Pub Date : 2021-07-08DOI: 10.15407/steelcast2021.02.052
L. Solonenko, S. Repyakh
The aim of the study is to elucidate the mechanism of the occurrence of internal cracks in casting molds and rods, structured by the process of steam-microwave hardening (SMH), with sand clad with water glass. The studies used quartz sand of grade 1K 1 O 1 02, which was clad with soda sodium water glass with a silicate modulus of 2.9 and a specific density of 1440 kg/m 3 at 20 ° C. Dilatometric measurements were carried out in a chamber of a specially adapted microwave oven with a magnetron power of 700 W and a frequency of 2.45 GHz. The linear change in the height of the sand in the container was recorded by video recording of the readings of the dial indicator in time. The sands were tested in both microwave and steam-microwave radiation with the previous sifting of dry clad sand through a sieve with a mesh of 0.4 mm and 0.63 mm. The article presents the results of dilatometric studies of changes in the size of samples from pure sand and sand clad with liquid glass, during their processing by microwave radiation in air and in a water vapor environment. It is shown that the reason for the appearance of internal cracks in casting molds and cores, which are made by the SMH-process, is the temporary cessation of microwave action on the mixture during its structuring. As a result, due to the difference in the nature and magnitude of the change in the size of the structured and unstructured mixture in the flask (core box), a layer with a weak mechanical bond between adjacent grains of sand appears at the structuring front, and, as a result, an internal crack. The scientific novelty of the work lies in the elucidation of the causes and mechanism of the occurrence of internal cracks in casting molds and rods, structured by the SMH-process with sand clad with liquid glass.
{"title":"Internal cracks in rods, structured in a steam microwave environment","authors":"L. Solonenko, S. Repyakh","doi":"10.15407/steelcast2021.02.052","DOIUrl":"https://doi.org/10.15407/steelcast2021.02.052","url":null,"abstract":"The aim of the study is to elucidate the mechanism of the occurrence of internal cracks in casting molds and rods, structured by the process of steam-microwave hardening (SMH), with sand clad with water glass. The studies used quartz sand of grade 1K 1 O 1 02, which was clad with soda sodium water glass with a silicate modulus of 2.9 and a specific density of 1440 kg/m 3 at 20 ° C. Dilatometric measurements were carried out in a chamber of a specially adapted microwave oven with a magnetron power of 700 W and a frequency of 2.45 GHz. The linear change in the height of the sand in the container was recorded by video recording of the readings of the dial indicator in time. The sands were tested in both microwave and steam-microwave radiation with the previous sifting of dry clad sand through a sieve with a mesh of 0.4 mm and 0.63 mm. The article presents the results of dilatometric studies of changes in the size of samples from pure sand and sand clad with liquid glass, during their processing by microwave radiation in air and in a water vapor environment. It is shown that the reason for the appearance of internal cracks in casting molds and cores, which are made by the SMH-process, is the temporary cessation of microwave action on the mixture during its structuring. As a result, due to the difference in the nature and magnitude of the change in the size of the structured and unstructured mixture in the flask (core box), a layer with a weak mechanical bond between adjacent grains of sand appears at the structuring front, and, as a result, an internal crack. The scientific novelty of the work lies in the elucidation of the causes and mechanism of the occurrence of internal cracks in casting molds and rods, structured by the SMH-process with sand clad with liquid glass.","PeriodicalId":33778,"journal":{"name":"Metall i lit''e Ukrainy","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44282214","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 : 2021-07-08DOI: 10.15407/steelcast2021.02.101
O. Verzilov, M. Voron, A. Semenko, V. Shemet
