Pub Date : 2023-12-29DOI: 10.17073/0368-0797-2023-6-681-687
I. Zorya, G. Poletaev, R. Rakitin
The molecular dynamics method was used to study the influence of pores of different diameters, as well as the corresponding concentration of individual vacancies, on the theoretical strength of austenite at different temperatures. The deformation in the model was carried out by shear at a constant rate of 20 m/s. We considered a shear along two directions: [ (bar 1 bar 1) 2] and [111]. The computational austenite cell had the shape of a rectangular parallelepiped 14.0 nm long, 14.0 nm high, and 5.1 nm wide. To describe interatomic interactions, the Lau EAM potential was used, which reproduces well the structural, energy, and elastic characteristics of austenite. The stress-strain curves obtained for both considered shear directions had a similar form. In the absence of dislocation sources, plastic deformation was carried out by the formation of dislocation dipoles (dislocations with opposite Burgers vectors). The presence of a pore significantly reduced the yield strength of austenite. In this case, it was found that single vacancies randomly scattered over the volume of the computational cell also lead to a decrease in the yield strength, but, of course, not as much as the pore. The emission of dislocations during deformation occurred by the formation of dislocation loops, as a rule, in two slip planes at once. The effect of pores and vacancies on the yield strength was stronger at low temperatures. As the temperature increased, the effect of defects on the critical stress at which dislocations were formed decreased. With an increase in the pore size, as well as the concentration of vacancies, the yield strength decreased. In this case, the strongest dependence was observed for pores up to 1 nm in diameter. The influence of the concentration of vacancies in the considered range on the yield strength turned out to be comparatively smoother and almost linear.
采用分子动力学方法研究了不同直径的孔隙以及相应的单个空位浓度对不同温度下奥氏体理论强度的影响。模型中的变形是通过 20 米/秒的恒定剪切速率进行的。我们考虑了沿两个方向的剪切：[2] 和 [111]。计算奥氏体晶胞的形状为长 14.0 nm、高 14.0 nm、宽 5.1 nm 的矩形平行长方体。为了描述原子间的相互作用，使用了 Lau EAM 势，它很好地再现了奥氏体的结构、能量和弹性特征。在考虑的两个剪切方向上获得的应力-应变曲线具有相似的形式。在没有位错源的情况下，塑性变形是通过形成位错偶极子（具有相反布尔格斯矢量的位错）来实现的。孔隙的存在大大降低了奥氏体的屈服强度。在这种情况下，研究发现，随机散布在计算单元体积中的单个空位也会导致屈服强度降低，但降低程度当然不如孔隙。变形过程中位错的释放通常是通过在两个滑移面上同时形成位错环来实现的。在低温条件下，孔隙和空位对屈服强度的影响更大。随着温度的升高，缺陷对形成位错的临界应力的影响减小。随着孔隙大小和空位浓度的增加，屈服强度也随之降低。在这种情况下，直径为 1 纳米以下的孔隙的依赖性最强。在所考虑的范围内，空位浓度对屈服强度的影响相对更平滑，几乎呈线性关系。
{"title":"Theoretical strength of austenite in the presence of a pore or vacancies in the crystal: Molecular dynamics study","authors":"I. Zorya, G. Poletaev, R. Rakitin","doi":"10.17073/0368-0797-2023-6-681-687","DOIUrl":"https://doi.org/10.17073/0368-0797-2023-6-681-687","url":null,"abstract":"The molecular dynamics method was used to study the influence of pores of different diameters, as well as the corresponding concentration of individual vacancies, on the theoretical strength of austenite at different temperatures. The deformation in the model was carried out by shear at a constant rate of 20 m/s. We considered a shear along two directions: [ (bar 1 bar 1) 2] and [111]. The computational austenite cell had the shape of a rectangular parallelepiped 14.0 nm long, 14.0 nm high, and 5.1 nm wide. To describe interatomic interactions, the Lau EAM potential was used, which reproduces well the structural, energy, and elastic characteristics of austenite. The stress-strain curves obtained for both considered shear directions had a similar form. In the absence of dislocation sources, plastic deformation was carried out by the formation of dislocation dipoles (dislocations with opposite Burgers vectors). The presence of a pore significantly reduced the yield strength of austenite. In this case, it was found that single vacancies randomly scattered over the volume of the computational cell also lead to a decrease in the yield strength, but, of course, not as much as the pore. The emission of dislocations during deformation occurred by the formation of dislocation loops, as a rule, in two slip planes at once. The effect of pores and vacancies on the yield strength was stronger at low temperatures. As the temperature increased, the effect of defects on the critical stress at which dislocations were formed decreased. With an increase in the pore size, as well as the concentration of vacancies, the yield strength decreased. In this case, the strongest dependence was observed for pores up to 1 nm in diameter. The influence of the concentration of vacancies in the considered range on the yield strength turned out to be comparatively smoother and almost linear.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":" 29","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139143326","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 : 2023-12-29DOI: 10.17073/0368-0797-2023-6-743-749
