Pub Date : 2024-02-25DOI: 10.17073/0368-0797-2024-1-89-105
M. Y. Ryabchikov, E. Ryabchikova, V. S. Novak, A. E. Klimenko
The goals of the work were to search and systematize the speed limits of the steel strip during hot-dip galvanizing, associated with the threat of product defects. Since speed can be combined with many other factors, this paper provides an overview of the known causes of common defects. The causes were grouped taking into account the operations of individual sections of continuous hot-dip galvanizing units. To determine the circumstances in which defects occur, a method was used that involved step-by-step stratification of retrospective data and comparison of the distribution density of influencing factors for defective and non-defective products. The method was applied in the analysis of the data on defects at the MMK Metallurgy plant in Turkey, obtained in 2020–2021. Twenty-one types of acceptable and unacceptable defects that occur during galvanizing of DX51D steel were selected for analysis. Twenty-two technological parameters were taken as factors, including the strip speed. For each selected type of the defects, a set of influencing factors is determined, and for some types of defects, the alleged causes of their occurrence are indicated. It is shown that the relationship observed for many types of defects with the strip speed can actually be caused by other factors. We determined the types of defects, the probability of which increases with an increase in the speed or the level of its change. The paper proposes measures aimed at preventing the increase in the proportion of defective products along with the performance gain.
{"title":"Investigation of performance limitations in continuous hot-dip galvanizing units associated with product defects","authors":"M. Y. Ryabchikov, E. Ryabchikova, V. S. Novak, A. E. Klimenko","doi":"10.17073/0368-0797-2024-1-89-105","DOIUrl":"https://doi.org/10.17073/0368-0797-2024-1-89-105","url":null,"abstract":"The goals of the work were to search and systematize the speed limits of the steel strip during hot-dip galvanizing, associated with the threat of product defects. Since speed can be combined with many other factors, this paper provides an overview of the known causes of common defects. The causes were grouped taking into account the operations of individual sections of continuous hot-dip galvanizing units. To determine the circumstances in which defects occur, a method was used that involved step-by-step stratification of retrospective data and comparison of the distribution density of influencing factors for defective and non-defective products. The method was applied in the analysis of the data on defects at the MMK Metallurgy plant in Turkey, obtained in 2020–2021. Twenty-one types of acceptable and unacceptable defects that occur during galvanizing of DX51D steel were selected for analysis. Twenty-two technological parameters were taken as factors, including the strip speed. For each selected type of the defects, a set of influencing factors is determined, and for some types of defects, the alleged causes of their occurrence are indicated. It is shown that the relationship observed for many types of defects with the strip speed can actually be caused by other factors. We determined the types of defects, the probability of which increases with an increase in the speed or the level of its change. The paper proposes measures aimed at preventing the increase in the proportion of defective products along with the performance gain.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140432670","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 : 2024-02-25DOI: 10.17073/0368-0797-2024-1-83-88
M. Salynova, T. Uglunts, O. Tolochko
The work is devoted to the study of the effect of microalloying with yttrium (Y) additives to improve the corrosion resistance of Incoloy 825 superalloy. The influence of Y on microstructure was evaluated by metallographic methods using optical and scanning electron microscopes, resistance to pitting and intergranular corrosion was evaluated by electrochemical and chemical methods of analysis. The paper describes changes in the structure, phase composition and hardness of cast samples with yttrium content of 0, 0.01, 0.05 and 0.1 wt. %. The obtained data correlate with the results of thermodynamic calculations of phase formation during crystallization. The influence of additions on the structure after strain hardening was investigated. Small addition (up to 0.01 wt. %) promotes increase of mobility of recrystallized grain boundaries. With increasing Y amount, the grain size decreases and hardness increases. It is shown that the greatest deoxidizing ability is observed at small additions of Y in the amount up to 0.01 wt. %, while the total amount of dissolved [O] decreased five times. Increasing the Y content reduces the ability to remove heavy inclusions from the melt, resulting in an increase in the proportion of oxide inclusions. The effect of additives on nitrogen [N] was not observed, and the volume fraction of nitride inclusions did not change, but the size of nitride inclusions decreased and the character of their distribution changed to uniform than in the alloy without Y. The results of pitting and intergranular fracture resistance tests showed that Y is an element that can be used to improve the corrosion properties of Incoloy 825 alloy. The best combination of resistance to the two types of corrosion was observed for the 0.01 wt. % Y sample.
