Pub Date : 2022-12-31DOI: 10.17073/0368-0797-2022-12-879-886
E. E. Deryugin, N. Narkevich, Yu. F. Gomorova
The paper studies the influence of boundary conditions and the loading rate on the strain behavior and fracture of Cr – Mn – C – N austenitic steel in the cast state without additional heat treatment. Regularities of steel strain and fracture were analyzed on the basis of three-point bending test data of square-section samples with and without a notch, placed with a rib on supports. In addition to the initial stage of the steel elastic strain, this unconventional arrangement of the sample on supports enabled the detection of two more stages of strain development under the effect of an external applied force: the stage of nonlinear strain and the stage of discontinuous strain preceding the moment of sample failure. As the loading rate increases, it was demonstrated that the fracture resistance and the extent of the nonlin-ear strain stage of the sample with a notch increases, and the extent of the discontinuous strain stage decreases. The sample without a notch has a prolonged nonlinear strain stage and exhibits maximum strength in the absence of the discontinuous stage. The end of the nonlinear strain stage corresponds to the moment of sample failure. A characteristic property of cast steel under the given loading conditions is that the fracture of the sample is brittle, despite the prolonged stage of non-linear strain. Structural metallographic and diffractometric studies have shown that in all tests the steel fracture is brittle with-out traces of plastic yield. The nonlinear strain stage of steel is determined not by dislocation plastic yield, but by the mechanism of γ → αʹ transformation in austenitic interlayers between nitride and car-bide particles under the effect of an external applied force. The discontinuous strain stage of steel is associated with the process of stable crack propagation across the sample.
研究了边界条件和加载速率对铸态Cr - Mn - C - N奥氏体钢应变行为和断口的影响。根据带肋支承的带缺口和不带缺口的方形截面试样三点弯曲试验数据，分析了钢的应变和断裂规律。除了钢弹性应变的初始阶段外，这种非传统的支撑试样排列方式还可以检测到在外力作用下的另外两个应变发展阶段:非线性应变阶段和试样失效前的不连续应变阶段。结果表明，随着加载速率的增加，带缺口试样的断裂抗力和非线性穗应变阶段增大，不连续应变阶段减小;没有缺口的试样具有延长的非线性应变阶段，在没有不连续阶段时表现出最大的强度。非线性应变阶段的结束对应于试样的破坏时刻。在给定的加载条件下，铸钢的一个特征是试样的断裂是脆性的，尽管非线性应变阶段延长了。组织金相和衍射研究表明，在所有的测试中，钢的断裂是脆的，没有塑性屈服的痕迹。钢的非线性应变阶段不是由位错塑性屈服决定的，而是由外力作用下氮化物与车相颗粒之间奥氏体层γ→α→相变机制决定的。钢的不连续应变阶段与裂纹在试样上的稳定扩展过程有关。
{"title":"Deformation and fracture of Cr – Mn – C – N steel in as-cast condition","authors":"E. E. Deryugin, N. Narkevich, Yu. F. Gomorova","doi":"10.17073/0368-0797-2022-12-879-886","DOIUrl":"https://doi.org/10.17073/0368-0797-2022-12-879-886","url":null,"abstract":"The paper studies the influence of boundary conditions and the loading rate on the strain behavior and fracture of Cr – Mn – C – N austenitic steel in the cast state without additional heat treatment. Regularities of steel strain and fracture were analyzed on the basis of three-point bending test data of square-section samples with and without a notch, placed with a rib on supports. In addition to the initial stage of the steel elastic strain, this unconventional arrangement of the sample on supports enabled the detection of two more stages of strain development under the effect of an external applied force: the stage of nonlinear strain and the stage of discontinuous strain preceding the moment of sample failure. As the loading rate increases, it was demonstrated that the fracture resistance and the extent of the nonlin-ear strain stage of the sample with a notch increases, and the extent of the discontinuous strain stage decreases. The sample without a notch has a prolonged nonlinear strain stage and exhibits maximum strength in the absence of the discontinuous stage. The end of the nonlinear strain stage corresponds to the moment of sample failure. A characteristic property of cast steel under the given loading conditions is that the fracture of the sample is brittle, despite the prolonged stage of non-linear strain. Structural metallographic and diffractometric studies have shown that in all tests the steel fracture is brittle with-out traces of plastic yield. The nonlinear strain stage of steel is determined not by dislocation plastic yield, but by the mechanism of γ → αʹ transformation in austenitic interlayers between nitride and car-bide particles under the effect of an external applied force. The discontinuous strain stage of steel is associated with the process of stable crack propagation across the sample.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"27 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83318771","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 : 2022-12-31DOI: 10.17073/0368-0797-2022-12-851-860
L. Korotkova, A. Korotkov
The authors analyzed the state of tool production in Russia. The main manufacturing companies and the main brands of materials used in the production of domestic tools are highlighted. Powder high-speed steels are practically not used in the domestic market, but they are widely distributed in the foreign market of tool steels due to their significant advantages in terms of basic and technological properties (including the possibility of using high-carbon and high-alloy high-speed steels). There is a new group of economically alloyed tungsten-free high-speed steels with a high content of carbon and vanadium, which are practically impossible to manufacture and apply in our traditional technology due to low technological properties. The authors give recommendations on the technology of manufacturing such steels by powder metallurgy and on the modes