Pub Date : 2023-06-29DOI: 10.17073/0368-0797-2023-3-327-329
M. A. Porfir’ev, V. Gromov, R. Kryukov
The methods of modern physical materials science were used to analyze the evolution of microhardness, tribological properties, dislocation substructure and phase composition of the rails with increased wear resistance and contact endurance of DT 400 IR category after missed tonnage of 187 million gross tons on the experimental ring of Russian Railways. It is shown that extremely long-term operation of the rails is accompanied by a decrease (3.1 times) in wear parameter of the rolling surface and an increase (1.4 times) in microhardness, scalar dislocation density (1.5 times) and Fe3C carbide content (1.24 times). Operation of the rails led to a decrease in the crystal lattice parameter, which correlates with an increase in the content of iron carbide. We made the assumptions about physical causes of the change in parameters.
{"title":"Evolution of structural-phase state and properties of hypereutectoid steel rails at long-term operation","authors":"M. A. Porfir’ev, V. Gromov, R. Kryukov","doi":"10.17073/0368-0797-2023-3-327-329","DOIUrl":"https://doi.org/10.17073/0368-0797-2023-3-327-329","url":null,"abstract":"The methods of modern physical materials science were used to analyze the evolution of microhardness, tribological properties, dislocation substructure and phase composition of the rails with increased wear resistance and contact endurance of DT 400 IR category after missed tonnage of 187 million gross tons on the experimental ring of Russian Railways. It is shown that extremely long-term operation of the rails is accompanied by a decrease (3.1 times) in wear parameter of the rolling surface and an increase (1.4 times) in microhardness, scalar dislocation density (1.5 times) and Fe3C carbide content (1.24 times). Operation of the rails led to a decrease in the crystal lattice parameter, which correlates with an increase in the content of iron carbide. We made the assumptions about physical causes of the change in parameters.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73811980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-29DOI: 10.17073/0368-0797-2023-3-302-310
A. Burkov, M. Kulik
To improve the tribotechnical behavior and heat resistance of steel 1035, composite metalloceramic Fe–Al/HfC coatings were prepared by electrospark deposition. A non-localized anode was used as an electrode consisting of a mixture of iron and aluminum granules with a molar ratio of 3:2 and with the addition of HfC powder. The cathode gain had positive values indicating that HfC powder can be deposited on steel 1035 using the Fe60Al40 anode mixture. Moreover, the cathode gain monotonically increased with the increase in addition of HfC powder to the anode mixture. The coatings structure is represented by a matrix of FeAl intermetallic compound reinforced with HfC grains, which corresponds to the structure of a metalloceramic composite. Concentration of HfC in the coating increased with the addition of HfC powder to the anode mixture. Deposition of Fe–Al/HfC coatings according to the proposed technique allows reducing the friction coefficient of steel 1035 from 6 to 40 vol. %. Depending on the concentration of HfC in the anode mixture, the wear resistance of Fe–Al/HfC coatings varied nonmonotonically with a maximum at 8 vol. %. The use of Fe–Al/HfC coatings makes it possible to increase the wear resistance of the steel surface to 10 times. Comparison of the final weight gain of the samples after 100 h of oxidation resistance tests at a temperature of 700 °C allows us to conclude that electrospark deposition Fe–Al/HfC coatings can increase the oxidation resistance of steel 1035 by 1.7–2.2 times. Analysis of the study results shows that adhesion of Fe–Al composition to HfC is weak. This was reflected in decrease in hardness, wear resistance and oxidation resistance of coatings with an increase in the concentration of HfC in the anode mixture above 8 vol. %.