A. A. Babenko, R. R. Shartdinov, A. G. Upolovnikova, A. N. Smetannikov, D. A. Lobanov, A. V. Dolmatov
Influence of basicity on viscosity, crystallization onset temperature, phase composition, and structure of slags of the СаО – SiO2 – 18 % Cr2O3 – 6 % B2O3 – 3 % Аl2O3 – 8 % МgO system in the basicity range (B = CaO/SiO2 ) from 1.0 up to 2.5 was studied using vibrational viscometry, thermodynamic modeling, and Raman spectroscopy. It was established that the physical properties of slags depend on the balance of polymerization degree and phase composition. Acid slags with a basicity of 1.0 belong to the category of “long” slags and are characterized by an increased proportion of high-temperature phases up to 34.1 %. However, despite the fact that the proportion of high-temperature phases is 1.6 times higher compared to the proportion of low-temperature ones, they are characterized by a simpler silicate structure, providing a viscosity of no more than 0.25 Pa·s at a crystallization onset temperature of 1530 °C. An increase in basicity of slags of the studied oxide system (up to 2.5), along with an increase in the proportion of high-temperature phases (by almost 5.9 times), is accompanied by formation of a more complex silicate structure. The resulting four-coordination structural elements [CrO4] and [AlO4] are embedded in the silicate structure and complicate it, which increases the polymerization degree. Thus, at basicity of 2.5, due to a high proportion of high-temperature phases in the slag and development of polymerization process, slag crystallization onset temperature increases to 1700 °C and its viscosity reaches 1.0 Pa·s at a temperature of 1670 °C.
{"title":"Influence of basicity on physical properties of slags of the СаО – SiO2 – 18 % Cr2O3 – 6 % B2O3 – 3 % Аl2O3 – 8 % МgO system","authors":"A. A. Babenko, R. R. Shartdinov, A. G. Upolovnikova, A. N. Smetannikov, D. A. Lobanov, A. V. Dolmatov","doi":"10.17073/0368-0797-2023-6-743-749","DOIUrl":"https://doi.org/10.17073/0368-0797-2023-6-743-749","url":null,"abstract":"Influence of basicity on viscosity, crystallization onset temperature, phase composition, and structure of slags of the СаО – SiO2 – 18 % Cr2O3 – 6 % B2O3 – 3 % Аl2O3 – 8 % МgO system in the basicity range (B = CaO/SiO2 ) from 1.0 up to 2.5 was studied using vibrational viscometry, thermodynamic modeling, and Raman spectroscopy. It was established that the physical properties of slags depend on the balance of polymerization degree and phase composition. Acid slags with a basicity of 1.0 belong to the category of “long” slags and are characterized by an increased proportion of high-temperature phases up to 34.1 %. However, despite the fact that the proportion of high-temperature phases is 1.6 times higher compared to the proportion of low-temperature ones, they are characterized by a simpler silicate structure, providing a viscosity of no more than 0.25 Pa·s at a crystallization onset temperature of 1530 °C. An increase in basicity of slags of the studied oxide system (up to 2.5), along with an increase in the proportion of high-temperature phases (by almost 5.9 times), is accompanied by formation of a more complex silicate structure. The resulting four-coordination structural elements [CrO4] and [AlO4] are embedded in the silicate structure and complicate it, which increases the polymerization degree. Thus, at basicity of 2.5, due to a high proportion of high-temperature phases in the slag and development of polymerization process, slag crystallization onset temperature increases to 1700 °C and its viscosity reaches 1.0 Pa·s at a temperature of 1670 °C.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"20 S4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139145358","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 : 2023-07-04DOI: 10.17073/0368-0797-2023-3-376-386
D. V. Troitskii, Yu. V. Gamin, S. P. Galkin, A. Budnikov