这项研究专门探讨了添加钇（Y）添加剂的微合金化对提高 Incoloy 825 超级合金耐腐蚀性的影响。通过使用光学显微镜和扫描电子显微镜的金相方法评估了钇对微观结构的影响，并通过电化学和化学分析方法评估了抗点蚀和晶间腐蚀的能力。论文描述了钇含量为 0、0.01、0.05 和 0.1 wt. % 的铸件样品在结构、相组成和硬度方面的变化。获得的数据与结晶过程中相形成的热力学计算结果相关。研究了添加量对应变硬化后结构的影响。少量添加（最多 0.01 wt.%）可促进再结晶晶界流动性的增加。随着 Y 量的增加，晶粒尺寸减小，硬度增加。研究表明，Y 的少量添加（最高为 0.01 wt.%）时脱氧能力最强，而溶解的 [O] 总量则减少了五倍。增加 Y 的含量会降低从熔体中去除重夹杂物的能力，导致氧化物夹杂物的比例增加。添加剂对氮[N]的影响没有观察到，氮化物夹杂物的体积分数也没有变化，但氮化物夹杂物的尺寸减小了，其分布特征也比不含 Y 的合金变为均匀。0.01 wt. % Y 样品对这两种腐蚀的抗性组合最佳。
{"title":"Effect of yttrium additions on microstructure and corrosion resistance of Incoloy 825 alloy","authors":"M. Salynova, T. Uglunts, O. Tolochko","doi":"10.17073/0368-0797-2024-1-83-88","DOIUrl":"https://doi.org/10.17073/0368-0797-2024-1-83-88","url":null,"abstract":"The work is devoted to the study of the effect of microalloying with yttrium (Y) additives to improve the corrosion resistance of Incoloy 825 superalloy. The influence of Y on microstructure was evaluated by metallographic methods using optical and scanning electron microscopes, resistance to pitting and intergranular corrosion was evaluated by electrochemical and chemical methods of analysis. The paper describes changes in the structure, phase composition and hardness of cast samples with yttrium content of 0, 0.01, 0.05 and 0.1 wt. %. The obtained data correlate with the results of thermodynamic calculations of phase formation during crystallization. The influence of additions on the structure after strain hardening was investigated. Small addition (up to 0.01 wt. %) promotes increase of mobility of recrystallized grain boundaries. With increasing Y amount, the grain size decreases and hardness increases. It is shown that the greatest deoxidizing ability is observed at small additions of Y in the amount up to 0.01 wt. %, while the total amount of dissolved [O] decreased five times. Increasing the Y content reduces the ability to remove heavy inclusions from the melt, resulting in an increase in the proportion of oxide inclusions. The effect of additives on nitrogen [N] was not observed, and the volume fraction of nitride inclusions did not change, but the size of nitride inclusions decreased and the character of their distribution changed to uniform than in the alloy without Y. The results of pitting and intergranular fracture resistance tests showed that Y is an element that can be used to improve the corrosion properties of Incoloy 825 alloy. The best combination of resistance to the two types of corrosion was observed for the 0.01 wt. % Y sample.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"25 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140432085","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 : 2024-02-25DOI: 10.17073/0368-0797-2024-1-73-75
G. Adilov, N. T. Kareva, V. Roshchin
To evaluate the phase and structural components of grinding media made of cast iron with a high content of copper and silicon obtained by extracting iron from copper-smelting slags, phase equilibria in the iron – carbon system were calculated with the addition of copper and silicon in various concentrations. The calculation was carried out using the ThermoCalc software package with construction of phase diagrams by the Calphad method. At the same time, temperatures of the beginning of phase transformations were estimated taking into account the presence of all thermodynamically possible phases in the system at various combinations of copper and silicon concentrations.