{"title":"The current state and the prospects for the development of high-plasticity ultrastrong Fe-Mn-Al-C steels","authors":"O. Verzilov, M. Voron, A. Semenko, V. Shemet","doi":"10.15407/steelcast2021.02.101","DOIUrl":"https://doi.org/10.15407/steelcast2021.02.101","url":null,"abstract":"","PeriodicalId":33778,"journal":{"name":"Metall i lit''e Ukrainy","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44251269","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 : 2021-07-08DOI: 10.15407/steelcast2021.02.090
K. Baiul, I. Muraviova, S. Vashchenko, O. Khudyakov, N. Solodka
{"title":"General classification and system approach to the development of roll press structures","authors":"K. Baiul, I. Muraviova, S. Vashchenko, O. Khudyakov, N. Solodka","doi":"10.15407/steelcast2021.02.090","DOIUrl":"https://doi.org/10.15407/steelcast2021.02.090","url":null,"abstract":"","PeriodicalId":33778,"journal":{"name":"Metall i lit''e Ukrainy","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43934572","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 : 2021-07-08DOI: 10.15407/steelcast2021.02.031
S.M. Pisarskyi, O. Smirnov
{"title":"Analysis and development of modern concepts on the rhomboidity formation nature for continuously cast billets. Part 1","authors":"S.M. Pisarskyi, O. Smirnov","doi":"10.15407/steelcast2021.02.031","DOIUrl":"https://doi.org/10.15407/steelcast2021.02.031","url":null,"abstract":"","PeriodicalId":33778,"journal":{"name":"Metall i lit''e Ukrainy","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44616042","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 : 2021-01-01DOI: 10.15407/STEELCAST2021.01.032
M. Yamshynskyi, Georgy Fedorov
The analyzes of operating conditions of high-temperature parts of fuel-burning devices of boiler units at thermoelectric power stations (TPS) has revealed that their operating temperature reaches 1100–1250 ° C. Since the nozzles of such devices are subjected to intense abrasive actions of coal dust and other fuel components and wear out quickly as a result of erosion processes, then Cr-Al steels with an optimal carbon content can also be used. From the economic point of view, it should be noted that nickel, the content of which in some types of steel reaches 20 %, belongs to expensive and scarce metals. Thus, its use in such quantities for alloying heat-resistant steels is unjustified and impractical, and it becomes possible to replace expensive heat-resistant chromium-nickel steels with cheap casting materials, for example, iron-based alloys with a high chromium content. The choice of an alloy with high oxidation resistance is necessary but insufficient criterion to ensure the reliability and durability of its operation. This is due to the fact that in the process of operation, the products are subjected to periodic heating and cool-ing, that means thermal cycles. In this case, an unequal temperature field arises in the volume of the metal, which contributes to the accumulation of thermal tension. Such tensions can exceed the permissible norms under these conditions, as a result plastic deformation develops in the metal, which subsequently leads to its destruction. To achieve the goal, the work investigated the effect of alloying elements of chromium and aluminum on the heat resistance of iron-based alloys in superheated air with the addition of water vapor and carbon dioxide. The main chemical element in steels of this class is carbon, which has a negative effect on oxidation resistance; therefore, this fact must be taken into account when choosing a heat-resistant steel to manufacture products operating at high temperatures and aggressive environments. A decrease in the rate of oxidation of alloys at high temperatures is achieved due to the formation of a dense protective oxide layer on their surfaces, in which the processes of diffusion transfer of metal and oxygen ions are significantly complicated. This is obtained by adding appropriate amounts of chromium and aluminum to the steel. When the content of aluminum is more than 4 %, the rate of its burnout is practically constant, and the average content of aluminum in steel at any moment of the test time submits to linear relationship.
