Pub Date : 2023-12-29DOI: 10.17073/0368-0797-2023-6-750-759
S. B. Gamanyuk, D. Rutskii, N. A. Zyuban, M. Kirilichev, M. Nikitin
The paper presents the results of a laboratory study of the effect of refilling the ingot knock-off head with melt in a certain time interval after pouring the ingot body on solidification and structure formation of the model ingot. The research was carried out by the method of physical (cold) modeling for which a laboratory installation (casting form-mold) was developed and manufactured. It allows visually studying the processes occurring during solidification and structure formation on a 19.6-ton model ingot. We used sodium sulfuric acid (crystalline hyposulfite) as a modeling solution. Correspondence of the processes occurring on the model and in real conditions of industrial ingots casting was evaluated using similarity criteria obtained on the basis of dimension theory with analysis of physico-chemical processes occurring during casting and crystallization of the ingot. Casting of the melt into the casting form-mold was downhill. In order to assess changes in the temperature field during casting and crystallization of the ingot in the entire solidification time, we performed thermometry of the mold model surface. Analysis of the conducted studies results showed that refilling the melt before 40 min leads to stimulation of early settling of crystals (“rain of crystals”), which contributes to an increase in the crystallization directivity in vertical direction. It was established that in a conventional ingot up to 40 min solidification proceeds by a sequential mechanism, and after that the crystals begin to settle (“rain of crystals”) and the solidification of the ingot passes through a volume-sequential mechanism. Refilling the ingot knock-off head with melt 40 min after pouring the ingot body contributed to the continuation of the sequential mechanism of ingot solidification, which led to the formation of a monolithic defect-free structure in the ingot body and the least development of shrinkage shell in the knock-off head. The results obtained make it possible to develop a technology for differentiated ingots casting when filling their knock-off heads with melt in a certain time interval after pouring the ingot body, which will affect the process of metal structure formation and reduce defective zones.
{"title":"Physical modeling of the effect of refilling the melt into an ingot knock-off head on solidification and structure formation","authors":"S. B. Gamanyuk, D. Rutskii, N. A. Zyuban, M. Kirilichev, M. Nikitin","doi":"10.17073/0368-0797-2023-6-750-759","DOIUrl":"https://doi.org/10.17073/0368-0797-2023-6-750-759","url":null,"abstract":"The paper presents the results of a laboratory study of the effect of refilling the ingot knock-off head with melt in a certain time interval after pouring the ingot body on solidification and structure formation of the model ingot. The research was carried out by the method of physical (cold) modeling for which a laboratory installation (casting form-mold) was developed and manufactured. It allows visually studying the processes occurring during solidification and structure formation on a 19.6-ton model ingot. We used sodium sulfuric acid (crystalline hyposulfite) as a modeling solution. Correspondence of the processes occurring on the model and in real conditions of industrial ingots casting was evaluated using similarity criteria obtained on the basis of dimension theory with analysis of physico-chemical processes occurring during casting and crystallization of the ingot. Casting of the melt into the casting form-mold was downhill. In order to assess changes in the temperature field during casting and crystallization of the ingot in the entire solidification time, we performed thermometry of the mold model surface. Analysis of the conducted studies results showed that refilling the melt before 40 min leads to stimulation of early settling of crystals (“rain of crystals”), which contributes to an increase in the crystallization directivity in vertical direction. It was established that in a conventional ingot up to 40 min solidification proceeds by a sequential mechanism, and after that the crystals begin to settle (“rain of crystals”) and the solidification of the ingot passes through a volume-sequential mechanism. Refilling the ingot knock-off head with melt 40 min after pouring the ingot body contributed to the continuation of the sequential mechanism of ingot solidification, which led to the formation of a monolithic defect-free structure in the ingot body and the least development of shrinkage shell in the knock-off head. The results obtained make it possible to develop a technology for differentiated ingots casting when filling their knock-off heads with melt in a certain time interval after pouring the ingot body, which will affect the process of metal structure formation and reduce defective zones.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":" 78","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139144648","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: 10.17073/0368-0797-2023-6-725-732
K. Spiridonova, I. Litovchenko, N. Polekhina, V. Linnik, T. A. Borisenko, V. Chernov, M. Leont'eva-Smirnova
The features of phase transformations of 12 % chromium ferritic-martensitic steel EP-823 under heating and cooling conditions in the temperature range from 30 to 1100 ℃ were studied by the methods of high-temperature X-ray diffraction analysis (XRD) in situ and differential scanning calorimetry (DSC). According to XRD in situ data, upon heating, the temperatures of the beginning and end of the (α → γ) transformation of ferrite (martensite – austenite) are Ac1 ≈ 880 °C, Ac3 ≈ 1000 °C, respectively. Upon cooling, a diffusion (γ → α) transformation occurs with critical points – Аr1 ≈ 860°С (beginning temperature) and Аr3 ≈ 840 °С (end temperature). According to DSC data, during heating, the critical points of the (α → γ) transformation are Ac1 ≈ 840 °C and Ac3 ≈ 900 °C. During cooling, a martensitic (γ → α) transformation is realized with critical points of the beginning of Ms = 344 ℃ and the end of Mf = 212 ℃ of this transformation. The XRD in situ analysis revealed no precipitation of carbide phases under heating and cooling conditions of steel EP-823. Position of the critical points of phase transformations depends on the research method (XRD in situ or DSC), which is determined by the difference in effective (taking into account the time for shooting in the XRD method) heating-cooling rate. The effect of elemental composition on the position of critical points of phase transformations and the formation of structural-phase states of ferritic-martensitic steels is discussed. It is shown that the increased content of ferrite-stabilizing elements (Cr, Mo, Nb) in composition of EP-823 steel, compared with other steels of the same class, expands the region of existence of the ferrite phase, which can contribute to an increase in the temperature of Ac1 .