{"title":"Electrospark deposition of metalloceramic Fe–Al/HfC coating on steel 1035","authors":"A. Burkov, M. Kulik","doi":"10.17073/0368-0797-2023-3-302-310","DOIUrl":"https://doi.org/10.17073/0368-0797-2023-3-302-310","url":null,"abstract":"To improve the tribotechnical behavior and heat resistance of steel 1035, composite metalloceramic Fe–Al/HfC coatings were prepared by electrospark deposition. A non-localized anode was used as an electrode consisting of a mixture of iron and aluminum granules with a molar ratio of 3:2 and with the addition of HfC powder. The cathode gain had positive values indicating that HfC powder can be deposited on steel 1035 using the Fe60Al40 anode mixture. Moreover, the cathode gain monotonically increased with the increase in addition of HfC powder to the anode mixture. The coatings structure is represented by a matrix of FeAl intermetallic compound reinforced with HfC grains, which corresponds to the structure of a metalloceramic composite. Concentration of HfC in the coating increased with the addition of HfC powder to the anode mixture. Deposition of Fe–Al/HfC coatings according to the proposed technique allows reducing the friction coefficient of steel 1035 from 6 to 40 vol. %. Depending on the concentration of HfC in the anode mixture, the wear resistance of Fe–Al/HfC coatings varied nonmonotonically with a maximum at 8 vol. %. The use of Fe–Al/HfC coatings makes it possible to increase the wear resistance of the steel surface to 10 times. Comparison of the final weight gain of the samples after 100 h of oxidation resistance tests at a temperature of 700 °C allows us to conclude that electrospark deposition Fe–Al/HfC coatings can increase the oxidation resistance of steel 1035 by 1.7–2.2 times. Analysis of the study results shows that adhesion of Fe–Al composition to HfC is weak. This was reflected in decrease in hardness, wear resistance and oxidation resistance of coatings with an increase in the concentration of HfC in the anode mixture above 8 vol. %.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"04 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88357172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-29DOI: 10.17073/0368-0797-2023-3-320-326
S. Barannikova, Yu. V. Li
The work is devoted to the study of strain localization at macroscale level during parabolic mechanical hardening and pre-fracture under quasi-static loading of a carbon steel – stainless steel bimetal. The problem of estimating the scale of the phenomena that determine plasticity is decisive in the development of any theories of plastic deformation, in particular, dislocation theories. The main difficulty in constructing such theories is the reconciling the dislocation scales, characteristic for most deformation and mechanical hardening mechanisms, with macroscopic parameters of deformation processes. In the framework of the autowave model of localized plastic deformation, this problem can be reduced to the possibility of obtaining parameters from the results of macroscale observations of localized plastic flow development. During the experiments, it was confirmed that in a bimetal at any forming stage, a specific pattern of localization centers distribution is spontaneously generated - a pattern of localized plastic flow. The shape of such patterns is determined by the law of mechanical hardening acting in the material. It is shown that the observed localization patterns can be used as an informative feature in predicting the plasticity margin. In the process of uniaxial tension at the stage of parabolic mechanical hardening of the bimetal, the deformation mode is realized with the formation of several potential fracture centers. It was established that at the pre-fracture stage, during the time evolution of the wave pattern of deformation localization, the zone of active plastic deformation narrows, but the number of centers in it either remains the same with a decrease in the distance between them, or even increases. The result of this process is the formation of a macroscopic neck, and then fracture. At the pre-fracture stage, the collapse point indicates the place of future fracture and signals the need to stop the deformation process in order to avoid the fracture of the bimetallic material. Thus, the well-known manifestation of deformation macroscopic localization – formation of a neck – is preceded by complex phenomena of mutually coordinated motion of localized plasticity centers at the pre-fracture stage.