{"title":"Oxidation resistance of aluminum chromium steels in agressive environments","authors":"M. Yamshynskyi, Georgy Fedorov","doi":"10.15407/STEELCAST2021.01.032","DOIUrl":"https://doi.org/10.15407/STEELCAST2021.01.032","url":null,"abstract":"The analyzes of operating conditions of high-temperature parts of fuel-burning devices of boiler units at thermoelectric power stations (TPS) has revealed that their operating temperature reaches 1100–1250 ° C. Since the nozzles of such devices are subjected to intense abrasive actions of coal dust and other fuel components and wear out quickly as a result of erosion processes, then Cr-Al steels with an optimal carbon content can also be used. From the economic point of view, it should be noted that nickel, the content of which in some types of steel reaches 20 %, belongs to expensive and scarce metals. Thus, its use in such quantities for alloying heat-resistant steels is unjustified and impractical, and it becomes possible to replace expensive heat-resistant chromium-nickel steels with cheap casting materials, for example, iron-based alloys with a high chromium content. The choice of an alloy with high oxidation resistance is necessary but insufficient criterion to ensure the reliability and durability of its operation. This is due to the fact that in the process of operation, the products are subjected to periodic heating and cool-ing, that means thermal cycles. In this case, an unequal temperature field arises in the volume of the metal, which contributes to the accumulation of thermal tension. Such tensions can exceed the permissible norms under these conditions, as a result plastic deformation develops in the metal, which subsequently leads to its destruction. To achieve the goal, the work investigated the effect of alloying elements of chromium and aluminum on the heat resistance of iron-based alloys in superheated air with the addition of water vapor and carbon dioxide. The main chemical element in steels of this class is carbon, which has a negative effect on oxidation resistance; therefore, this fact must be taken into account when choosing a heat-resistant steel to manufacture products operating at high temperatures and aggressive environments. A decrease in the rate of oxidation of alloys at high temperatures is achieved due to the formation of a dense protective oxide layer on their surfaces, in which the processes of diffusion transfer of metal and oxygen ions are significantly complicated. This is obtained by adding appropriate amounts of chromium and aluminum to the steel. When the content of aluminum is more than 4 %, the rate of its burnout is practically constant, and the average content of aluminum in steel at any moment of the test time submits to linear relationship.","PeriodicalId":33778,"journal":{"name":"Metall i lit''e Ukrainy","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41860449","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 : 2021-01-01DOI: 10.15407/STEELCAST2021.01.026
Yu. F. Ternovyi, A. Prigunova, V. Panova
of the technological process for the production of metal products using the powder metallurgy method. Among the wide variety of methods for making powders, in terms of efficiency and productivity, the spraying of melts with high-pressure water is favorably distinguished, in which the geometric shape and microstructure of particles significantly depend on the cooling rate, which is associated with the peculiarities of heat transfer in the melt drop – water – gas phase system. However, experimental confirmation of one or another mode of heat transfer is not possible, which is associated with the small size of particles, the number of which in 1 cm 3 of the spray zone is about 10 7 . The influence of the thermal physics of the sputtering process on the solidification rate of metal droplets is analyzed. Based on the analysis of the known regularities and phenomena of heat and mass transfer, the heat transfer coef-ficients, the heat flux density for various heat transfer modes, as well as the contribution of the conductive, convective and radiation components of heat transfer are estimated. It is shown that the fraction of heat transfer by radiation is no more than 0.1 %. It has been theoretically proven that droplets are cooled in the bubble mode of water boiling. For tool steel, the particle cooling rate calculated on the basis of the heat transfer coefficient in the developed bubble mode is about 10 6 K/s. Such a cooling rate during bubble or pseudobubble boiling is provided when the resulting vapor film is "torn off" by the water flow, simulating "pseudobubble" cooling. The formation of a cellular structure of powders, which is observed in practice during spraying with water under pressure, confirms the correctness of the theoretical calculations. The results of the work can be used to substantiate the thermal regimes for obtaining powders with various structures, including amorphous ones.
