Isothermal hardening (Austempering) of iron-based alloys with medium and high carbon content, which creates a metallic structure called bainite, is used to increase the strength and impact toughness of the metal. The parts are heated to a temperature approximately 200-300 °C below the solidification temperature of the metal, then cooled (hardened) fairly quickly to the temperature of the beginning of the bainite transformation, avoiding the martensitic transformation, and kept for a time sufficient to obtain the given bainite microstructure. IG is particularly advantageous for castings from high-strength cast iron (HC), adding to the high foundry performance of the growth of the mechanical characteristics of this alloy to the level of steel strength at a lower cost, density and energy consumption of HC casting compared to steel. The article examines methods of heat treatment of castings removed in a hot austenitic state from a sand mold, as a type of heat treatment of iron-carbon alloys combined with their casting. For this, casting according to gasification models was used, in which, due to the high fluidity of the dry sand of the casting mold, it is not difficult to remove hot castings from the mold for tempering. A number of IG methods previously patented by the FTIMS Institute of the National Academy of Sciences of the Russian Academy of Sciences have been supplemented by a new method of such hardening in a dosed amount of water, taking into account the effect of its film boiling. The new method includes the calculation of the optimal mass of quenching liquid - water with the aim of heating this mass of water to its boiling point at the time of cooling of the casting to the given temperature of the bainite transformation of the metal. The method saves the quenching liquid, simplifies the control of the duration of cooling, during which it allows the transportation of castings between the foundry and heat-treatment sections, which, in general, saves time, energy resources and the area of the workshop for obtaining heat-treated castings. Keywords: isothermal hardening, heat treatment, castings, austenite, lost foam casting.
中碳含量和高碳含量铁基合金的等温淬火（奥氏体淬火）可产生一种称为贝氏体的金属结构，用于提高金属的强度和冲击韧性。将零件加热到低于金属凝固温度约 200-300 °C 的温度，然后快速冷却（淬火）到贝氏体转变开始的温度，避免马氏体转变，并保持足够的时间以获得特定的贝氏体微观结构。IG对高强度铸铁（HC）的铸件尤其有利，与钢相比，HC铸件的成本、密度和能耗更低，而且这种合金的机械性能增长到钢的强度水平，从而增加了高铸造性能。文章探讨了从砂型中取出的热奥氏体状态铸件的热处理方法，作为铁碳合金热处理的一种类型，与铸件相结合。为此，采用了气化模型铸造法，在这种方法中，由于铸型干砂的流动性高，从铸型中取出热铸件进行回火并不困难。在俄罗斯科学院国家科学院 FTIMS 研究所之前获得专利的一系列 IG 方法的基础上，考虑到水膜沸腾的影响，又增加了一种在定量水中进行此类硬化的新方法。新方法包括计算淬火液--水的最佳质量，目的是在铸件冷却到金属贝氏体转变的给定温度时将该质量的水加热到沸点。这种方法节省了淬火液，简化了冷却持续时间的控制，在冷却期间可以在铸造车间和热处理车间之间运输铸件，总体而言，节省了时间、能源和车间用于获得热处理铸件的面积。关键词：等温淬火、热处理、铸件、奥氏体、消失模铸造。
{"title":"Isothermal hardening of iron-carbon alloys combined with their casting","authors":"V.S. Doroshenko, P. Kaliuzhnyi","doi":"10.15407/mom2024.01.047","DOIUrl":"https://doi.org/10.15407/mom2024.01.047","url":null,"abstract":"Isothermal hardening (Austempering) of iron-based alloys with medium and high carbon content, which creates a metallic structure called bainite, is used to increase the strength and impact toughness of the metal. The parts are heated to a temperature approximately 200-300 °C below the solidification temperature of the metal, then cooled (hardened) fairly quickly to the temperature of the beginning of the bainite transformation, avoiding the martensitic transformation, and kept for a time sufficient to obtain the given bainite microstructure. IG is particularly advantageous for castings from high-strength cast iron (HC), adding to the high foundry performance of the growth of the mechanical characteristics of this alloy to the level of steel strength at a lower cost, density and energy consumption of HC casting compared to steel. The article examines methods of heat treatment of castings removed in a hot austenitic state from a sand mold, as a type of heat treatment of iron-carbon alloys combined with their casting. For this, casting according to gasification models was used, in which, due to the high fluidity of the dry sand of the casting mold, it is not difficult to remove hot castings from the mold for tempering. A number of IG methods previously patented by the FTIMS Institute of the National Academy of Sciences of the Russian Academy of Sciences have been supplemented by a new method of such hardening in a dosed amount of water, taking into account the effect of its film boiling. The new method includes the calculation of the optimal mass of quenching liquid - water with the aim of heating