{"title":"Patterns of localized deformation at pre-fracture stage in carbon steel – stainless steel bimetal","authors":"S. Barannikova, Yu. V. Li","doi":"10.17073/0368-0797-2023-3-320-326","DOIUrl":"https://doi.org/10.17073/0368-0797-2023-3-320-326","url":null,"abstract":"The work is devoted to the study of strain localization at macroscale level during parabolic mechanical hardening and pre-fracture under quasi-static loading of a carbon steel – stainless steel bimetal. The problem of estimating the scale of the phenomena that determine plasticity is decisive in the development of any theories of plastic deformation, in particular, dislocation theories. The main difficulty in constructing such theories is the reconciling the dislocation scales, characteristic for most deformation and mechanical hardening mechanisms, with macroscopic parameters of deformation processes. In the framework of the autowave model of localized plastic deformation, this problem can be reduced to the possibility of obtaining parameters from the results of macroscale observations of localized plastic flow development. During the experiments, it was confirmed that in a bimetal at any forming stage, a specific pattern of localization centers distribution is spontaneously generated - a pattern of localized plastic flow. The shape of such patterns is determined by the law of mechanical hardening acting in the material. It is shown that the observed localization patterns can be used as an informative feature in predicting the plasticity margin. In the process of uniaxial tension at the stage of parabolic mechanical hardening of the bimetal, the deformation mode is realized with the formation of several potential fracture centers. It was established that at the pre-fracture stage, during the time evolution of the wave pattern of deformation localization, the zone of active plastic deformation narrows, but the number of centers in it either remains the same with a decrease in the distance between them, or even increases. The result of this process is the formation of a macroscopic neck, and then fracture. At the pre-fracture stage, the collapse point indicates the place of future fracture and signals the need to stop the deformation process in order to avoid the fracture of the bimetallic material. Thus, the well-known manifestation of deformation macroscopic localization – formation of a neck – is preceded by complex phenomena of mutually coordinated motion of localized plasticity centers at the pre-fracture stage.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85290195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-28DOI: 10.17073/0368-0797-2023-3-272-282
S. Zaides, Ho Minh Quan
The article discusses influence of the main technological parameters of pendulum surface plastic deformation (SPD) on the mechanical properties of surface layer of cylindrical parts made of carbon steel. Using the hardness tester HBRV-187.5 and the microhardness tester HMV-G21, we determined hardness of the surface layer, microhardness and depth of the work-hardened layer of hardened parts. In addition, the results of calculating the hardening degree are presented, which is important information for evaluating the effectiveness of SPD method in terms of improving the metal mechanical properties. Experimental studies showed that after pendulum SPD (at different processing modes), hardness of the surface layer increases by 9 – 12 % compared to hardness of the original surface, and the microhardness increases by 1.5 – 1.7 times, which leads to a significant hardening of the cylindrical billet surface layer. Depth of the hardened layer varies in the range of 0.9 – 1.1 mm, while the hardening degree is 45 – 65 %. Using the software package Statistica 10.1, which allows solving optimization problems based on statistical analysis and building an optimization model, we determined the optimal modes of hardening by pendulum SPD. These modes simultaneously provide both the maximum depth of the hardened layer and the highest hardening degree of the surface layer. They are formed under the following processing modes: radial interference t = 0.15 – 0.2 mm; longitudinal feed s = 0.07 – 0.11 mm/rev; billet rotation frequency nb = 160 – 200 min−1; frequency of the working tool pendulum movement nt = 110 – 130 strokes/min; angular amplitude of the working tool α = 35 – 40°. According to the results of experimental data and numerical calculations, it was established that the average grain size in pendulum SPD decreases by 30 – 40 % compared to the initial size, and the dislocation density increases by 2.5 times.