介绍了采用粉末冶金法生产金属制品的工艺流程。在各种各样的粉末制造方法中，就效率和生产率而言，高压水喷射熔体是很好的区分，其中颗粒的几何形状和微观结构显著依赖于冷却速度，这与熔体滴-水-气相系统中传热的特性有关。然而，实验无法证实一种或另一种传热模式，这与颗粒尺寸小有关，在1 cm 3的喷雾区中颗粒的数量约为10 7。分析了溅射过程的热物理特性对金属液滴凝固速率的影响。在分析已知的传热传质规律和现象的基础上，估计了各种传热方式的传热系数、热流密度以及传热中传导、对流和辐射分量的贡献。结果表明，辐射传热的比例不大于0.1%。从理论上证明了液滴是在水沸腾的气泡模式下冷却的。对于工具钢，根据发达气泡模式下的传热系数计算出的颗粒冷却速率约为10.6 K/s。当产生的蒸汽膜被水流“撕裂”，模拟“假气泡”冷却时，在气泡或假气泡沸腾期间提供这样的冷却速率。在加压喷水过程中观察到粉末的胞状结构形成，证实了理论计算的正确性。这项工作的结果可以用来证实获得具有各种结构的粉末的热状态，包括非晶结构。
{"title":"Forced heat exchange and cooling rate of drops at producing metal powders by melt water atomizatio","authors":"Yu. F. Ternovyi, A. Prigunova, V. Panova","doi":"10.15407/STEELCAST2021.01.026","DOIUrl":"https://doi.org/10.15407/STEELCAST2021.01.026","url":null,"abstract":"of the technological process for the production of metal products using the powder metallurgy method. Among the wide variety of methods for making powders, in terms of efficiency and productivity, the spraying of melts with high-pressure water is favorably distinguished, in which the geometric shape and microstructure of particles significantly depend on the cooling rate, which is associated with the peculiarities of heat transfer in the melt drop – water – gas phase system. However, experimental confirmation of one or another mode of heat transfer is not possible, which is associated with the small size of particles, the number of which in 1 cm 3 of the spray zone is about 10 7 . The influence of the thermal physics of the sputtering process on the solidification rate of metal droplets is analyzed. Based on the analysis of the known regularities and phenomena of heat and mass transfer, the heat transfer coef-ficients, the heat flux density for various heat transfer modes, as well as the contribution of the conductive, convective and radiation components of heat transfer are estimated. It is shown that the fraction of heat transfer by radiation is no more than 0.1 %. It has been theoretically proven that droplets are cooled in the bubble mode of water boiling. For tool steel, the particle cooling rate calculated on the basis of the heat transfer coefficient in the developed bubble mode is about 10 6 K/s. Such a cooling rate during bubble or pseudobubble boiling is provided when the resulting vapor film is \"torn off\" by the water flow, simulating \"pseudobubble\" cooling. The formation of a cellular structure of powders, which is observed in practice during spraying with water under pressure, confirms the correctness of the theoretical calculations. The results of the work can be used to substantiate the thermal regimes for obtaining powders with various structures, including amorphous ones.","PeriodicalId":33778,"journal":{"name":"Metall i lit''e Ukrainy","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45292300","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 : 2021-01-01DOI: 10.15407/STEELCAST2021.01.054
V. Gnatush, M. Voron
The analysis of the scientific researches devoted to questions of influence of the content of hydrogen and oxide inclusions in aluminum alloys in the context of these impurities interaction of with various components of material is presented. Based on the published results of experiments in scientific works, aluminum alloys depending on their hydrogen content can be divided into the following four groups: aluminum alloys with nominal hydrogen content; aluminum alloys containing hydride-forming additives; aluminum alloys with high hydrogen content; aluminum alloys with excess hydrogen content (gas). Information on single- and multistage methods of aluminum melt refining, as well as classification of quality control methods for aluminum alloy refining is presented. Some features of properties of aluminum alloys which contain hydride-forming additives are con-sidered. The results of the study of high hydrogen content on the mechanical characteristics of aluminum alloys are traced. Features of technologies of creation of aluminum alloys with ultrahigh content of gases (foam aluminum) are considered. Information on the content of non-metallic inclusions in aluminum and aluminum alloys and methods for determining their content in the melt is presented. Based on the review and analysis, the need for comprehensive studies of the system hydrogen – oxide – alloying/modifying metals in aluminum alloys is shown to clarify the mechanisms of physicochemical and metal- lophysical processes that are realized in the crystallization of aluminum melts. There is a need to use experimental planning to build mathematical models of the relationship between hydrogen/oxide content, process parameters and properties of samples and products made of aluminum alloys. Aluminum alloys, hydrogen, oxides, refining, modification, non-metallic inclusions.