{"title":"Influence of copper and silicon on phase transformations in the iron – carbon system","authors":"G. Adilov, N. T. Kareva, V. Roshchin","doi":"10.17073/0368-0797-2024-1-73-75","DOIUrl":"https://doi.org/10.17073/0368-0797-2024-1-73-75","url":null,"abstract":"To evaluate the phase and structural components of grinding media made of cast iron with a high content of copper and silicon obtained by extracting iron from copper-smelting slags, phase equilibria in the iron – carbon system were calculated with the addition of copper and silicon in various concentrations. The calculation was carried out using the ThermoCalc software package with construction of phase diagrams by the Calphad method. At the same time, temperatures of the beginning of phase transformations were estimated taking into account the presence of all thermodynamically possible phases in the system at various combinations of copper and silicon concentrations.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"6 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140432933","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 : 2024-02-25DOI: 10.17073/0368-0797-2024-1-112-120
T. V. Erokhov, I. A. Levitskii, G. S. Podgorodetskii, V. Gorbunov
Organization of technological process and design of a furnace significantly affect the parameters of post-combustion, determining the need to develop a mathematical model of post-combustion zone. Modeling of gas dynamics, chemical reactions, convective diffusion and heat transfer in the gas phase above the melt was carried out in an experimental melter-gasifier furnace at three different values of mass flow rates and two positions of post-combustion tuyeres. Temperature distributions and off-gas components concentrations were obtained. It was found that at the lower position of the tuyere, post-combustion is carried out in the area of reflected jet, stagnant zones are formed around the tuyere and between the reflected jet and the melt surface, which decrease the post-combustion level. At the upper position of the tuyere, post-combustion occurs inside the primary jet, intensive mixing of all components of the furnace atmosphere occurs, post-combustion undergoes more completely, which leads to an increase in the off-gases temperature with an increase in uniformity of temperature fields and concentrations compared with the lower position of the tuyere. At the lower position of the tuyere, the flame zone turns out to be open, its shape significantly depends on the mass flow, and the flame zone volume increases with an increase in the mass flow. At the upper position of the tuyere, the flame zone is closed, with an increase in the mass flow, its shape does not change, but the flame zone volume decreases. For reduction processes in slag melt, the upper position of the tuyere is preferable, while for production of the producer gas at the furnace outlet, position of the tuyere closer to the melt surface is preferable.
{"title":"Mathematical modeling of gas dynamics and off-gas post-combustion above the melt in a melter-gasifier furnace","authors":"T. V. Erokhov, I. A. Levitskii, G. S. Podgorodetskii, V. Gorbunov","doi":"10.17073/0368-0797-2024-1-112-120","DOIUrl":"https://doi.org/10.17073/0368-0797-2024-1-112-120","url":null,"abstract":"Organization of technological process and design of a furnace significantly affect the parameters of post-combustion, determining the need to develop a mathematical model of post-combustion zone. Modeling of gas dynamics, chemical reactions, convective diffusion and heat transfer in the gas phase above the melt was carried out in an experimental melter-gasifier furnace at three different values of mass flow rates and two positions of post-combustion tuyeres. Temperature distributions and off-gas components concentrations were obtained. It was found that at the lower position of the tuyere, post-combustion is carried out in the area of reflected jet, stagnant zones are formed around the tuyere and between the reflected jet and the melt surface, which decrease the post-combustion level. At the upper position of the tuyere, post-combustion occurs inside the primary jet, intensive mixing of all components of the furnace atmosphere occurs, post-combustion undergoes more completely, which leads to an increase in the off-gases temperature with an increase in uniformity of temperature fields and concentrations compared with the lower position of the tuyere. At the lower position of the tuyere, the flame zone turns out to be open, its shape significantly depends on the mass flow, and the flame zone volume increases with an increase in the mass flow. At the upper position of the tuyere, the flame zone is closed, with an increase in the mass flow, its shape does not change, but the flame zone volume decreases. For reduction processes in slag melt, the upper position of the tuyere is preferable, while for production of the producer gas at the furnace outlet, position of the tuyere closer to the melt surface is preferable.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"8 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140433207","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 : 2024-02-25DOI: 10.17073/0368-0797-2024-1-121-131
V. Shper, S. A. Sheremetyeva, V. Smelov, E. I. Khunuzidi
Shewhart control charts (ShCCs) are a powerful and technically simple tool for process variability analysis. However, simultaneously, they cannot be fully algorithmized and require deep process knowledge together with additional data analysis. ShCCs are well known, though, and the number of papers is great, as well as standards on ShCCs work in most countries, there are some serious obstacles for their effective application which are not being discussed in either educational or scientific literature. Just these problems are being considered in this paper. We analyzed two sides of standard assumption about data normality. First, we discuss the widely-spread misconception that measurement data are always distributed according Gauss law. Then, it is shown how the deviation from normality may impact the method of ShCCs’ constructing and interpreting. Using a specific process data, we debate on right and wrong ways to build ShCC. Further, the paper describes two new definitions of assignable causes of variation: not changing (I-type) and changing (X-type) the system. At the end, we discuss how the work with ShCCs should be organized effectively. It is outlined that creating and analyzing ShCCs is always a system question of interaction between the process and the person who tries to improve this process.