this mass of water to its boiling point at the time of cooling of the casting to the given temperature of the bainite transformation of the metal. The method saves the quenching liquid, simplifies the control of the duration of cooling, during which it allows the transportation of castings between the foundry and heat-treatment sections, which, in general, saves time, energy resources and the area of the workshop for obtaining heat-treated castings. Keywords: isothermal hardening, heat treatment, castings, austenite, lost foam casting.","PeriodicalId":508191,"journal":{"name":"Metaloznavstvo ta obrobka metalìv","volume":"58 19","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140364920","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}
The strain resistance of a metal, its intensity of hardening, directly depends on the evolution of defects in the crystal lattice. The positive influence of a magnetic field (MF) on the movement of dislocations and their interaction with stoppers (magnetoplastic effect) is known. For the practical use of MF in forging technologies, generalized data on the strengthening of metals during plastic deformation are required. The results of using a constant MF with induction up to 1,2 T in the processes of testing samples for tension and compression were studied. Tensile tests were carried out on samples of steels St3, 20, U8, 40Cr, 09Cr16Ni4Nb, X10CrNiTi18-10, copper M3 and compression tests on steels St3, 09Cr16Ni4Nb, X10CrNiTi18-10, copper M3. Curves of metal hardening during deformation are plotted in the coordinates flow stress – logarithmic strain. The flow stress is determined by the ratio of the load to the cross-sectional area of the sample valid for a given moment of testing under uniform deformation. The change in flow stress of metals is described by the power function of the Ludwik-Hollomon equation. In tension and compression of ferromagnetic steels St3, 20, 40Cr, U8 and 09Cr16Ni4Nb, the impact of MF leads to an increase in the intensity of their hardening. This is most evident in hardened or high-strength steels. But for St3 steel softened by annealing, the effect is the opposite - in MF the intensity of hardening is somewhat less. Tension in MF of paramagnetic steel X10CrNiTi18-10 showed an increase in the intensity of hardening, but compression showed its decrease. Tension and compression of M3 copper in MF occur with a slight decrease in the intensity of hardening. The experiments carried out revealed the main effect of MF at the initial stage of deformation. The hardening curves were divided into straight and parabolic sections with the hardening coefficients determined for each of them. The main effect of MT on the primary stage of linear hardening has been revealed, where a decrease in the intensity of hardening (St3, 40Cr, X10CrNiTi18-10, M3), an increase (St3 and X10CrNiTi18-10) or a reduction (St3 annealed) in the duration of this stage is observed. Keywords: magnetoplasticity, tension, compression, hardening, stress, strain.
{"title":"Peculiarities of steel hardening under deformation conditions with external influence of a magnetic field","authors":"C. Dong, М. Kraiev","doi":"10.15407/mom2024.01.040","DOIUrl":"https://doi.org/10.15407/mom2024.01.040","url":null,"abstract":"The strain resistance of a metal, its intensity of hardening, directly depends on the evolution of defects in the crystal lattice. The positive influence of a magnetic field (MF) on the movement of dislocations and their interaction with stoppers (magnetoplastic effect) is known. For the practical use of MF in forging technologies, generalized data on the strengthening of metals during plastic deformation are required. The results of using a constant MF with induction up to 1,2 T in the processes of testing samples for tension and compression were studied. Tensile tests were carried out on samples of steels St3, 20, U8, 40Cr, 09Cr16Ni4Nb, X10CrNiTi18-10, copper M3 and compression tests on steels St3, 09Cr16Ni4Nb, X10CrNiTi18-10, copper M3. Curves of metal hardening during deformation are plotted in the coordinates flow stress – logarithmic strain. The flow stress is determined by the ratio of the load to the cross-sectional area of the sample valid for a given moment of testing under uniform deformation. The change in flow stress of metals is described by the power function of the Ludwik-Hollomon equation. In tension and compression of ferromagnetic steels St3, 20, 40Cr, U8 and 09Cr16Ni4Nb, the impact of MF leads to an increase in the intensity