{"title":"Current aspects of hydrogen and oxygen content in aluminum alloys","authors":"V. Gnatush, M. Voron","doi":"10.15407/STEELCAST2021.01.054","DOIUrl":"https://doi.org/10.15407/STEELCAST2021.01.054","url":null,"abstract":"The analysis of the scientific researches devoted to questions of influence of the content of hydrogen and oxide inclusions in aluminum alloys in the context of these impurities interaction of with various components of material is presented. Based on the published results of experiments in scientific works, aluminum alloys depending on their hydrogen content can be divided into the following four groups: aluminum alloys with nominal hydrogen content; aluminum alloys containing hydride-forming additives; aluminum alloys with high hydrogen content; aluminum alloys with excess hydrogen content (gas). Information on single- and multistage methods of aluminum melt refining, as well as classification of quality control methods for aluminum alloy refining is presented. Some features of properties of aluminum alloys which contain hydride-forming additives are con-sidered. The results of the study of high hydrogen content on the mechanical characteristics of aluminum alloys are traced. Features of technologies of creation of aluminum alloys with ultrahigh content of gases (foam aluminum) are considered. Information on the content of non-metallic inclusions in aluminum and aluminum alloys and methods for determining their content in the melt is presented. Based on the review and analysis, the need for comprehensive studies of the system hydrogen – oxide – alloying/modifying metals in aluminum alloys is shown to clarify the mechanisms of physicochemical and metal- lophysical processes that are realized in the crystallization of aluminum melts. There is a need to use experimental planning to build mathematical models of the relationship between hydrogen/oxide content, process parameters and properties of samples and products made of aluminum alloys. Aluminum alloys, hydrogen, oxides, refining, modification, non-metallic inclusions.","PeriodicalId":33778,"journal":{"name":"Metall i lit''e Ukrainy","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47993808","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 : 2021-01-01DOI: 10.15407/steelcast2021.01.038
Solonenko L.I., Repyakh S.I.
{"title":"Manufacture of foundry forms by steam-microwave hardening by models from frozen sand-water mixtures","authors":"Solonenko L.I., Repyakh S.I.","doi":"10.15407/steelcast2021.01.038","DOIUrl":"https://doi.org/10.15407/steelcast2021.01.038","url":null,"abstract":"","PeriodicalId":33778,"journal":{"name":"Metall i lit''e Ukrainy","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67014581","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 : 2021-01-01DOI: 10.15407/STEELCAST2021.01.081
O. Babachenko, G. Kononenko, R. Podolskyi, O. Safronova
The mechanical properties of railroad rails depend on the chemical composition, the elaboration of the cast structure by metal pressure treatment, as well as the heat treatment of the finished rails. The aim of this work is to study the effect of hot plastic deformation (hereinafter HPD) and heat treatment (hereinafter HT) on the change in the structure of the cast state in relation to its initial chemical heterogeneity. The general theoretical conclusions of this work were obtained on the basis of an analysis of literary sources, as well as many years of research on wheel products. These results complement the existing understanding of structural heredity in metals and alloys. The chemical composition of experimental steels for railroad rails has been developed and ingots weighing up to 10 kg have been smelted under laboratory conditions. The study of the micro- structure was carried out and the hardness of the experimental steel was determined on samples of 70x70x80 mm in size, cut from ingots of laboratory rail heats. It was processed in laboratory conditions in two modes: 1 – HPD with a sediment of 50 % after heating to 1250 ± 10 ° С; 2 – normalization (austenitization at 900 ± 10 ° C, air cooling at a rate of 5.1 ° C/s) after HPD. In the study of the cast state of experimental rail steels (RST), it was found that it is austenite dendrites enriched with impurity elements. The effect of hot plastic deformation and heat treatment on the structure and properties of a cast test steel for railroad rails has been studied. The positive effect of deformation and subsequent heat treatment on the mechanical properties of experimental steels was established: after hot plastic deformation, in comparison with the cast state, the increase in hardness was ≈ 14.1 %; after hot plastic deformation with subsequent heat treatment, the increase in hardness was ≈ 39.4 %. The influence of the primary dendritic structure of the investigated steel on its final pearlite structure in the cast state has been established.