{"title":"Shewhart control charts – A simple but not easy tool for data analysis","authors":"V. Shper, S. A. Sheremetyeva, V. Smelov, E. I. Khunuzidi","doi":"10.17073/0368-0797-2024-1-121-131","DOIUrl":"https://doi.org/10.17073/0368-0797-2024-1-121-131","url":null,"abstract":"Shewhart control charts (ShCCs) are a powerful and technically simple tool for process variability analysis. However, simultaneously, they cannot be fully algorithmized and require deep process knowledge together with additional data analysis. ShCCs are well known, though, and the number of papers is great, as well as standards on ShCCs work in most countries, there are some serious obstacles for their effective application which are not being discussed in either educational or scientific literature. Just these problems are being considered in this paper. We analyzed two sides of standard assumption about data normality. First, we discuss the widely-spread misconception that measurement data are always distributed according Gauss law. Then, it is shown how the deviation from normality may impact the method of ShCCs’ constructing and interpreting. Using a specific process data, we debate on right and wrong ways to build ShCC. Further, the paper describes two new definitions of assignable causes of variation: not changing (I-type) and changing (X-type) the system. At the end, we discuss how the work with ShCCs should be organized effectively. It is outlined that creating and analyzing ShCCs is always a system question of interaction between the process and the person who tries to improve this process.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"1 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140432770","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 : 2024-02-24DOI: 10.17073/0368-0797-2024-1-8-18
P. A. Vityaz’, V. G. Zalesskii, A. I. Pokrovskii
A historical overview of the development of iron foundry production in the world is presented. The modern level of the material structure in iron casting has an outstripping growth of ductile cast iron grades. The paper describes the features of iron foundry production in Belarus. Technologies and equipment are significantly inferior to foreign ones in terms of productivity and specific resource costs per unit of product. The specific character of Belarus lies in the still widespread use of cupolas, molds from sand-clay mixtures, predominant use of gray cast iron, and small volumes of ductile cast iron production. The total capacity of all foundries is 557.5 thousand tons of casting per year, but the peculiarity is that only about 250 thousand tons per year are actually produced. Development and implementation of the “Program for the Development of Foundry Industries of the Republic of Belarus for years 2017–2030” made it possible to ensure more efficient operation of the foundry industry in the country. In the near future Belorussian foundry industry will reproduce the global trend for critical casting products: transfer to ductile cast iron instead of gray one and further transition to ausferritic (bainitic) cast iron instead of rolled steel.
{"title":"Features of iron foundry production in Belarus and its prospects","authors":"P. A. Vityaz’, V. G. Zalesskii, A. I. Pokrovskii","doi":"10.17073/0368-0797-2024-1-8-18","DOIUrl":"https://doi.org/10.17073/0368-0797-2024-1-8-18","url":null,"abstract":"A historical overview of the development of iron foundry production in the world is presented. The modern level of the material structure in iron casting has an outstripping growth of ductile cast iron grades. The paper describes the features of iron foundry production in Belarus. Technologies and equipment are significantly inferior to foreign ones in terms of productivity and specific resource costs per unit of product. The specific character of Belarus lies in the still widespread use of cupolas, molds from sand-clay mixtures, predominant use of gray cast iron, and small volumes of ductile cast iron production. The total capacity of all foundries is 557.5 thousand tons of casting per year, but the peculiarity is that only about 250 thousand tons per year are actually produced. Development and implementation of the “Program for the Development of Foundry Industries of the Republic of Belarus for years 2017–2030” made it possible to ensure more efficient operation of the foundry industry in the country. In the near future Belorussian foundry industry will reproduce the global trend for critical casting products: transfer to ductile cast iron instead of gray one and further transition to ausferritic (bainitic) cast iron instead of rolled steel.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"68 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140433991","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 : 2024-02-24DOI: 10.17073/0368-0797-2024-1-19-26
V. M. Pavlovets
The substantiated problem of improving the structural properties of agglomerated metallurgical raw materials is associated with the formation of a favorable pore structure in iron ore pellets. The author analyzed various methods for the formation of structural properties of molded dispersed materials in various industries. The paper presents the technological capabilities of promising technologies for production of iron ore pellets based on the heat-power spraying of wet charge on pelletizer’s charge skull and pelletized materials. The physical possibilities of heat-power spraying of wet charge in the forced nucleation and in the process of forming the iron ore pellets’ structural properties are disclosed at the stage of pelletizing. The technical features and production operations of the main technologies for wet charge spraying and the design features of devices for obtaining pellets are shown. The paper describes