of their heat treatment. The paper studies a set of properties of these steels, including: basic mechanical properties (hardness, bending strength, toughness, and heat resistance), basic technological properties (pressure, cutting, grinding) and operational properties (evaluated by tool durability during turning). Structural and phase compositions of the steels and their influence on the basic and technological properties were investigated. The compaction mode affects the density of the billets. The paper presents distribution of alloying elements in the microstructure of powder high-speed steel and results of their relative grindability. Also the durability of tools was tested. There are significant advantages of high-carbon high-vanadium high-speed steels, especially in terms of technological properties, compared with traditional high-speed steels. It is possible to produce high-alloy tool steels using inexpensive carbide-forming alloying elements. The steels under consideration can be used to manufacture a wide range of tools, including hot-forming die tools. The use of powder technology opens up the prospect of developing universal economically alloyed powder tool steels.
{"title":"Influence of production technology of powder high-speed steels on the complex of formed properties","authors":"L. Korotkova, A. Korotkov","doi":"10.17073/0368-0797-2022-12-851-860","DOIUrl":"https://doi.org/10.17073/0368-0797-2022-12-851-860","url":null,"abstract":"The authors analyzed the state of tool production in Russia. The main manufacturing companies and the main brands of materials used in the production of domestic tools are highlighted. Powder high-speed steels are practically not used in the domestic market, but they are widely distributed in the foreign market of tool steels due to their significant advantages in terms of basic and technological properties (including the possibility of using high-carbon and high-alloy high-speed steels). There is a new group of economically alloyed tungsten-free high-speed steels with a high content of carbon and vanadium, which are practically impossible to manufacture and apply in our traditional technology due to low technological properties. The authors give recommendations on the technology of manufacturing such steels by powder metallurgy and on the modes of their heat treatment. The paper studies a set of properties of these steels, including: basic mechanical properties (hardness, bending strength, toughness, and heat resistance), basic technological properties (pressure, cutting, grinding) and operational properties (evaluated by tool durability during turning). Structural and phase compositions of the steels and their influence on the basic and technological properties were investigated. The compaction mode affects the density of the billets. The paper presents distribution of alloying elements in the microstructure of powder high-speed steel and results of their relative grindability. Also the durability of tools was tested. There are significant advantages of high-carbon high-vanadium high-speed steels, especially in terms of technological properties, compared with traditional high-speed steels. It is possible to produce high-alloy tool steels using inexpensive carbide-forming alloying elements. The steels under consideration can be used to manufacture a wide range of tools, including hot-forming die tools. The use of powder technology opens up the prospect of developing universal economically alloyed powder tool steels.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84206515","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 : 2022-12-31DOI: 10.17073/0368-0797-2022-12-895-903
G. G. Mikhailov, L. Makrovets, I. V. Bakin
The use of complex strontium-containing alloys with alkaline-earth metals for steel out-of-furnace treatment makes it possible to increase the efficiency of the refining process and steel modifying. In this work based on the binary phase diagrams of SrO – CaO, SrO – Al2O3 , Al2O3 – CaO binary systems and data on possibility of the solid solution formation, the phase diagram of the SrO – Al2O3 – CaO system is modeled in the temperature range 1600 – 2600 °С. When constructing liquidus lines, the theories of perfect solutions (for solid solutions of strontium and calcium aluminates), regular solutions (for solid solutions of oxides) and irregular ionic solutions (for oxide melt) were used to calculate the activity of components. Thermodynamic analysis of the Fe – Sr – Ca – Al – O system was carried out as applied to the refining steel processes with alloys containing calcium and strontium at a temperature of 1600 °C. The simulation results showed that in in the process of refining the aluminium-deoxidized steel, a complex mechanism of interaction of active elements with oxygen will be realized. The interaction of calcium and strontium with oxygen occurs both for elements dissolved in iron and along the boundary of the gas phase containing calcium and strontium with the liquid iron melt. As a result of the interaction of calcium and strontium with oxygen in the presence of aluminium (0.05 %), the probability of formation of liquid oxide melts SrO – Al2O3 – CaO is high, which greatly facilitates the removal of reaction products from the melt. The resulting non-metallic inclusions are most likely to be complex calcium and strontium aluminates, which, due to the presence of strontium, are easily assimilated by slag. The formation of undesirable corundum inclusions during metal processing with complex alloys containing strontium and calcium is unlikely.