The article discusses the main structural features of radial-shear rolling mini-mills and their most common sizes. A generalized algorithm for designing such mills using modern CAD systems is described. The main approaches to the methodology of software adaptive design of models in engineering are listed with their features and differences. In particular, the methodology of horizontal modeling, explicit modeling methodology, and resilient modeling strategy are considered. The article describes the method of virtual squeezes and presents the main geometric scheme of the spatial position of the rollers of the longitudinal profile. The data obtained as a result of the calculations were encoded and summarized in tables. The formulas presented were used in the parametric design of the roller unit of the three-roller mill 30-70 using Autodesk Inventor software. The obtained parametric model, using classical formulas of the virtual squeezes method, allows for automatic reconstruction of the deformation zone for new initial parameters. The developed model is applicable for three-roller mills with working roll angles δ = 5 – 15° and feed angles β = 18 – 22°. The article presents sketches and diagrams of the constructed model for different rolling angles – 5, 10, and 15°. As the rolling angle increases, a noticeable increase in the conicity of the roller is observed. The vector of future research on improving the obtained software model was indicated. Further research on improving the parametric model will include expanding the set of existing parameters to include the frame and full set of roller connections – neck, cover, pressing device, etc.
{"title":"Parametric model of a three-roll unit of radial-shear rolling mini-mill","authors":"D. V. Troitskii, Yu. V. Gamin, S. P. Galkin, A. Budnikov","doi":"10.17073/0368-0797-2023-3-376-386","DOIUrl":"https://doi.org/10.17073/0368-0797-2023-3-376-386","url":null,"abstract":"The article discusses the main structural features of radial-shear rolling mini-mills and their most common sizes. A generalized algorithm for designing such mills using modern CAD systems is described. The main approaches to the methodology of software adaptive design of models in engineering are listed with their features and differences. In particular, the methodology of horizontal modeling, explicit modeling methodology, and resilient modeling strategy are considered. The article describes the method of virtual squeezes and presents the main geometric scheme of the spatial position of the rollers of the longitudinal profile. The data obtained as a result of the calculations were encoded and summarized in tables. The formulas presented were used in the parametric design of the roller unit of the three-roller mill 30-70 using Autodesk Inventor software. The obtained parametric model, using classical formulas of the virtual squeezes method, allows for automatic reconstruction of the deformation zone for new initial parameters. The developed model is applicable for three-roller mills with working roll angles δ = 5 – 15° and feed angles β = 18 – 22°. The article presents sketches and diagrams of the constructed model for different rolling angles – 5, 10, and 15°. As the rolling angle increases, a noticeable increase in the conicity of the roller is observed. The vector of future research on improving the obtained software model was indicated. Further research on improving the parametric model will include expanding the set of existing parameters to include the frame and full set of roller connections – neck, cover, pressing device, etc.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"60 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79693781","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 : 2023-06-30DOI: 10.17073/0368-0797-2023-3-356-366
S. Nikulin, S. Rogachev, V. A. Belov, N. V. Shplis, A. Komissarov, V. Turilina, Y. Nikolaev
The Russian new nuclear reactors are provided with a special core catcher vessel device (cc-vessel) designed to minimize the consequences of a severe beyond design basis accident at a nuclear power plant, when the reactor pressure vessel collapses and the core melts. For manufacture of the cc-vessel structural elements, low-carbon unalloyed or low-alloyed steels are used. When a severe beyond design basis accident develops, the cc-vessel’s body is subjected to extreme temperature and force loads, which can lead to degradation of the structure, loss of strength and failure of the entire cc-vessel. To calculate the strength characteristics of the cc-vessel, which ensure its safe and reliable operation, the detailed data are required on the structure and mechanical properties of low-carbon steels at high temperatures and after extreme thermal actions simulating the development of a severe beyond design basis accident. The