the experimental unit and technology for the forced nucleation. The macro- and microstructure of the germ mass at forced nucleation were studied. Principles of the formation of regulated structure and improved metallurgical properties in iron ore pellets were substantiated. The article presents the description and characteristics of structural changes on the surface of the sprayed charge layer. A hypothesis was put forward about the structural correspondence of geometric dimensions and relief of charge lappings and cavities in the sprayed layer with the nature of porosity and germ structure. The germ mass affects the pellets’ structural properties. The author obtained the dependences of structural changes’ relative values on the sprayed layer surface on pressure of air-charge jet and particle size of the sprayed charge. There is relationship between geometric dimensions of the sprayed charge layer and the structural changes’ size. A probable mechanism of porosity formation in the germ mass during heat-power spraying of a wet charge onto the pelletizer skull was formulated. The aerodynamic characteristics of air-charge jet influence the formation of porosity. New possibilities of heat-power spraying of wet charge can intensify pellets production and improve their quality.
{"title":"Possibilities of heat-power spraying of wet charge during formation of structural properties of agglomerated iron ore materials","authors":"V. M. Pavlovets","doi":"10.17073/0368-0797-2024-1-19-26","DOIUrl":"https://doi.org/10.17073/0368-0797-2024-1-19-26","url":null,"abstract":"The substantiated problem of improving the structural properties of agglomerated metallurgical raw materials is associated with the formation of a favorable pore structure in iron ore pellets. The author analyzed various methods for the formation of structural properties of molded dispersed materials in various industries. The paper presents the technological capabilities of promising technologies for production of iron ore pellets based on the heat-power spraying of wet charge on pelletizer’s charge skull and pelletized materials. The physical possibilities of heat-power spraying of wet charge in the forced nucleation and in the process of forming the iron ore pellets’ structural properties are disclosed at the stage of pelletizing. The technical features and production operations of the main technologies for wet charge spraying and the design features of devices for obtaining pellets are shown. The paper describes the experimental unit and technology for the forced nucleation. The macro- and microstructure of the germ mass at forced nucleation were studied. Principles of the formation of regulated structure and improved metallurgical properties in iron ore pellets were substantiated. The article presents the description and characteristics of structural changes on the surface of the sprayed charge layer. A hypothesis was put forward about the structural correspondence of geometric dimensions and relief of charge lappings and cavities in the sprayed layer with the nature of porosity and germ structure. The germ mass affects the pellets’ structural properties. The author obtained the dependences of structural changes’ relative values on the sprayed layer surface on pressure of air-charge jet and particle size of the sprayed charge. There is relationship between geometric dimensions of the sprayed charge layer and the structural changes’ size. A probable mechanism of porosity formation in the germ mass during heat-power spraying of a wet charge onto the pelletizer skull was formulated. The aerodynamic characteristics of air-charge jet influence the formation of porosity. New possibilities of heat-power spraying of wet charge can intensify pellets production and improve their quality.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"38 20","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140434908","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: 10.17073/0368-0797-2023-6-760-767
V. V. Aksenova, A. V. Pavlov, G. M. Markov
Modern Russian steelmaking plants use predominantly alumina-containing materials for liquefying lime in a ladle-furnace unit, which replaced fluorspar. Alumina-containing materials currently available on the market cannot be used directly in steelmaking without preliminary preparation (refining, heat treatment or briquetting), or are simply unsuitable for ladle processing of steel. This work describes laboratory studies on the production of refining alumina-containing fluxes by sintering in units such as machines for pellets firing or producing agglomerate (in the temperature range of 1200 – 1500 °C) from clean metallurgical waste (fine dust from the production of alumina and burnt lime), meeting the requirements of steelmaking plants by chemical composition and mechanical properties. A comparison was made of sintering technological schemes with the introduction of hydrated lime and a mixture of hydrated lime and calcium carbonate in a 1:1 ratio as a source of CaO. We determined that the maximum permissible CaO content in sintered briquettes when using a mixture of hydrated lime and calcium carbonate in the charge, which does not lead to hydration destruction in air, is in the range of 2.3 - 3.6 %, depending on the holding temperature. The maximum permissible content of Al2O3 in sintered briquettes when using hydrated lime in the charge, which does not lead to hydration destruction in air, is in the range of 9.5 – 31.7 %, depending on the holding temperature. In existing fuel units it is possible to obtain fluxes by sintering only when using hydrated lime as a source of CaO, because adding calcium carbonate to the charge (9 – 22 %) requires an increase in holding temperature (above 1500 °C) or holding time (more than 25 min).
