Open Access
Access granted
Subscription Access
No 2 (2025)
Articles
К ЧИТАТЕЛЯМ
Metally. 2025;(2):1-1
1-1
5-10
ANALYSIS OF CHANGES IN THE COMPOSITION AND CONTENT OF NON-METALLIC INCLUSIONS IN THE PROCESS OF DYNAMO STEEL PRODUCTION
Abstract
Metal samples taken during the melting process of experimental technology of dynamo steel production have been analyzed. Metal samples were taken at different stages of ladle processing, from the intermediate ladle, from slab and hot-rolled sheet for six industrial processes of dynamo steel melting and investigated by scanning electron microscopy and fractional gas analysis methods. Based on the results of the studies, the main mechanisms and stages determining the formation of nonmetallic inclusions in the process of production of electrical dynamo steel were established.
Metally. 2025;(2):11-23
11-23
MODELING OF THE CRYSTALLOGRAPHIC TEXTURE EVOLUTION OF ELECTRICAL STEEL DURING COLD ROLLING
Abstract
The Taylor texture evolution model is adapted for electrical steel in this paper by taking into account the different nature of hardening of different types of slip systems. The initial data for the modelling were the texture of annealed semi-finished hot-rolled plate before cold rolling and the components of the plastic strain tensor. Initial critical resolved shear stresses and the hardening laws of various slip systems were obtained from literature and from the analysis results of the work hardening inhomogeneity by the Generalized Pole Figures registered at each pass of the cold rolling. The analysis of the substructural state of the differently oriented crystallites showed the inhomogeneity of the accumulated distortion of the crystal lattice for grains belonging to different components of the rolling texture. The results of experimental studies of the crystallographic texture of samples after each pass during cold rolling are compared with the calculated values of the grain orientation distribution function.
Metally. 2025;(2):24-33
24-33
APPLICATION OF SCANNING ELECTRON MICROSCOPY AND GLOW DISCHARGE ATOMIC EMISSION SPECTROMETRY METHODS TO EVALUATE THE MORPHOLOGY OF THE NEAR-SURFACE AREA OF ROLLED ELECTRICAL STEEL SAMPLES
Abstract
The paper considers the possibility of using methods of scanning electron microscopy and atomic emission spectrometry of glow discharge for a comprehensive assessment of the microstructure and layer-by-layer distribution of elements in samples of rolled electrical steel after processing and applying an insulating coating. The expediency of using scanning electron microscopy for visual assessment of the depth distribution of elements and determination of the morphology of particles in the zone of internal oxidation is shown. The consistency of the research results obtained by scanning electron microscopy and glow discharge spectrometry has been established, which makes it possible to use glow discharge atomic emission spectrometry for rapid analysis of the amount of silicon oxide in the internal oxidation zone of samples after decarburization, as well as for quantitative assessment of coating components.
Metally. 2025;(2):34-40
34-40
THE METHOD OF INVESTIGATING TEXTURE AND DOMAIN STRUCTURE OF ELECTRICAL ANISOTROPIC STEEL BY MEANS OF ELECTRON MICROSCOPY
Abstract
The current study deals with the methodics of investigating crystallographic texture, grain structure and domain structure of high-permeability electrical anisotropic steel after secondary recrystallization and the results obtained by this methodics by EBSD measurement. The proposed methodics allows to observe the domain structure of electrical anisotropic steel without introducing mechanical stresses during sample prepearation. This work also describes the new formula for calculation of magnetic induction based on the weighted average values of Goss deviation angles and the standart deviations of these values.
Metally. 2025;(2):41-48
41-48
ABOUT CHARACTERISTIC TENSILE DEGRADATION STRESSES OF STRUCTURAL MATERIALS
Abstract
The stages of fracture of the structural steels 12Cr18Ni10T and F500W in tension are considered. The shape of the deformation diagrams has been analysed and characteristic stresses of material degradation, which characterise the stages of damage development, have been identified. On the basis of the analysis of the strain dependence of the second derivative of stress on strain on the load curve, a new characteristic point of degradation σD2 has been singled out. During the stretching of the specimens, the zones of plastic deformation were evaluated by means of digital image correlation (DIC), acoustic emission (AE) parameters and material damage characteristics. It is shown that after the stress σD2 is reached, a highly deformed plastic zone is formed, the damage increases and the acoustic emission characteristics change. The correlation between the estimated parameters and the stage of fracture development has been established.