将含锶复合合金与碱土金属用于钢的炉外处理，可以提高炼钢工艺和钢的改性效率。在这个工作的基础上,“二元相图的SrO” 曹,地面读数 氧化铝,氧化铝 —— 曹二元系统和数据的可能性固溶体的形成,“相图的SrO” - 氧化铝 曹系统建模在温度范围1600 - 2600°С。在构造液相线时，采用完美溶液理论(适用于锶和铝酸钙的固溶体)、规则溶液理论(适用于氧化物的固溶体)和不规则离子溶液理论(适用于氧化物熔体)计算组分的活度。对Fe - Sr - Ca - Al - - O体系在1600℃含钙锶合金炼钢过程中进行了热力学分析。模拟结果表明，在铝脱氧钢精炼过程中，活性元素与氧相互作用的复杂机制将得以实现。钙和锶与氧的相互作用既发生在溶解在铁中的元素中，也发生在含钙和锶的气相与液态铁熔体的边界上。在铝的存在下(0.05%)，由于钙、锶与氧的相互作用，形成液态氧化物熔体SrO - Al2O3 - CaO的概率很高，这极大地促进了熔体中反应产物的去除。所产生的非金属夹杂物很可能是复合的钙和锶铝酸盐，由于锶的存在，很容易被炉渣同化。在含有锶和钙的复杂合金的金属加工过程中，不太可能形成不良的刚玉夹杂物。
{"title":"Strontium effect on the nature of phase equilibria in liquid metal containing calcium and aluminum","authors":"G. G. Mikhailov, L. Makrovets, I. V. Bakin","doi":"10.17073/0368-0797-2022-12-895-903","DOIUrl":"https://doi.org/10.17073/0368-0797-2022-12-895-903","url":null,"abstract":"The use of complex strontium-containing alloys with alkaline-earth metals for steel out-of-furnace treatment makes it possible to increase the efficiency of the refining process and steel modifying. In this work based on the binary phase diagrams of SrO – CaO, SrO – Al2O3 , Al2O3 – CaO binary systems and data on possibility of the solid solution formation, the phase diagram of the SrO – Al2O3 – CaO system is modeled in the temperature range 1600 – 2600 °С. When constructing liquidus lines, the theories of perfect solutions (for solid solutions of strontium and calcium aluminates), regular solutions (for solid solutions of oxides) and irregular ionic solutions (for oxide melt) were used to calculate the activity of components. Thermodynamic analysis of the Fe – Sr – Ca – Al – O system was carried out as applied to the refining steel processes with alloys containing calcium and strontium at a temperature of 1600 °C. The simulation results showed that in in the process of refining the aluminium-deoxidized steel, a complex mechanism of interaction of active elements with oxygen will be realized. The interaction of calcium and strontium with oxygen occurs both for elements dissolved in iron and along the boundary of the gas phase containing calcium and strontium with the liquid iron melt. As a result of the interaction of calcium and strontium with oxygen in the presence of aluminium (0.05 %), the probability of formation of liquid oxide melts SrO – Al2O3 – CaO is high, which greatly facilitates the removal of reaction products from the melt. The resulting non-metallic inclusions are most likely to be complex calcium and strontium aluminates, which, due to the presence of strontium, are easily assimilated by slag. The formation of undesirable corundum inclusions during metal processing with complex alloys containing strontium and calcium is unlikely.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"194 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88061117","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 : 2022-11-22DOI: 10.17073/0368-0797-2022-11-758-768
S. Zhilin, N. Bogdanova, O. N. Komarov
The growth in metal intensity of industrial production and the volume of consumption of finished metal products determine the relevance of development and research of energy efficient technological processes aimed at reducing costs by reducing the number of operations while maintaining product performance. In mechanical engineering, the problem of obtaining blanks with increased dimensional and geometric accuracy and complex configuration is solved by using a common method of investment casting. Expansion of the use of such technological approach to produce blanks in mechanical engineering is hindered by a number of physical phenomena associated with the thermal expansion of investment and ceramic materials, which leads to an increase in the product final cost. A significant number of defect-forming factors can be eliminated by applying an innovative solution consisting in the formation of porous removable models by compacting mixtures based on waxy materials. This solves the problem of material shrinkage and increases the crack resistance of ceramic molds, which significantly reduces the share of machining in the overall volume of technological operations. Technical tests of the new method have revealed the reason why the machining of castings cannot be completely eliminated at present. The problem mainly lies in elastic response of compacted material of the model mixture, which, in some cases, affects the increase in the compacts size. This paper considers the effect of initial packing of spherical-shaped elements simulating one- and two-component model mixtures on the stress-strain state of a powder body subjected to unilateral compaction in a rigid cylindrical matrix to technologically justified density values. The results of the experiment are presented in the form of stress-strain relations. Preferable conditions of compact formation with minimal values of elastic response of the compacted material are considered.