{"title":"Degree and depth of hardening under pendulum surface plastic deformation of carbon steel","authors":"S. Zaides, Ho Minh Quan","doi":"10.17073/0368-0797-2023-3-272-282","DOIUrl":"https://doi.org/10.17073/0368-0797-2023-3-272-282","url":null,"abstract":"The article discusses influence of the main technological parameters of pendulum surface plastic deformation (SPD) on the mechanical properties of surface layer of cylindrical parts made of carbon steel. Using the hardness tester HBRV-187.5 and the microhardness tester HMV-G21, we determined hardness of the surface layer, microhardness and depth of the work-hardened layer of hardened parts. In addition, the results of calculating the hardening degree are presented, which is important information for evaluating the effectiveness of SPD method in terms of improving the metal mechanical properties. Experimental studies showed that after pendulum SPD (at different processing modes), hardness of the surface layer increases by 9 – 12 % compared to hardness of the original surface, and the microhardness increases by 1.5 – 1.7 times, which leads to a significant hardening of the cylindrical billet surface layer. Depth of the hardened layer varies in the range of 0.9 – 1.1 mm, while the hardening degree is 45 – 65 %. Using the software package Statistica 10.1, which allows solving optimization problems based on statistical analysis and building an optimization model, we determined the optimal modes of hardening by pendulum SPD. These modes simultaneously provide both the maximum depth of the hardened layer and the highest hardening degree of the surface layer. They are formed under the following processing modes: radial interference t = 0.15 – 0.2 mm; longitudinal feed s = 0.07 – 0.11 mm/rev; billet rotation frequency nb = 160 – 200 min−1; frequency of the working tool pendulum movement nt = 110 – 130 strokes/min; angular amplitude of the working tool α = 35 – 40°. According to the results of experimental data and numerical calculations, it was established that the average grain size in pendulum SPD decreases by 30 – 40 % compared to the initial size, and the dislocation density increases by 2.5 times.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"50 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83379945","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-28DOI: 10.17073/0368-0797-2023-3-294-301
M. Anosov, D. Shatagin, M. A. Chernigin, Yu.S. Mordovina, E. S. Anosova
The use of metallic products 3D-printing is a modern, promising technology that improves production efficiency. However, using this technology is associated with a number of problems, for example, with increased microstructural heterogeneity and defects in metal. Therefore, it is necessary to carry out researches to identify 3D-printing modes ensuring the most homogeneous, stable and non-defect structure. In this work, a study was made of the process of structure formation of 30KhGSA steel in the process of Wire and Arc Additive Manufacturing (WAAM) under various printing modes. Microstructural analysis, microhardness measurement and fractal analysis were used for assessment of the obtained billets. In all surfacing modes, a significant structural inhomogeneity of the deposited billet was revealed, which is explained by the thermal effect of the deposited layer on the already crystallized metal. Nevertheless, we found the mode that gives the most favorable microstructure in terms of its uniformity and equiaxed grains. With an increase in WAAM heat input values, an increase in the productivity of the process is observed and a decrease in the number of pores in the material is recorded. However, when the heat input of the surfacing process exceeds 1000 J/mm, the structural inhomogeneity of the material increases and its microhardness significantly decreases. Based on the studies, as a WAAM 3D-printing mode for Np-30KhGSA alloy, a mode with a heat input of about 920 J/mm can be chosen, which provides the lowest structural inhomogeneity and a sufficiently high productivity of the growth process with the absence of defects in the form of pores and elements of not melted wire.
{"title":"Structure formation of Np-30KhGSA alloy in wire and arc additive manufacturing","authors":"M. Anosov, D. Shatagin, M. A. Chernigin, Yu.S. Mordovina, E. S. Anosova","doi":"10.17073/0368-0797-2023-3-294-301","DOIUrl":"https://doi.org/10.17073/0368-0797-2023-3-294-301","url":null,"abstract":"The use of metallic products 3D-printing is a modern, promising technology that improves production efficiency. However, using this technology is associated with a number of problems, for example, with increased microstructural heterogeneity and defects in metal. Therefore, it is necessary to carry out researches to identify 3D-printing modes ensuring the most homogeneous, stable and non-defect structure. In this work, a study was made of the process of structure formation of 30KhGSA steel in the process of Wire and Arc Additive Manufacturing (WAAM) under various printing modes. Microstructural analysis, microhardness measurement and fractal analysis were used for assessment of the obtained billets. In all surfacing modes, a significant structural inhomogeneity of the deposited billet was revealed, which is explained by the thermal effect of the deposited layer on the already crystallized metal. Nevertheless, we found the mode that gives the most favorable microstructure in terms of its uniformity and equiaxed grains. With an increase in WAAM heat input values, an increase in the productivity of the process is observed and a decrease in the number of pores in the material is recorded. However, when the heat input of the surfacing process exceeds 1000 J/mm, the structural inhomogeneity of the material increases and its microhardness significantly decreases. Based on the studies, as a WAAM 3D-printing mode for Np-30KhGSA alloy, a mode with a heat input of about 920 J/mm can be chosen, which provides the lowest structural inhomogeneity and a sufficiently high productivity of the growth process with the absence of defects in the form of pores and elements of not melted wire.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76861123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-28DOI: 10.17073/0368-0797-2023-3-290-293