Metally. 2025;(2):49-56
49-56
INFLUENCE OF THE CONDITIONS OF SOLID-PHASE PRESSURE WELDING AND HEAT TREATMENT ON THE STRUCTURE AND PROPERTIES OF JOINTS OF THE INTERMETALLIC ALLOY VKNA-25 Mono WITH SUPERALLOY EP975. I. INFLUENCE OF THE VACUUM DEPTH AT SOLID-STATE JOINTS
Abstract
The article is devoted to the development of a method for producing solid-state joints (SSJ) of blades with a disk in «blades and disks» type parts operating under conditions of high tensile, bending and thermal stresses (static, re-static, fatigue, etc.). The quality of SSJ depends on such factors as the atmosphere (degree of vacuum) during pressure welding (PW), preparation of the welded planes, temperature, magnitude and duration of pressure application during PW. The first part of the article is devoted to the study of the effect of the degree of vacuum in the PW process on the quality of welded joints, which was evaluated by the tensile strength of welded samples at room temperature. The study of the influence of SSJ conditions under conditions of superplasticity of only a disk alloy on the structure and properties of welded joints showed that samples with a specially prepared surface obtained under low vacuum conditions during SSJ demonstrate tensile strength, which, apparently, can be considered sufficient to ensure long-term operation of such a part as «blisk» in gas turbine engines. Carrying out PW under conditions of high vacuum made it possible to obtain a welded joint with tensile strength exceeding that of the least strong at room temperature welded high-heat-resistant alloy VKNA-25 with a single-crystal structure. Carrying out heat treatment (1200 °C / 6 h + 950 °C / 6 h) after PW, necessary for the formation of a coarse-grained structure in a disk alloy, ensuring its high heat resistance characteristics, does not affect the mechanical properties of welded joints.
Metally. 2025;(2):57-69
57-69
EFFECT OF ROLLING WITH REVERSAL ON THE PHYSICAL AND MECHANICAL PROPERTIES OF AD1 ALLOY SHEETS
Abstract
The article presents the results of a study of the effect of changing the deformation direction of AD1 aluminum alloy sheets during cold rolling on the distribution of their hardness and specific electrical conductivity. Some of the initial blanks were deformed in the longitudinal direction, and some were turned 90° before the second pass. The effect of the deformation direction on changing the grain shape in the microstructure of rolled aluminum was established. During longitudinal rolling of sheets in one direction, the grain shape is elongated, their average length is 25 μm, and their width is 15 μm. After rolling with reversal, the grain shape is close to spherical, the grain size is about 20 μm. It is shown that during longitudinal rolling after two passes with a total reduction of 25%, in the center of the sheets, the specific electrical conductivity κ = 16,7 μS/m, hardness 39 HV; at the side edges κ = 24,2 μS/m, and the hardness 27,1 HV, the difference is about 44%. When rolling sheets with reversal, a less pronounced difference in the distribution of specific electrical conductivity and hardness is noted: in the central part κ ≈ 21,8 μS/m and hardness 23,6 HV, in the corners the maximum value of S is about 23,5 μS/m, hardness 25,3 HV, the difference is about 8%. An adequate linear equation has been obtained, which establishes a relationship between the specific electrical conductivity and hardness of deformed sheets. The use of the obtained dependencies expands the scope of application of operational non-destructive testing of the physical and mechanical properties of rolled aluminum. A positive effect of sheet rotation during rolling on increasing plasticity by 20% during shaping by stamping has been established. The research results can be used in developing rolling modes for sheet blanks for stamping high-quality parts from AD1 alloy at machine-building enterprises.
Metally. 2025;(2):70-76
70-76
DETERMINATION OF THE DOSE OF MECHANICAL ENERGY REQUIRED FOR MILLING ALUMINUM ALLOY CHIPS IN A PLANETARY MILL
Abstract
The paper presents the results of modeling the motion of milling bodies in the working chamber of a planetary mill at different processing speeds. Quantitative estimates of the effect of processing speed on the kinematic characteristics of the motion of milling bodies, the number of collisions, the total energy loss during collisions and the average specific loss of collision energy are obtained. Changes in these parameters for «body-body» and «body-camera» collisions have been studied. Experimental studies have been conducted to study the effect of speed, machining time in a planetary mill and the ratio of chip mass to the mass of milling bodies on the transformation process of chip material. By comparing the calculated and experimental data, the minimum dose of mechanical energy was determined, which ensures the formation of flake-like particles and powder from the chip material.
Metally. 2025;(2):77-87
77-87
SELECTIVE EXTRACTION OF COPPER AND ALUMINUM FROM OXIDIZED COPPER ORES
Abstract
Selective extraction of copper and aluminum from oxidized copper ores has been studied. It includes the following stages: 1) autoclave leaching of the starting material with 5% solution of (NH4)2SO4; 2) separation of the soluble copper complex [Cu(NH3)4]2+ from the aluminosilicate residue; 3) mixing the moistened residue with concentrated sulfuric acid; 4) sulfatizing roasting; 5) leaching of the sulfated mass with water. During autoclave leaching, copper passes into solution in the form of a complex compound [Cu(NH3)4]2+ separating from a number of elements (Fe, Ca, Mg, Al, Si). During sulfatization, aluminosilicate minerals (feldspar, kaolin, illite and goethite) decompose and pass into the corresponding sulfate compounds. In this case, unstable sulfates, mainly iron (III) sulfate, decompose to the corresponding oxide, and aluminum remains in the form of sulfate Al2(SO4)3. As a result of leaching of the sulfated mass with water, iron and silicon oxides remain in the residue, and aluminum passes into solution. The change in the mineralogical composition of the initial and sulfated ore mass was studied using DTA/TG, X-ray diffraction, and SEM/EDS analysis.
Metally. 2025;(2):88-96
88-96