{"title":"Experimental simulation of volumetric compacts formation from spherical waxy elements","authors":"S. Zhilin, N. Bogdanova, O. N. Komarov","doi":"10.17073/0368-0797-2022-11-758-768","DOIUrl":"https://doi.org/10.17073/0368-0797-2022-11-758-768","url":null,"abstract":"The growth in metal intensity of industrial production and the volume of consumption of finished metal products determine the relevance of development and research of energy efficient technological processes aimed at reducing costs by reducing the number of operations while maintaining product performance. In mechanical engineering, the problem of obtaining blanks with increased dimensional and geometric accuracy and complex configuration is solved by using a common method of investment casting. Expansion of the use of such technological approach to produce blanks in mechanical engineering is hindered by a number of physical phenomena associated with the thermal expansion of investment and ceramic materials, which leads to an increase in the product final cost. A significant number of defect-forming factors can be eliminated by applying an innovative solution consisting in the formation of porous removable models by compacting mixtures based on waxy materials. This solves the problem of material shrinkage and increases the crack resistance of ceramic molds, which significantly reduces the share of machining in the overall volume of technological operations. Technical tests of the new method have revealed the reason why the machining of castings cannot be completely eliminated at present. The problem mainly lies in elastic response of compacted material of the model mixture, which, in some cases, affects the increase in the compacts size. This paper considers the effect of initial packing of spherical-shaped elements simulating one- and two-component model mixtures on the stress-strain state of a powder body subjected to unilateral compaction in a rigid cylindrical matrix to technologically justified density values. The results of the experiment are presented in the form of stress-strain relations. Preferable conditions of compact formation with minimal values of elastic response of the compacted material are considered.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"31 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73290997","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 : 2022-11-22DOI: 10.17073/0368-0797-2022-11-814-823
S. B. Gamanyuk, D. Rutskii, N. A. Zyuban, M. Kirilichev, M. Nikitin, D. Gurulev
The article presents the results of evaluation of the impact of teeming method and rate on solidification and formation of the axial zone of large ingots. The research is based on a physical simulation. With this aim a laboratory-scale plant (a crystallization mould) was designed and built which enabled to visualize and monitor solidification and structural formation of the model ingots. Sodium thiosulphate (crystal hyposulphite) – Na2S2O3·5H2O was used as a modeling solution. Matching of the processes in the model and in real industrial conditions of ingot teeming was assessed with similarity criteria obtained on the basis of the dimension theory with consideration of the physical and chemical processes in the ingot during its teeming and crystallization. Two methods – downhill casting and uphill casting – were used to teem the melt into the mould. During teeming the geometry and technological parameters of the model ingots remained unchanged while the teeming rate was altered. Length and medium width of the model ingot axial zone were measured. The thermal profiling of the surface of the mould model was monitored over the entire period of solidification to evaluate the thermal field alteration while the ingot was teemed and crystallized. Thermal imaging processing made it possible to observe temperature changes of the surface of the model mould from top to bottom for downhill cast ingots teemed at different rates. The results obtained demonstrate that teeming rate has a noticeable impact on the axial zone length. It was established that a decreased rate leads to an increased directionality of crystallization and improvement of the ingot axial zone structure.