{"title":"Production of refining alumina-containing fluxes by sintering from technogenic raw materials","authors":"V. V. Aksenova, A. V. Pavlov, G. M. Markov","doi":"10.17073/0368-0797-2023-6-760-767","DOIUrl":"https://doi.org/10.17073/0368-0797-2023-6-760-767","url":null,"abstract":"Modern Russian steelmaking plants use predominantly alumina-containing materials for liquefying lime in a ladle-furnace unit, which replaced fluorspar. Alumina-containing materials currently available on the market cannot be used directly in steelmaking without preliminary preparation (refining, heat treatment or briquetting), or are simply unsuitable for ladle processing of steel. This work describes laboratory studies on the production of refining alumina-containing fluxes by sintering in units such as machines for pellets firing or producing agglomerate (in the temperature range of 1200 – 1500 °C) from clean metallurgical waste (fine dust from the production of alumina and burnt lime), meeting the requirements of steelmaking plants by chemical composition and mechanical properties. A comparison was made of sintering technological schemes with the introduction of hydrated lime and a mixture of hydrated lime and calcium carbonate in a 1:1 ratio as a source of CaO. We determined that the maximum permissible CaO content in sintered briquettes when using a mixture of hydrated lime and calcium carbonate in the charge, which does not lead to hydration destruction in air, is in the range of 2.3 - 3.6 %, depending on the holding temperature. The maximum permissible content of Al2O3 in sintered briquettes when using hydrated lime in the charge, which does not lead to hydration destruction in air, is in the range of 9.5 – 31.7 %, depending on the holding temperature. In existing fuel units it is possible to obtain fluxes by sintering only when using hydrated lime as a source of CaO, because adding calcium carbonate to the charge (9 – 22 %) requires an increase in holding temperature (above 1500 °C) or holding time (more than 25 min).","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":" 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139142025","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: 10.17073/0368-0797-2023-6-709-717
I. V. Vlasov, A. I. Gordienko, A. E. Kuznetsova, V. Semenchuk
The work presents the study of structure and mechanical properties anisotropy of a metal wall obtained using electric arc wire 3D printing (WAAM) with ER70S-6 wire. The layers were deposited in the protective gases of carbon dioxide and argon. As a result of structural studies, it was found that the internal structure of the model product in form of a wall can be divided into three zones. Repeated heating, cooling cycles and degree of accumulated heat influence the formation of different wall zones. As a result of rapid heat removal to the substrate during deposition of the first layers, the wall base (zone 1) contains large elongated grains with acicular ferrite structure. The wall middle part (zone 2) consists of ferrite-pearlite structure, which was formed as a result of recrystallization under conditions of repeated heating and cooling during 3D printing. The size of ferrite grains in zone 2 varies from 11 to 16.3 µm with increasing the number of layers. The gradual accumulation of heat during 3D printing led to the formation of structures in zone 3 under conditions of overheating and a reduced cooling rate. As a result, the wall upper part (zone 3) consists of large ferrite grains (up to 29.8 μm), sorbite, and a small proportion of Widemanstatten ferrite and acicular ferrite. It is shown that the most uniform level of mechanical characteristics (σ0.2 = 340 MPa, σu = 470 MPa, ε = 28 %) correspond to the samples cut from zone 2 in a direction parallel to 3D printing direction. The samples cut in the vertical direction relative to 3D printing and from zone 3 show the lowest level of microhardness and mechanical characteristics (σ0.2 = 260 MPa, σu = 425 MPa, ε = 20 %).