{"title":"Investigation of the microstructure and hardness of experimental rail steels in the cast state, after hot plastic deformation and heat treatment","authors":"O. Babachenko, G. Kononenko, R. Podolskyi, O. Safronova","doi":"10.15407/STEELCAST2021.01.081","DOIUrl":"https://doi.org/10.15407/STEELCAST2021.01.081","url":null,"abstract":"The mechanical properties of railroad rails depend on the chemical composition, the elaboration of the cast structure by metal pressure treatment, as well as the heat treatment of the finished rails. The aim of this work is to study the effect of hot plastic deformation (hereinafter HPD) and heat treatment (hereinafter HT) on the change in the structure of the cast state in relation to its initial chemical heterogeneity. The general theoretical conclusions of this work were obtained on the basis of an analysis of literary sources, as well as many years of research on wheel products. These results complement the existing understanding of structural heredity in metals and alloys. The chemical composition of experimental steels for railroad rails has been developed and ingots weighing up to 10 kg have been smelted under laboratory conditions. The study of the micro- structure was carried out and the hardness of the experimental steel was determined on samples of 70x70x80 mm in size, cut from ingots of laboratory rail heats. It was processed in laboratory conditions in two modes: 1 – HPD with a sediment of 50 % after heating to 1250 ± 10 ° С; 2 – normalization (austenitization at 900 ± 10 ° C, air cooling at a rate of 5.1 ° C/s) after HPD. In the study of the cast state of experimental rail steels (RST), it was found that it is austenite dendrites enriched with impurity elements. The effect of hot plastic deformation and heat treatment on the structure and properties of a cast test steel for railroad rails has been studied. The positive effect of deformation and subsequent heat treatment on the mechanical properties of experimental steels was established: after hot plastic deformation, in comparison with the cast state, the increase in hardness was ≈ 14.1 %; after hot plastic deformation with subsequent heat treatment, the increase in hardness was ≈ 39.4 %. The influence of the primary dendritic structure of the investigated steel on its final pearlite structure in the cast state has been established.","PeriodicalId":33778,"journal":{"name":"Metall i lit''e Ukrainy","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42742899","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 : 2021-01-01DOI: 10.15407/STEELCAST2021.01.020
O. Smirnov, O. Verzilov, A. Kravchenko, Yu.O. Smirnov, A. Semenko, D.I. Hoida
моделювання поведінки розплаву формування застійних зон в однострумковому проміжному ковші умовах металургійного The research presented in this paper is aimed at choosing the optimal geometric shape of the tundish box, which must meet the conditions of work in a single-flow tundish with continuous or semi-continuous casting of high-grade or bloom billets in small metallurgical micro-mills. The experiments based on the establishment of a hydrodynamic pattern of metal leakage in the tundish, performed on a physical cold model, were based on the following options: without tundish box (№ 1), asymmetric tundish box with low side, deployed towards the dispenser glass (№ 2), asymmetric tundish box with a low side, deployed in the direction of the nearest narrow wall (№ 3), asymmetric tundish box without side, also deployed in the direction of a narrow wall (№ 4). The best results were shown by broom tundish box deployed towards the nearest narrow wall. But it should be noted that the impact of convec-tive and circulating flows on the lining in this area needs further research. An volume tundish tundish, beaker. was first the narrow tundish. tundish seconds, tundish box design 2 seconds; 3 seconds; a stagnant the tundish box and the tundish nozzle 35–60
моделювання поведінки розплаву формування застійних зон однострумковому проміжному ковші умовах металургійного本文的研究目的是选择中间包箱的最佳几何形状，该形状必须满足小型冶金微轧机连续或半连续铸造高档或坯坯的单流中间包的工作条件。在建立中间包金属泄漏流体动力模式的基础上，在物理冷模型上进行的实验基于以下选项:无中间包箱(№1)，低边的不对称中间包箱，向分配器玻璃方向部署(№2)，低边的不对称中间包箱，向最近的窄壁方向部署(№3)，无边的不对称中间包箱，也向窄壁方向部署(№4)。向最近的窄壁部署的扫帚中间包箱显示出最好的效果。但需要注意的是，对流流动和循环流动对该地区衬板的影响还需要进一步研究。中间包，中间包，烧杯。首先是狭窄的中间包。中间包秒，中间包箱设计秒2;3秒;中间包箱与中间包喷嘴之间有35-60的停滞
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