{"title":"Application of physical simulation to evaluate the impact of teeming method and rate on axial zone formation of large ingots","authors":"S. B. Gamanyuk, D. Rutskii, N. A. Zyuban, M. Kirilichev, M. Nikitin, D. Gurulev","doi":"10.17073/0368-0797-2022-11-814-823","DOIUrl":"https://doi.org/10.17073/0368-0797-2022-11-814-823","url":null,"abstract":"The article presents the results of evaluation of the impact of teeming method and rate on solidification and formation of the axial zone of large ingots. The research is based on a physical simulation. With this aim a laboratory-scale plant (a crystallization mould) was designed and built which enabled to visualize and monitor solidification and structural formation of the model ingots. Sodium thiosulphate (crystal hyposulphite) – Na2S2O3·5H2O was used as a modeling solution. Matching of the processes in the model and in real industrial conditions of ingot teeming was assessed with similarity criteria obtained on the basis of the dimension theory with consideration of the physical and chemical processes in the ingot during its teeming and crystallization. Two methods – downhill casting and uphill casting – were used to teem the melt into the mould. During teeming the geometry and technological parameters of the model ingots remained unchanged while the teeming rate was altered. Length and medium width of the model ingot axial zone were measured. The thermal profiling of the surface of the mould model was monitored over the entire period of solidification to evaluate the thermal field alteration while the ingot was teemed and crystallized. Thermal imaging processing made it possible to observe temperature changes of the surface of the model mould from top to bottom for downhill cast ingots teemed at different rates. The results obtained demonstrate that teeming rate has a noticeable impact on the axial zone length. It was established that a decreased rate leads to an increased directionality of crystallization and improvement of the ingot axial zone structure.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"259 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76796695","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 : 2022-11-22DOI: 10.17073/0368-0797-2022-11-778-785
S. Albul, O. Kobelev, A. Radyuk, A. Titlyanov, I. A. Levitskii
The purpose of this work was to analyze the effect of a heat-insulating insert, as well as the flow rate and temperature of natural gas on the processes occurring in blast channel of an air tuyere. The paper analyzes the results of industrial and numerical experiments obtained by different researchers on the use of various methods for increasing the completeness of combustion reaction within the air tuyere of natural gas (NG) fed into it: increase of NG flow rate; increase of NG temperature; the use of heat-insulating inserts installed in the inner glass of the air tuyere. Using the Ansys Fluent software complex, the effect of a heat-insulating insert and increase in NG flow rate on the temperature and composition of gases leaving the tuyere of blast furnace no. 5 of PJSC Severstal was studied. It was found that with an increase in NG flow rate from 0.283 to 0.328 kg/s, the temperature of the gas medium at the tuyere outlet decreases by 6 °С for the variant without an insert and increases by 3 °С for the variant with it. When studying the effect of a heat-insulating insert and increase in NG temperature (in different combinations) on the processes occurring in a tuyere, it was found that temperature of the gaseous medium at the tuyere outlet in case of using a heat-insulating insert without NG heating is slightly higher than when NG is heated to 200 °С without inserts. However, the effect of NG heating in the presence of an insert is significantly higher than without it – there is mutual amplification of two factors influencing the completeness of NG combustion within the tuyere, accompanied by protection of the tuyere inner nozzle from burnout.
{"title":"Effect of natural gas flow rate and temperature on the processes occurring in a blast furnace tuyere with heat-insulating insert in blast channel","authors":"S. Albul, O. Kobelev, A. Radyuk, A. Titlyanov, I. A. Levitskii","doi":"10.17073/0368-0797-2022-11-778-785","DOIUrl":"https://doi.org/10.17073/0368-0797-2022-11-778-785","url":null,"abstract":"The purpose of this work was to analyze the effect of a heat-insulating insert, as well as the flow rate and temperature of natural gas on the processes occurring in blast channel of an air tuyere. The paper analyzes the results of industrial and numerical experiments obtained by different researchers on the use of various methods for increasing the completeness of combustion reaction within the air tuyere of natural gas (NG) fed into it: increase of NG flow rate; increase of NG temperature; the use of heat-insulating inserts installed in the inner glass of the air tuyere. Using the Ansys Fluent software complex, the effect of a heat-insulating insert and increase in NG flow rate on the temperature and composition of gases leaving the tuyere of blast furnace no. 5 of PJSC Severstal was studied. It was found that with an increase in NG flow rate from 0.283 to 0.328 kg/s, the temperature of the gas medium at the tuyere outlet decreases by 6 °С for the variant without an insert and increases by 3 °С for the variant with it. When studying the effect of a heat-insulating insert and increase in NG temperature (in different combinations) on the processes occurring in a tuyere, it was found that temperature of the gaseous medium at the tuyere outlet in case of using a heat-insulating insert without NG heating is slightly higher than when NG is heated to 200 °С without inserts. However, the effect of NG heating in the presence of an insert is significantly higher than without it – there is mutual amplification of two factors influencing the completeness of NG combustion within the tuyere, accompanied by protection of the tuyere inner nozzle from burnout.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87689105","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 : 2022-11-22DOI: 10.17073/0368-0797-2022-11-806-813