paper analyzes data on the structure and mechanical properties (tensile strength, crack resistance, toughness and cyclic strength) of a number of low-carbon steels under extreme temperature and force actions, including conditions simulating the development of a severe beyond design basis accident at a nuclear power plant, in order to select the material for the design of cc-vessel of nuclear reactor. New data on the structure, mechanical properties, and thermal diffusivity in a wide temperature range of a Cr – Mo steel (Russian Standard – 15KhM) as a candidate structural material for the manufacture of the cc-vessel body are presented. The low content of manganese and alloying with molybdenum and vanadium in 15KhM steel provides a finer grained structure and eliminates the steel’s tendency to temper brittleness.
{"title":"Structure and properties of steels for manufacture of core catcher vessel of nuclear reactor","authors":"S. Nikulin, S. Rogachev, V. A. Belov, N. V. Shplis, A. Komissarov, V. Turilina, Y. Nikolaev","doi":"10.17073/0368-0797-2023-3-356-366","DOIUrl":"https://doi.org/10.17073/0368-0797-2023-3-356-366","url":null,"abstract":"The Russian new nuclear reactors are provided with a special core catcher vessel device (cc-vessel) designed to minimize the consequences of a severe beyond design basis accident at a nuclear power plant, when the reactor pressure vessel collapses and the core melts. For manufacture of the cc-vessel structural elements, low-carbon unalloyed or low-alloyed steels are used. When a severe beyond design basis accident develops, the cc-vessel’s body is subjected to extreme temperature and force loads, which can lead to degradation of the structure, loss of strength and failure of the entire cc-vessel. To calculate the strength characteristics of the cc-vessel, which ensure its safe and reliable operation, the detailed data are required on the structure and mechanical properties of low-carbon steels at high temperatures and after extreme thermal actions simulating the development of a severe beyond design basis accident. The paper analyzes data on the structure and mechanical properties (tensile strength, crack resistance, toughness and cyclic strength) of a number of low-carbon steels under extreme temperature and force actions, including conditions simulating the development of a severe beyond design basis accident at a nuclear power plant, in order to select the material for the design of cc-vessel of nuclear reactor. New data on the structure, mechanical properties, and thermal diffusivity in a wide temperature range of a Cr – Mo steel (Russian Standard – 15KhM) as a candidate structural material for the manufacture of the cc-vessel body are presented. The low content of manganese and alloying with molybdenum and vanadium in 15KhM steel provides a finer grained structure and eliminates the steel’s tendency to temper brittleness.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90153213","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 : 2023-06-30DOI: 10.17073/0368-0797-2023-3-344-355
N. V. Podusovskaya, O. Komolova, K. Grigorovich, A. Pavlov, V. Aksenova, B. Rumyantsev, M. Zheleznyi
The elemental and phase compositions of electric arc furnace (EAF) dust from PJSC Severstal were studied. We carried out the thermodynamic modeling of zinc and lead selective extraction process and determined its possible mechanisms. EAF dust was heated in the temperature range of 20 – 1300 °C in vacuum resistance furnace and the Tamman furnace with flowing argon. Experiments in the vacuum resistance furnace with linear heating showed that lead and zinc removal from the sample occurs in the temperature range of 800 – 1200 °C, with higher lead removal rate. Intensive lead removal was observed at temperature above 1000 °C, while intensive zinc removal occurs at temperature above 1200 °C. Clarifying isothermal experiments performed in the Tamman furnace showed that lead complete transition to the gas phase was achieved at a temperature of 1100 °C (holding time – 12 min) and at a temperature of 1200 °C (holding time – 6 min or more). At the same time, zinc removal was observed in the amount of 14.4 % ratio and 32.2 % ratio, respectively, which allows us to conclude that it is possible to consistently obtain two products: lead and zinc mixture and zinc not contaminated with lead. When comparing experimental and thermodynamic modeling data, the reactions that are most likely to occur during the carbon reduction of lead- and zinc-containing phases were determined.
