes of atom and molecule evaporation from the molten pool. Further research will allow establishing the nature of this connection and developing optimal modes for technological processes, enabling real-time control of these processes.
Defektoskopiâ. 2023;(6):59-66
59-66
Application of the parameters of the remagnetization curve`s spectral characteristics to determine the hardness of ferromagnetic material
Abstract
The paper discusses the results of the practical application of the harmonic components obtained in the analysis of the magnetic hysteresis loop to determine the hardness of steel. The magnetic characteristics of steel, including the magnetic hysteresis loop, were determined using a DIUS-1.15M magnetic structureoscope. Using the group method of data handling by the value of odd harmonic components, a complex parameter was detected. The weighting coefficients of the influence of harmonic components on the value of the complex parameter were determined. By the example of considering the dependences of coercive force, residual induction and the complex parameter obtained by the method of group argument accounting on the Brinell hardness of the material, it is shown that the complex parameter can be used to determine the hardness with the smallest error.
Defektoskopiâ. 2023;(6):67-69
67-69
Automatic system of individual dosimetric control Coros-333
Abstract
The Russian and foreign thermoluminescent (TL) systems of individual dosimetric control used in the nuclear industry and in radiation monitoring are compared, their limitations are indicated. A new automated system for individual dosimetric control COROS-333 is described, which uses the effect of optically stimulated luminescence and surpasses TL analogs in many parameters and is designed to measure personal dose equivalent for the whole body, the lens of the eye, and skin.
Defektoskopiâ. 2023;(6):70-72
70-72