A. Lebedev, V. S. Shuiskaya
The main components of metallurgical slags are iron compounds, which are extracted by reduction smelting. There are several types of this process with obtaining various products based on iron and slags of various compositions (aluminum-calcium self-disintegrating), etc. The mode of smelting and cooling of alumocalcium slag, formed during melting in the furnace, should ensure the most complete spontaneous crumbling of it, as well as high rates of extraction of REM from it. Synthetic slags similar in phase composition to industrial samples after smelting of iron-containing ores were selected for the experiments. The simulated samples correspond to the region of primary crystallization of bicalcium silicate on the triple state diagram of CaO – SiO2 – Al2O3 system. The slag after crumbling was subjected to a sieve analysis using a mechanical sieve. In the experiments, slags with a silicon module k = 2.0 were used, which actively crumbled during their cooling. With an increase in the silicon module, the crumbling deteriorates. It was established that it is impossible to precisely limit the areas of compositions of crumbling slags at certain cooling rates. The conducted studies showed that the crumblability of slags improves as it approaches the center of the bicalcium silicate region. The composition of slags close to composition of the intersection points of the lines 2CaO·SiO2 – 2CaO·Al2O3 and 2CaO·SiO2 – 12CaO·7Al2O3 with the lines of the permanent silicon module granulometric composition almost does not depend on the cooling rate. The temperature mode from smelting to cooling affects the slags crumblability. The most promising are slags with a silicon module in the range of 2.85 – 3.00, close to the phase triangle 12CaO·7Al2O3 – 2CaO·SiO2 – 2CaO·Al2O3 .
{"title":"Influence of composition and cooling rate of alumocalcium slag on its crumblability","authors":"A. Lebedev, V. S. Shuiskaya","doi":"10.17073/0368-0797-2022-11-806-813","DOIUrl":"https://doi.org/10.17073/0368-0797-2022-11-806-813","url":null,"abstract":"The main components of metallurgical slags are iron compounds, which are extracted by reduction smelting. There are several types of this process with obtaining various products based on iron and slags of various compositions (aluminum-calcium self-disintegrating), etc. The mode of smelting and cooling of alumocalcium slag, formed during melting in the furnace, should ensure the most complete spontaneous crumbling of it, as well as high rates of extraction of REM from it. Synthetic slags similar in phase composition to industrial samples after smelting of iron-containing ores were selected for the experiments. The simulated samples correspond to the region of primary crystallization of bicalcium silicate on the triple state diagram of CaO – SiO2 – Al2O3 system. The slag after crumbling was subjected to a sieve analysis using a mechanical sieve. In the experiments, slags with a silicon module k = 2.0 were used, which actively crumbled during their cooling. With an increase in the silicon module, the crumbling deteriorates. It was established that it is impossible to precisely limit the areas of compositions of crumbling slags at certain cooling rates. The conducted studies showed that the crumblability of slags improves as it approaches the center of the bicalcium silicate region. The composition of slags close to composition of the intersection points of the lines 2CaO·SiO2 – 2CaO·Al2O3 and 2CaO·SiO2 – 12CaO·7Al2O3 with the lines of the permanent silicon module granulometric composition almost does not depend on the cooling rate. The temperature mode from smelting to cooling affects the slags crumblability. The most promising are slags with a silicon module in the range of 2.85 – 3.00, close to the phase triangle 12CaO·7Al2O3 – 2CaO·SiO2 – 2CaO·Al2O3 .","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"41 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86447302","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 : 2022-11-22DOI: 10.17073/0368-0797-2022-11-824-830
A. Nefedov, T. G. Shkurko, N. Chichenev, N. Kholodova
The paper considers results of the analysis of operability of the transporting equipment at agglomeration shops of the Ural metallurgical enterprises. It was established that during long-term operation of the hopper car for transportation of hot agglomerate, dust settles on its walls, growths of accumulated dust are formed, and the effect of vaulting occurs. Due to compaction and increase in dust layer, useful volume of the hopper car decreases which in turn leads to the need to carry out dangerous work to clean the dust directly inside the hopper car. Manual labor is used for this purpose. Such works are very dangerous for human health due to high dust content and high injury risk. In order to eliminate the problem of vaulting and accumulation of dust on the car walls, it is proposed to use the installation of two vibrating devices of the “False wall” type together with a vibrating neck (vibrating beam). The vibrating element of the device is a plate that is mounted on the inner wall on flexible suspensions (round link chain). Rubber shock absorbers are installed between the plate and the hopper wall, which are used as rubber-fabric conveyor belt. A vibrator is mounted to the plate through the support post, and the transmission of vibrations to the agglomerate is carried out using a vibrating hump, which is welded to the plate (false wall). Introduction of the designed device ensures reduction of unplanned downtime of the hopper cars team and rejection of hazardous to human health work related to the bunkers cleaning. The economic calculation confirms feasibility of the ongoing measures for reengineering of hopper cars in the conditions of agglomerate production at metallurgical enterprises.