{"title":"Lead and zinc selective extraction from EAF dust while heating in resistance furnace with flowing argon","authors":"N. V. Podusovskaya, O. Komolova, K. Grigorovich, A. Pavlov, V. Aksenova, B. Rumyantsev, M. Zheleznyi","doi":"10.17073/0368-0797-2023-3-344-355","DOIUrl":"https://doi.org/10.17073/0368-0797-2023-3-344-355","url":null,"abstract":"The elemental and phase compositions of electric arc furnace (EAF) dust from PJSC Severstal were studied. We carried out the thermodynamic modeling of zinc and lead selective extraction process and determined its possible mechanisms. EAF dust was heated in the temperature range of 20 – 1300 °C in vacuum resistance furnace and the Tamman furnace with flowing argon. Experiments in the vacuum resistance furnace with linear heating showed that lead and zinc removal from the sample occurs in the temperature range of 800 – 1200 °C, with higher lead removal rate. Intensive lead removal was observed at temperature above 1000 °C, while intensive zinc removal occurs at temperature above 1200 °C. Clarifying isothermal experiments performed in the Tamman furnace showed that lead complete transition to the gas phase was achieved at a temperature of 1100 °C (holding time – 12 min) and at a temperature of 1200 °C (holding time – 6 min or more). At the same time, zinc removal was observed in the amount of 14.4 % ratio and 32.2 % ratio, respectively, which allows us to conclude that it is possible to consistently obtain two products: lead and zinc mixture and zinc not contaminated with lead. When comparing experimental and thermodynamic modeling data, the reactions that are most likely to occur during the carbon reduction of lead- and zinc-containing phases were determined.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83186576","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: 10.17073/0368-0797-2023-3-330-336
L. A. Bolʼshov, S. K. Korneichuk, E. L. Bolʼshova
The authors propose a simple theory of thermodynamic properties of liquid nitrogen solutions in alloys of the Fe – Ni – Cr and Fe – Ni – Mo systems. This theory is analogous to the theory for liquid nitrogen solutions in binary alloys of the Fe – Cr and Fe – Ni systems proposed previously by the authors in 2019 and 2021. The theory is based on lattice model of ternary liquid solutions of the Fe – Ni – Cr and Fe – Ni – Mo systems. The model assumes a FCC lattice. Atoms of Fe, Ni, Cr and Mo are deposed in the sites of the lattice. Nitrogen atoms are located in octahedral interstices. The nitrogen atom interacts only with the metal atoms located in the lattice sites neighboring to it. This interaction is pairwise. It is assumed that the energy of this interaction depends neither on composition nor on temperature. It is supposed that the liquid solutions in the Fe – Ni – Cr and Fe – Ni – Mo systems are perfect. Within the framework of the proposed theory, the relation is obtained that expresses the Wagner interaction coefficient between nitrogen and chromium in liquid nickel-based alloys (varepsilon _{rm{N}}^{{rm{Cr}}})(Ni). The right-hand part of the appropriate formula is a function of the Wagner interaction coefficients between nitrogen and chromium (varepsilon _{rm{N}}^{{rm{Cr}}})(Fe) and between nitrogen and nickel (varepsilon _{rm{N}}^{{rm{Ni}}})(Fe) in liquid iron-based alloys. A similar relation is obtained for the Wagner interaction coefficient between nitrogen and molybdenum in liquid nickel-based alloys (varepsilon _{rm{N}}^{{rm{Mo}}})(Ni). According to the first of these formulas, the value (varepsilon _{rm{N}}^{{rm{Cr}}})(Ni) = –21,9 at a temperature of 1873 K is calculated. This corresponds to the value of the Langenberg interaction coefficient (e _{rm{N}}^{{rm{Cr}}})(Ni) = –0,108, which coincides with experimental estimate. According to the second formula, the value (varepsilon _{rm{N}}^{{rm{Mo}}})(Ni) = –14,3 is calculated at a temperature 1873 K. This corresponds to the value of the Langenberg interaction coefficient (e _{rm{N}}^{{rm{Cr}}})(Ni) = –0,036, which is in satisfactory agreement with the experimental estimate (varepsilon _{rm{N}}^{{rm{Mo}}})(Ni) = –15,1; (e _{rm{N}}^{{rm{Cr}}})(Ni) = –0,038.