{"title":"Structural-phase transformations of 12% chromium ferritic-martensitic steel EP-823","authors":"K. Spiridonova, I. Litovchenko, N. Polekhina, V. Linnik, T. A. Borisenko, V. Chernov, M. Leont'eva-Smirnova","doi":"10.17073/0368-0797-2023-6-725-732","DOIUrl":"https://doi.org/10.17073/0368-0797-2023-6-725-732","url":null,"abstract":"The features of phase transformations of 12 % chromium ferritic-martensitic steel EP-823 under heating and cooling conditions in the temperature range from 30 to 1100 ℃ were studied by the methods of high-temperature X-ray diffraction analysis (XRD) in situ and differential scanning calorimetry (DSC). According to XRD in situ data, upon heating, the temperatures of the beginning and end of the (α → γ) transformation of ferrite (martensite – austenite) are Ac1 ≈ 880 °C, Ac3 ≈ 1000 °C, respectively. Upon cooling, a diffusion (γ → α) transformation occurs with critical points – Аr1 ≈ 860°С (beginning temperature) and Аr3 ≈ 840 °С (end temperature). According to DSC data, during heating, the critical points of the (α → γ) transformation are Ac1 ≈ 840 °C and Ac3 ≈ 900 °C. During cooling, a martensitic (γ → α) transformation is realized with critical points of the beginning of Ms = 344 ℃ and the end of Mf = 212 ℃ of this transformation. The XRD in situ analysis revealed no precipitation of carbide phases under heating and cooling conditions of steel EP-823. Position of the critical points of phase transformations depends on the research method (XRD in situ or DSC), which is determined by the difference in effective (taking into account the time for shooting in the XRD method) heating-cooling rate. The effect of elemental composition on the position of critical points of phase transformations and the formation of structural-phase states of ferritic-martensitic steels is discussed. It is shown that the increased content of ferrite-stabilizing elements (Cr, Mo, Nb) in composition of EP-823 steel, compared with other steels of the same class, expands the region of existence of the ferrite phase, which can contribute to an increase in the temperature of Ac1 .","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":" 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139142672","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: 10.17073/0368-0797-2023-6-681-687
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 : 2023-07-03DOI: 10.17073/0368-0797-2023-3-367-375
V. V. Myl’nikov, E. Dmitriev
For trouble-free operation without loss of elastic and inelastic properties of particularly critical elements of electrical-to-mechanical vibration converters during a long period of cyclic operation, it is necessary, in addition to studying the fatigue characteristics of materials used for their manufacture, to study these alloys for frequency stability, since minor deviations in the frequency of natural oscillations lead to unacceptable errors in the operation of such high-precision products. To carry out such studies, we developed and constructed an original installation, in which sinusoidal loading is carried out according to the “soft” scheme of flat samples cantilever bending operating in self-oscillation mode. The frequency of cyclic loading in this installation is generated by current pulses, which are a response to the frequency of the test sample natural oscillations converted using electronics. As a result, frequency equality is achieved in the test process. An algorithm for calculating stresses depending on the loading amplitude of steel samples of different geometric shapes was developed. It is shown that the stress on the sample calculated by the deformation amplitude in all cases is 8 – 10 % higher than the stress calculated by the force, regardless of the shape of the proposed samples. To verify the proposed research method, martensitic-aging steel was tested at loads close to the fatigue limit, since frequency stability in this range is of great interest. We obtained the frequency characteristics in the multi-cycle test area. It was determined that with an operating time of 50 million loading cycles, the frequency change was 0.75 Hz. The dynamics of frequency stability was revealed: the frequency changed most intensively during the first 10 million loading cycles, during this time the frequency changed by 0.54 Hz.