{"title":"Modernization of hopper car for transportation of agglomerate and other materials","authors":"A. Nefedov, T. G. Shkurko, N. Chichenev, N. Kholodova","doi":"10.17073/0368-0797-2022-11-824-830","DOIUrl":"https://doi.org/10.17073/0368-0797-2022-11-824-830","url":null,"abstract":"The paper considers results of the analysis of operability of the transporting equipment at agglomeration shops of the Ural metallurgical enterprises. It was established that during long-term operation of the hopper car for transportation of hot agglomerate, dust settles on its walls, growths of accumulated dust are formed, and the effect of vaulting occurs. Due to compaction and increase in dust layer, useful volume of the hopper car decreases which in turn leads to the need to carry out dangerous work to clean the dust directly inside the hopper car. Manual labor is used for this purpose. Such works are very dangerous for human health due to high dust content and high injury risk. In order to eliminate the problem of vaulting and accumulation of dust on the car walls, it is proposed to use the installation of two vibrating devices of the “False wall” type together with a vibrating neck (vibrating beam). The vibrating element of the device is a plate that is mounted on the inner wall on flexible suspensions (round link chain). Rubber shock absorbers are installed between the plate and the hopper wall, which are used as rubber-fabric conveyor belt. A vibrator is mounted to the plate through the support post, and the transmission of vibrations to the agglomerate is carried out using a vibrating hump, which is welded to the plate (false wall). Introduction of the designed device ensures reduction of unplanned downtime of the hopper cars team and rejection of hazardous to human health work related to the bunkers cleaning. The economic calculation confirms feasibility of the ongoing measures for reengineering of hopper cars in the conditions of agglomerate production at metallurgical enterprises.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"378 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80630294","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 : 2022-11-22DOI: 10.17073/0368-0797-2022-11-786-797
Yu. V. Gamin, A. V. Korotitskii, T. Kin, S. Galkin, S. Kostin, E. O. Tikhomirov
In the article, the tests of the medical alloy Co – 28Cr – 6Mo after homogenization for uniaxial compression at temperatures of 1000, 1100 and 1200 °C and strain rates of 1, 10, and 50 s–1 were carried out using the Gleeble System 3800. The stress-strain curves describing the alloy deformation behavior were obtained. The calculations of hot deformation parameters (activation energy, Zener-Hollomon parameter) were performed using three models (power-law, exponential, and hyperbolic sine function) describing the flow stress. The highest degree of convergence was shown by the calculation results based on the power function and the hyperbolic sine function. These models can be used to accurately calculate the flow stress at given temperature and strain rate parameters, or to simulate the deformation process. Also, based on processing maps, the authors developed the deformation-speed modes of hot deformation of the Co – 28Cr – 6Mo alloy. It will make it possible to choose the optimal rolling modes in the future. According to the data obtained, favorable temperature-speed conditions for hot deformation are shifted as deformation accumulates to the region of high temperatures and low strain rates. At the same time, the extremely unfavorable zone with negative values of the ξ-criterion, which appears at e = 0.3 – 0.4, continues to grow quite significantly with an increase in the deformation effect. Hot deformation of the Co – 28Cr – 6Mo alloy at low compression ratios (e < 0.2) is more expedient to perform at temperatures above 1150 °C and strain rates of at least 20 s–1. With an increase in deformation degree, it is necessary to choose lower strain rates (1 – 5 s–1) and higher deformation temperature.