{"title":"Wagner interaction coefficients of nitrogen with chromium and molibdenum in liquid nickel-based alloys","authors":"L. A. Bolʼshov, S. K. Korneichuk, E. L. Bolʼshova","doi":"10.17073/0368-0797-2023-3-330-336","DOIUrl":"https://doi.org/10.17073/0368-0797-2023-3-330-336","url":null,"abstract":"The authors propose a simple theory of thermodynamic properties of liquid nitrogen solutions in alloys of the Fe – Ni – Cr and Fe – Ni – Mo systems. This theory is analogous to the theory for liquid nitrogen solutions in binary alloys of the Fe – Cr and Fe – Ni systems proposed previously by the authors in 2019 and 2021. The theory is based on lattice model of ternary liquid solutions of the Fe – Ni – Cr and Fe – Ni – Mo systems. The model assumes a FCC lattice. Atoms of Fe, Ni, Cr and Mo are deposed in the sites of the lattice. Nitrogen atoms are located in octahedral interstices. The nitrogen atom interacts only with the metal atoms located in the lattice sites neighboring to it. This interaction is pairwise. It is assumed that the energy of this interaction depends neither on composition nor on temperature. It is supposed that the liquid solutions in the Fe – Ni – Cr and Fe – Ni – Mo systems are perfect. Within the framework of the proposed theory, the relation is obtained that expresses the Wagner interaction coefficient between nitrogen and chromium in liquid nickel-based alloys (varepsilon _{rm{N}}^{{rm{Cr}}})(Ni). The right-hand part of the appropriate formula is a function of the Wagner interaction coefficients between nitrogen and chromium (varepsilon _{rm{N}}^{{rm{Cr}}})(Fe) and between nitrogen and nickel (varepsilon _{rm{N}}^{{rm{Ni}}})(Fe) in liquid iron-based alloys. A similar relation is obtained for the Wagner interaction coefficient between nitrogen and molybdenum in liquid nickel-based alloys (varepsilon _{rm{N}}^{{rm{Mo}}})(Ni). According to the first of these formulas, the value (varepsilon _{rm{N}}^{{rm{Cr}}})(Ni) = –21,9 at a temperature of 1873 K is calculated. This corresponds to the value of the Langenberg interaction coefficient (e _{rm{N}}^{{rm{Cr}}})(Ni) = –0,108, which coincides with experimental estimate. According to the second formula, the value (varepsilon _{rm{N}}^{{rm{Mo}}})(Ni) = –14,3 is calculated at a temperature 1873 K. This corresponds to the value of the Langenberg interaction coefficient (e _{rm{N}}^{{rm{Cr}}})(Ni) = –0,036, which is in satisfactory agreement with the experimental estimate (varepsilon _{rm{N}}^{{rm{Mo}}})(Ni) = –15,1; (e _{rm{N}}^{{rm{Cr}}})(Ni) = –0,038.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"105 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86194899","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 : 2023-06-28DOI: 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}
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