A. R. Fastуkovskii, M. I. Glukhov, V. A. Vakhrolomeev
Metallurgical production is a highly energy-intensive process, and the search for solutions to reduce energy costs remains an urgent task for all stages. In this regard, the production of finished rolled products is considered as the most promising direction for the implementation of energy-saving technologies. There are two ways to reduce energy costs in hot rolling of section bars: saving energy for heating and improving the use of the main equipment to reduce intermediate energy costs. Due to the difference in silt conditions at the moment of capture and at the steady stage of the rolling process, a reserve of retracting friction forces arises, which can be used for additional shaping in non-drive devices and thereby increase the efficiency of the main equipment and reduce overall energy costs. For the practical implementation of the proposed concept, dependence was obtained that makes it possible to estimate the power potential that is not used at the steady stage of the rolling process. Using the obtained dependence, it was found that when rolling in smooth rolls, the potential of friction forces is used only by 50 – 60 %, and when rolling in calibers, by 35 – 40 %. It was experimentally established that during the rolling of shaped sections in passes with an elongation ratio of less than 1.10 – 1.15, more than 50 % of the energy is spent on idling. However, by replacing drive stands in these passes with non-drive cassettes (in continuous groups), it is possible to increase the efficiency of adjacent stands by 4 – 5 % and reduce energy costs.
{"title":"Reserves for reducing energy consumption when rolling section bars on modern rolling mills","authors":"A. R. Fastуkovskii, M. I. Glukhov, V. A. Vakhrolomeev","doi":"10.17073/0368-0797-2023-3-290-293","DOIUrl":"https://doi.org/10.17073/0368-0797-2023-3-290-293","url":null,"abstract":"Metallurgical production is a highly energy-intensive process, and the search for solutions to reduce energy costs remains an urgent task for all stages. In this regard, the production of finished rolled products is considered as the most promising direction for the implementation of energy-saving technologies. There are two ways to reduce energy costs in hot rolling of section bars: saving energy for heating and improving the use of the main equipment to reduce intermediate energy costs. Due to the difference in silt conditions at the moment of capture and at the steady stage of the rolling process, a reserve of retracting friction forces arises, which can be used for additional shaping in non-drive devices and thereby increase the efficiency of the main equipment and reduce overall energy costs. For the practical implementation of the proposed concept, dependence was obtained that makes it possible to estimate the power potential that is not used at the steady stage of the rolling process. Using the obtained dependence, it was found that when rolling in smooth rolls, the potential of friction forces is used only by 50 – 60 %, and when rolling in calibers, by 35 – 40 %. It was experimentally established that during the rolling of shaped sections in passes with an elongation ratio of less than 1.10 – 1.15, more than 50 % of the energy is spent on idling. However, by replacing drive stands in these passes with non-drive cassettes (in continuous groups), it is possible to increase the efficiency of adjacent stands by 4 – 5 % and reduce energy costs.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73935093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-28DOI: 10.17073/0368-0797-2023-3-283-289
D. Shalaevskii
Thermal mode of the working roll barrel in a hot-rolling mill is a significant technological factor that affects the steel strip quality, its cross section, and durability of working rolls. A reliable calculation of the temperature mode parameters makes it possible to determine the thermal profile shape and the best profiling of the roll barrel surface, as well as to reduce defects in steel strip flatness. The most common is the balance model of roll thermal mode. Its accuracy is largely determined by thermophysical constants, in particular, the heat transfer coefficients of the rolls: contact – with the strip and convective – with cooling water. There are various data on the values and methods for calculating these coefficients, but most of them do not take into account the presence of pauses in rolling rhythm of the finishing group of stands, the duration of which is significant. Failure to take this factor into account entails significant errors in calculations of the thermal mode. A passive experiment was carried out, during which surface temperatures of the working rolls’ barrels were measured using a thermocouple at several points along their length immediately after they fell out. Also, the parameters of steel strip rolling before roll change were determined: rolling rhythm coefficients, strip reduction in stands, water consumption for cooling rolls and some others. As a result, an empirical equation was obtained for calculating the contact heat transfer coefficient, taking into account the main technological factors. The use of refined coefficients for calculating the temperatures of the roll barrel significantly increased the accuracy of predicting the thermal mode, in particular, the thermal profile of the working roll, based on values of the rolling parameters.