{"title":"Development of temperature-speed modes of hot deformation of Co – 28Cr – 6Mo alloy based on processing maps","authors":"Yu. V. Gamin, A. V. Korotitskii, T. Kin, S. Galkin, S. Kostin, E. O. Tikhomirov","doi":"10.17073/0368-0797-2022-11-786-797","DOIUrl":"https://doi.org/10.17073/0368-0797-2022-11-786-797","url":null,"abstract":"In the article, the tests of the medical alloy Co – 28Cr – 6Mo after homogenization for uniaxial compression at temperatures of 1000, 1100 and 1200 °C and strain rates of 1, 10, and 50 s–1 were carried out using the Gleeble System 3800. The stress-strain curves describing the alloy deformation behavior were obtained. The calculations of hot deformation parameters (activation energy, Zener-Hollomon parameter) were performed using three models (power-law, exponential, and hyperbolic sine function) describing the flow stress. The highest degree of convergence was shown by the calculation results based on the power function and the hyperbolic sine function. These models can be used to accurately calculate the flow stress at given temperature and strain rate parameters, or to simulate the deformation process. Also, based on processing maps, the authors developed the deformation-speed modes of hot deformation of the Co – 28Cr – 6Mo alloy. It will make it possible to choose the optimal rolling modes in the future. According to the data obtained, favorable temperature-speed conditions for hot deformation are shifted as deformation accumulates to the region of high temperatures and low strain rates. At the same time, the extremely unfavorable zone with negative values of the ξ-criterion, which appears at e = 0.3 – 0.4, continues to grow quite significantly with an increase in the deformation effect. Hot deformation of the Co – 28Cr – 6Mo alloy at low compression ratios (e < 0.2) is more expedient to perform at temperatures above 1150 °C and strain rates of at least 20 s–1. With an increase in deformation degree, it is necessary to choose lower strain rates (1 – 5 s–1) and higher deformation temperature.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86250890","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 : 2022-10-30DOI: 10.17073/0368-0797-2022-10-683-692
V. Gromov, S. Konovalov, O. Peregudov, M. Efimov, Yu. A. Shlyarova
The authors made a brief review of recent publications by foreign and domestic researchers on the structure, phase composition, and properties of films and coatings of five-component high-entropy alloys (HEA) on various substrates and modification of the HEA surface by various types of processing. The main methods of applying films and coatings are considered: magnetron sputtering, thermal sputtering, laser sputtering, and electrodeposition. Particular attention is paid to the deposition of coatings on stainless steels and titanium alloys. The positive change in the tribological, strength properties, and corrosion resistance of film coatings in a wide temperature range is analyzed and possible causes of the observed effects are discussed. The role of solid solution strengthening, formation of fine-grained structure, and the formation of oxide layers enriched with one of the HEA components were taken into account. The authors identified new methods for applying coatings from HEA and subsequent processing. Using Nb and Ti doping as an example, their role in increasing microhardness, wear resistance, and reducing the friction coefficient in coatings were revealed. Electrolytic polishing, electroerosive machining, mechanical polishing and their combination are considered among the methods of HEA surface treatment. A number of works propose a method of powder borating to increase the surface strength and wear resistance of HEAs. The paper considers analysis of works on electron-beam processing as one of the promising and high efficient methods of HEA surface hardening.
{"title":"Coatings from high-entropy alloys: State and prospects","authors":"V. Gromov, S. Konovalov, O. Peregudov, M. Efimov, Yu. A. Shlyarova","doi":"10.17073/0368-0797-2022-10-683-692","DOIUrl":"https://doi.org/10.17073/0368-0797-2022-10-683-692","url":null,"abstract":"The authors made a brief review of recent publications by foreign and domestic researchers on the structure, phase composition, and properties of films and coatings of five-component high-entropy alloys (HEA) on various substrates and modification of the HEA surface by various types of processing. The main methods of applying films and coatings are considered: magnetron sputtering, thermal sputtering, laser sputtering, and electrodeposition. Particular attention is paid to the deposition of coatings on stainless steels and titanium alloys. The positive change in the tribological, strength properties, and corrosion resistance of film coatings in a wide temperature range is analyzed and possible causes of the observed effects are discussed. The role of solid solution strengthening, formation of fine-grained structure, and the formation of oxide layers enriched with one of the HEA components were taken into account. The authors identified new methods for applying coatings from HEA and subsequent processing. Using Nb and Ti doping as an example, their role in increasing microhardness, wear resistance, and reducing the friction coefficient in coatings were revealed. Electrolytic polishing, electroerosive machining, mechanical polishing and their combination are considered among the methods of HEA surface treatment. A number of works propose a method of powder borating to increase the surface strength and wear resistance of HEAs. The paper considers analysis of works on electron-beam processing as one of the promising and high efficient methods of HEA surface hardening.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87760226","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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