{"title":"Structure and mechanical properties anisotropy of a steel product manufactured by layer-by-layer electric arc wire 3D printing","authors":"I. V. Vlasov, A. I. Gordienko, A. E. Kuznetsova, V. Semenchuk","doi":"10.17073/0368-0797-2023-6-709-717","DOIUrl":"https://doi.org/10.17073/0368-0797-2023-6-709-717","url":null,"abstract":"The work presents the study of structure and mechanical properties anisotropy of a metal wall obtained using electric arc wire 3D printing (WAAM) with ER70S-6 wire. The layers were deposited in the protective gases of carbon dioxide and argon. As a result of structural studies, it was found that the internal structure of the model product in form of a wall can be divided into three zones. Repeated heating, cooling cycles and degree of accumulated heat influence the formation of different wall zones. As a result of rapid heat removal to the substrate during deposition of the first layers, the wall base (zone 1) contains large elongated grains with acicular ferrite structure. The wall middle part (zone 2) consists of ferrite-pearlite structure, which was formed as a result of recrystallization under conditions of repeated heating and cooling during 3D printing. The size of ferrite grains in zone 2 varies from 11 to 16.3 µm with increasing the number of layers. The gradual accumulation of heat during 3D printing led to the formation of structures in zone 3 under conditions of overheating and a reduced cooling rate. As a result, the wall upper part (zone 3) consists of large ferrite grains (up to 29.8 μm), sorbite, and a small proportion of Widemanstatten ferrite and acicular ferrite. It is shown that the most uniform level of mechanical characteristics (σ0.2 = 340 MPa, σu = 470 MPa, ε = 28 %) correspond to the samples cut from zone 2 in a direction parallel to 3D printing direction. The samples cut in the vertical direction relative to 3D printing and from zone 3 show the lowest level of microhardness and mechanical characteristics (σ0.2 = 260 MPa, σu = 425 MPa, ε = 20 %).","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":" 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139143022","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: 10.17073/0368-0797-2023-6-659-665
Y. Pochivalov
The article describes the features of grain structure formation and mechanical properties of low-alloy steel 10G2FBYu after rolling in flat and embossed rolls under the conditions of ordinary and electroplastic deformation. When rolling in embossed rolls, a significant non-uniformity of deformation is achieved over the rolling cross-section, expressed in localized macroshifts directed at an angle of 45° to the rolling plane. It is shown that local shear deformation during rolling in embossed rolls leads to an increase in the ultimate strength of the steel under study with a decrease in plasticity of the rolled material. Rolling 10G2FBYu steel in embossed rolls under conditions of electroplasticity provides maximum strength characteristics with a high hardening coefficient at the stage of macrodeformation. At the same time, the plasticity is maintained at a level sufficient for technological purposes. Structural metallographic and electron microscopic studies showed that increase in strength of steel when rolling in embossed rolls under conditions of electroplastic effect is caused by the refinement of ferrite grains to sizes less than 0.5 µm. Fractographic studies revealed changes in the nature of fracture in steel during rolling in embossed rolls, which is expressed in appearance of areas of brittle fracture in the rolled samples. Rolling under conditions of electroplasticity increases the proportion of ductile fracture and ductility of 10G2FBYu steel.
{"title":"Structure and properties of low-alloy steel 10G2FBYu after rolling in embossed rolls under conditions of electroplasticity","authors":"Y. Pochivalov","doi":"10.17073/0368-0797-2023-6-659-665","DOIUrl":"https://doi.org/10.17073/0368-0797-2023-6-659-665","url":null,"abstract":"The article describes the features of grain structure formation and mechanical properties of low-alloy steel 10G2FBYu after rolling in flat and embossed rolls under the conditions of ordinary and electroplastic deformation. When rolling in embossed rolls, a significant non-uniformity of deformation is achieved over the rolling cross-section, expressed in localized macroshifts directed at an angle of 45° to the rolling plane. It is shown that local shear deformation during rolling in embossed rolls leads to an increase in the ultimate strength of the steel under study with a decrease in plasticity of the rolled material. Rolling 10G2FBYu steel in embossed rolls under conditions of electroplasticity provides maximum strength characteristics with a high hardening coefficient at the stage of macrodeformation. At the same time, the plasticity is maintained at a level sufficient for technological purposes. Structural metallographic and electron microscopic studies showed that increase in strength of steel when rolling in embossed rolls under conditions of electroplastic effect is caused by the refinement of ferrite grains to sizes less than 0.5 µm. Fractographic studies revealed changes in the nature of fracture in steel during rolling in embossed rolls, which is expressed in appearance of areas of brittle fracture in the rolled samples. Rolling under conditions of electroplasticity increases the proportion of ductile fracture and ductility of 10G2FBYu steel.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":" 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139143496","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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