{"title":"Investigation of thermal mode of hot-rolling mill working rolls in order to improve the accuracy of calculating the thermal profile of their barrels’ surface","authors":"D. Shalaevskii","doi":"10.17073/0368-0797-2023-3-283-289","DOIUrl":"https://doi.org/10.17073/0368-0797-2023-3-283-289","url":null,"abstract":"Thermal mode of the working roll barrel in a hot-rolling mill is a significant technological factor that affects the steel strip quality, its cross section, and durability of working rolls. A reliable calculation of the temperature mode parameters makes it possible to determine the thermal profile shape and the best profiling of the roll barrel surface, as well as to reduce defects in steel strip flatness. The most common is the balance model of roll thermal mode. Its accuracy is largely determined by thermophysical constants, in particular, the heat transfer coefficients of the rolls: contact – with the strip and convective – with cooling water. There are various data on the values and methods for calculating these coefficients, but most of them do not take into account the presence of pauses in rolling rhythm of the finishing group of stands, the duration of which is significant. Failure to take this factor into account entails significant errors in calculations of the thermal mode. A passive experiment was carried out, during which surface temperatures of the working rolls’ barrels were measured using a thermocouple at several points along their length immediately after they fell out. Also, the parameters of steel strip rolling before roll change were determined: rolling rhythm coefficients, strip reduction in stands, water consumption for cooling rolls and some others. As a result, an empirical equation was obtained for calculating the contact heat transfer coefficient, taking into account the main technological factors. The use of refined coefficients for calculating the temperatures of the roll barrel significantly increased the accuracy of predicting the thermal mode, in particular, the thermal profile of the working roll, based on values of the rolling parameters.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"219 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72673869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-06DOI: 10.17073/0368-0797-2023-2-191-196
Y. Ivanov, N. Prokopenko, E. Petrikova, V. Shugurov, A. Teresov
High-entropy alloys (HEA) are multi-element materials and contain at least five elements of similar concentration. HEA are, as a rule, single- phase thermodynamically stable substitutional solid solutions, mainly based on a body-centered cubic and face-centered cubic crystal lattice. Solid solution stabilization during the crystallization of a high-entropy alloy is provided by the interaction of a number of factors, namely, a high mixing entropy and low diffusion rate of components, and a low growth rate of crystallites from the melt. The purpose of this work was to obtain new knowledge about the structure and properties of high-entropy films synthesized on a metal substrate during deposition of a multi-element metal plasma in argon atmosphere. The plasma was formed as a result of independent plasma-assisted electric arc cathodes of the following metals: Ti, Al, Cu, Nb, Zr sputtering. As a result of the performed studies, the deposition mode was revealed, which allows the formation of films of various thicknesses of close to equiatomic composition. Transmission electron microscopy methods have established that the films are multilayer formations and have nanoscale amorphous-crystalline structure. Microhardness of the films significantly depends on the ratio of number of the forming elements and varies from 12 to 14 GPa, Young’s modulus – from 230 to 310 GPa. Crystallization of the films was carried out by irradiation with a pulsed electron beam. As a result of processing, a two-phase state is formed. The main phase is α-NbZrTiAl with a volume-centered cubic crystal lattice with a parameter of 0.32344 nm; the second phase of CuZr composition has a simple cubic lattice.