{"title":"A method for studying the frequency stability of materials during tests for multi-cycle fatigue of steel","authors":"V. V. Myl’nikov, E. Dmitriev","doi":"10.17073/0368-0797-2023-3-367-375","DOIUrl":"https://doi.org/10.17073/0368-0797-2023-3-367-375","url":null,"abstract":"For trouble-free operation without loss of elastic and inelastic properties of particularly critical elements of electrical-to-mechanical vibration converters during a long period of cyclic operation, it is necessary, in addition to studying the fatigue characteristics of materials used for their manufacture, to study these alloys for frequency stability, since minor deviations in the frequency of natural oscillations lead to unacceptable errors in the operation of such high-precision products. To carry out such studies, we developed and constructed an original installation, in which sinusoidal loading is carried out according to the “soft” scheme of flat samples cantilever bending operating in self-oscillation mode. The frequency of cyclic loading in this installation is generated by current pulses, which are a response to the frequency of the test sample natural oscillations converted using electronics. As a result, frequency equality is achieved in the test process. An algorithm for calculating stresses depending on the loading amplitude of steel samples of different geometric shapes was developed. It is shown that the stress on the sample calculated by the deformation amplitude in all cases is 8 – 10 % higher than the stress calculated by the force, regardless of the shape of the proposed samples. To verify the proposed research method, martensitic-aging steel was tested at loads close to the fatigue limit, since frequency stability in this range is of great interest. We obtained the frequency characteristics in the multi-cycle test area. It was determined that with an operating time of 50 million loading cycles, the frequency change was 0.75 Hz. The dynamics of frequency stability was revealed: the frequency changed most intensively during the first 10 million loading cycles, during this time the frequency changed by 0.54 Hz.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"78 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90853209","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: 10.17073/0368-0797-2023-3-337-343
A. D. Khoroshilov, S. A. Somov, V. D. Katolikov, V. A. Murysev, R. E. Bocherikov, M. R. Yarmukhametov
Aluminum is one of the most common deoxidizers; when it is used in the melt, refractory inclusions of alumina are formed. The presence of these non-metallic inclusions negatively affects the purity of liquid steel, mechanical properties, makes casting difficult due to tightening of the steel-pouring fittings. The modification of alumina inclusions with calcium promotes the formation of liquid calcium aluminates, which leads to an acceleration of their removal from the metal due to a higher ascent rate. Having a high affinity for sulfur, calcium reduces its harmful effect by binding it with the formation of calcium sulfides, reducing the anisotropy of steel properties during further rolling. For steel treatment with calcium, injection wires with a calcium-containing filler are used. As a filler can be used: electrolytic calcium, silicocalcium, aluminum-tremic calcium, or ferrocalcium. The paper describes results of the tests carried out on a calcium-containing wire filled with electrolytic calcium and silicocalcium. It is shown that the consumption of calcium when using silicocalcium wire is on average 35 % higher in comparison with calcium injection wire filled with electrolytic calcium. The calcium recovery rate for different steel grades was evaluated using calcium-containing wires of different designs and filler. In this work, the steel pourability was analyzed. As a determining parameter, dependence of change in position of the tundish stopper rod on calcium content in the metal was considered in the sample from CCM. It was established that a wire filled with electrolytic calcium shows a more effective result in comparison with a silicocalcium wire.
{"title":"Using calcium-containing injection wire filled with electrolytic calcium in steel ladle treatment","authors":"A. D. Khoroshilov, S. A. Somov, V. D. Katolikov, V. A. Murysev, R. E. Bocherikov, M. R. Yarmukhametov","doi":"10.17073/0368-0797-2023-3-337-343","DOIUrl":"https://doi.org/10.17073/0368-0797-2023-3-337-343","url":null,"abstract":"Aluminum is one of the most common deoxidizers; when it is used in the melt, refractory inclusions of alumina are formed. The presence of these non-metallic inclusions negatively affects the purity of liquid steel, mechanical properties, makes casting difficult due to tightening of the steel-pouring fittings. The modification of alumina inclusions with calcium promotes the formation of liquid calcium aluminates, which leads to an acceleration of their removal from the metal due to a higher ascent rate. Having a high affinity for sulfur, calcium reduces its harmful effect by binding it with the formation of calcium sulfides, reducing the anisotropy of steel properties during further rolling. For steel treatment with calcium, injection wires with a calcium-containing filler are used. As a filler can be used: electrolytic calcium, silicocalcium, aluminum-tremic calcium, or ferrocalcium. The paper describes results of the tests carried out on a calcium-containing wire filled with electrolytic calcium and silicocalcium. It is shown that the consumption of calcium when using silicocalcium wire is on average 35 % higher in comparison with calcium injection wire filled with electrolytic calcium. The calcium recovery rate for different steel grades was evaluated using calcium-containing wires of different designs and filler. In this work, the steel pourability was analyzed. As a determining parameter, dependence of change in position of the tundish stopper rod on calcium content in the metal was considered in the sample from CCM. It was established that a wire filled with electrolytic calcium shows a more effective result in comparison with a silicocalcium wire.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86289372","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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