{"title":"Multilayer amorphous-crystalline high-entropy metal films","authors":"Y. Ivanov, N. Prokopenko, E. Petrikova, V. Shugurov, A. Teresov","doi":"10.17073/0368-0797-2023-2-191-196","DOIUrl":"https://doi.org/10.17073/0368-0797-2023-2-191-196","url":null,"abstract":"High-entropy alloys (HEA) are multi-element materials and contain at least five elements of similar concentration. HEA are, as a rule, single- phase thermodynamically stable substitutional solid solutions, mainly based on a body-centered cubic and face-centered cubic crystal lattice. Solid solution stabilization during the crystallization of a high-entropy alloy is provided by the interaction of a number of factors, namely, a high mixing entropy and low diffusion rate of components, and a low growth rate of crystallites from the melt. The purpose of this work was to obtain new knowledge about the structure and properties of high-entropy films synthesized on a metal substrate during deposition of a multi-element metal plasma in argon atmosphere. The plasma was formed as a result of independent plasma-assisted electric arc cathodes of the following metals: Ti, Al, Cu, Nb, Zr sputtering. As a result of the performed studies, the deposition mode was revealed, which allows the formation of films of various thicknesses of close to equiatomic composition. Transmission electron microscopy methods have established that the films are multilayer formations and have nanoscale amorphous-crystalline structure. Microhardness of the films significantly depends on the ratio of number of the forming elements and varies from 12 to 14 GPa, Young’s modulus – from 230 to 310 GPa. Crystallization of the films was carried out by irradiation with a pulsed electron beam. As a result of processing, a two-phase state is formed. The main phase is α-NbZrTiAl with a volume-centered cubic crystal lattice with a parameter of 0.32344 nm; the second phase of CuZr composition has a simple cubic lattice.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"52 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83969112","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-06DOI: 10.17073/0368-0797-2023-2-162-167
S. Barannikova, M. V. Nadezhkin, P. V. Iskhakova
The paper is devoted to correlation dependences of ultrasound velocity with characteristics of strength and plasticity in uniaxial tension of Fe18Cr10Ni austenitic stainless steel with a unique set of physical and mechanical properties. Such a successful set of mechanical properties is provided by dislocation slip and twinning, the formation of stacking faults, and martensitic transformation. It should be noted that the assessment of changes in the mechanical characteristics of metals (especially at low temperatures) is a very laborious task and requires the use of non-destructive control methods. Experimental data was obtained using a bench designed to synchronize with recording of the “stress – strain” diagram for determining the values of ultrasound velocity propagation and the attenuation coefficient of the ultrasonic wave as a function of deformation. Measurement of ultrasound velocity propagation was reduced to determining the time of passage of an ultrasonic Rayleigh pulse between transmitting and receiving transducers. Attenuation was determined from the change in pulse shape. The pulses were excited by a piezoelectric transducer at a frequency of 5 MHz. The authors experimentally studied static loading effect on acoustic characteristics and calculated the destruction parameters. The propagation ultrasound velocity in deformable material is an informative feature for analyzing the nature of the processes that control plasticity. The effect of test temperature in the range 180 K ≤ T ≤ 320 K on acoustic and mechanical characteristics of the steel was studied to ensure control of its structural state and mechanical properties by means of non-destructive testing. The temperature range was chosen taking into account the possibility of direct γ → α′ martensitic transformation.
{"title":"Mechanical and acoustic properties of deformable alloys","authors":"S. Barannikova, M. V. Nadezhkin, P. V. Iskhakova","doi":"10.17073/0368-0797-2023-2-162-167","DOIUrl":"https://doi.org/10.17073/0368-0797-2023-2-162-167","url":null,"abstract":"The paper is devoted to correlation dependences of ultrasound velocity with characteristics of strength and plasticity in uniaxial tension of Fe18Cr10Ni austenitic stainless steel with a unique set of physical and mechanical properties. Such a successful set of mechanical properties is provided by dislocation slip and twinning, the formation of stacking faults, and martensitic transformation. It should be noted that the assessment of changes in the mechanical characteristics of metals (especially at low temperatures) is a very laborious task and requires the use of non-destructive control methods. Experimental data was obtained using a bench designed to synchronize with recording of the “stress – strain” diagram for determining the values of ultrasound velocity propagation and the attenuation coefficient of the ultrasonic wave as a function of deformation. Measurement of ultrasound velocity propagation was reduced to determining the time of passage of an ultrasonic Rayleigh pulse between transmitting and receiving transducers. Attenuation was determined from the change in pulse shape. The pulses were excited by a piezoelectric transducer at a frequency of 5 MHz. The authors experimentally studied static loading effect on acoustic characteristics and calculated the destruction parameters. The propagation ultrasound velocity in deformable material is an informative feature for analyzing the nature of the processes that control plasticity. The effect of test temperature in the range 180 K ≤ T ≤ 320 K on acoustic and mechanical characteristics of the steel was studied to ensure control of its structural state and mechanical properties by means of non-destructive testing. The temperature range was chosen taking into account the possibility of direct γ → α′ martensitic transformation.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90559049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-06DOI: 10.17073/0368-0797-2023-2-236-243
M. Lyakhovets, G. V. Makarov, A. S. Salamatin
The article deals with the formation of model implementations of time series of data (based on in-situ data) of controlled and uncontrolled impacts in simulator-training and digital modeling systems. Such simulators are becoming increasingly widespread due to the development of information and computer technologies, automated research systems, training systems, digital modeling technologies (APM modeling), as well as digital counterparts and advanced control systems. The formed implementations of impacts can characterize situations of normal process flow, emergency and pre-emergency states, or specific representative situations for training operators and technological personnel, software testing, research and tuning of algorithms and search for optimal control actions. Using examples from the metallurgical industry, the possibility of forming several interrelated impacts based on models of nonlinear dynamics and multivariate dynamic databases is shown. The Lorentz system describing the thermal convection of a fluid medium is considered as a model of the impacts formation. The model parameters for the low- and high-frequency components are determined separately, by processing in-situ data. Next, a training sample is formed using normalization and relay-exponential smoothing operations. The implementations of the actions are formed taking into account the mutual correlation of data based on models of chemical dynamics and are adjusted to the specified properties on a limited sample of a given volume with the required accuracy using a generator in the form of a closed dynamic system. The generator in form of a closed dynamic system is built on the basis of a multidimensional generating autoregressive model with adjustable coefficients. An example of the formation of data series on technological parameters of a blast furnace (the degree of wear of the furnace lining, temperature sensor readings and heat flux density) is shown.
{"title":"Data generation for digital simulators of metallurgical process operators","authors":"M. Lyakhovets, G. V. Makarov, A. S. Salamatin","doi":"10.17073/0368-0797-2023-2-236-243","DOIUrl":"https://doi.org/10.17073/0368-0797-2023-2-236-243","url":null,"abstract":"The article deals with the formation of model implementations of time series of data (based on in-situ data) of controlled and uncontrolled impacts in simulator-training and digital modeling systems. Such simulators are becoming increasingly widespread due to the development of information and computer technologies, automated research systems, training systems, digital modeling technologies (APM modeling), as well as digital counterparts and advanced control systems. The formed implementations of impacts can characterize situations of normal process flow, emergency and pre-emergency states, or specific representative situations for training operators and technological personnel, software testing, research and tuning of algorithms and search for optimal control actions. Using examples from the metallurgical industry, the possibility of forming several interrelated impacts based on models of nonlinear dynamics and multivariate dynamic databases is shown. The Lorentz system describing the thermal convection of a fluid medium is considered as a model of the impacts formation. The model parameters for the low- and high-frequency components are determined separately, by processing in-situ data. Next, a training sample is formed using normalization and relay-exponential smoothing operations. The implementations of the actions are formed taking into account the mutual correlation of data based on models of chemical dynamics and are adjusted to the specified properties on a limited sample of a given volume with the required accuracy using a generator in the form of a closed dynamic system. The generator in form of a closed dynamic system is built on the basis of a multidimensional generating autoregressive model with adjustable coefficients. An example of the formation of data series on technological parameters of a blast furnace (the degree of wear of the furnace lining, temperature sensor readings and heat flux density) is shown.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87788556","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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