of their hardening. This is most evident in hardened or high-strength steels. But for St3 steel softened by annealing, the effect is the opposite - in MF the intensity of hardening is somewhat less. Tension in MF of paramagnetic steel X10CrNiTi18-10 showed an increase in the intensity of hardening, but compression showed its decrease. Tension and compression of M3 copper in MF occur with a slight decrease in the intensity of hardening. The experiments carried out revealed the main effect of MF at the initial stage of deformation. The hardening curves were divided into straight and parabolic sections with the hardening coefficients determined for each of them. The main effect of MT on the primary stage of linear hardening has been revealed, where a decrease in the intensity of hardening (St3, 40Cr, X10CrNiTi18-10, M3), an increase (St3 and X10CrNiTi18-10) or a reduction (St3 annealed) in the duration of this stage is observed. Keywords: magnetoplasticity, tension, compression, hardening, stress, strain.","PeriodicalId":508191,"journal":{"name":"Metaloznavstvo ta obrobka metalìv","volume":"61 17","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140367929","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}
In a modern world, additive manufacturing of metal products has reached significant volumes and variety of applied alloys. 3D-printing technologies make it possible to obtain parts with reduced mass, increased reliability, single products, experimental parts and elements designs with complex geometry and configuration. Disadvantages of metal parts additive manufacturing include anisotropy of chemical composition and properties, non-equilibrium structural-phase state, structural micro- and macrodefects and some other features, that require post-processing of as-printed products. Most often, heat treatment and its combination with microforging or intensive surface plastic deformation are used for this purpose. The manuscript provides an analytical review of the advantages of using ultrasonic technologies to support 3D-printing and post-processing of additively manufactured products. Special attention is paid to ultrasonic impact treatment (UIT). The equipment for providing UIT is compact, energy-saving and easy to use. It is noted, that this technology makes it possible to effectively reduce surface defects of printed parts, increase its hardness and fatigue strength. At the same time, nanostructuring and changes in the structural and phase state of the modified layers are also occured. It is also noted, that UIT may provide surface strengthening to a depth of ~500 μm, saturating it with alloying elements and compounds, and for conventionally produced parts, like as–cast, deformed and powder sintered – it is significantly more effective than most other similar methods. The prospects of using ultrasonic technologies to improve quality and level of operational and mechanical characteristics of additively manufactured metal parts, including the needs of aircraft construction, are outlined. Keywords: additive technologies, 3D-printing, ultrasonic impact treatment, UIT, surface strengthening, cavitation, vibration polishing, fatigue strength, Grade5, AlSi10Mg, Inconel-718.
在当今世界，金属产品的增材制造已达到相当大的规模，应用的合金种类也越来越多。三维打印技术可以获得质量更小、可靠性更高的零件、单一产品、实验零件以及具有复杂几何形状和配置的元件设计。金属零件增材制造的缺点包括化学成分和性能的各向异性、非平衡结构相态、结构微观和宏观缺陷以及其他一些需要对打印后产品进行后处理的特征。为此，通常采用热处理及其与微锻造或强化表面塑性变形相结合的方法。该手稿分析了使用超声波技术来支持三维打印和增材制造产品后处理的优势。其中特别关注超声波冲击处理（UIT）。提供 UIT 的设备结构紧凑、节能且易于使用。这项技术可以有效减少印刷部件的表面缺陷，提高其硬度和疲劳强度。同时，改性层的纳米结构和相态也会发生变化。我们还注意到，UIT 可使表面强化深度达到约 500 μm，并使合金元素和化合物达到饱和，对于传统生产的零件，如铸造、变形和粉末烧结，其效果明显优于大多数其他类似方法。本文概述了使用超声波技术提高增材制造金属零件的质量和操作水平以及机械特性的前景，包括飞机制造的需求。关键词：快速成型技术、3D 打印、超声波冲击处理、UIT、表面强化、空化、振动抛光、疲劳强度、Grade5、AlSi10Mg、Inconel-718。
{"title":"Application of ultrasonic surface treatment technologies in metals and alloys additive manufacturing","authors":"S. Voloshko, A. Burmak, A. Orlov, M. Voron","doi":"10.15407/mom2024.01.028","DOIUrl":"https://doi.org/10.15407/mom2024.01.028","url":null,"abstract":"In a modern world, additive manufacturing of metal products has reached significant volumes and variety of applied alloys. 3D-printing technologies make it possible to obtain parts with reduced mass, increased reliability, single products, experimental parts and elements designs with complex geometry and configuration. Disadvantages of metal parts additive manufacturing include anisotropy of chemical composition and properties, non-equilibrium structural-phase state, structural micro- and macrodefects and some other features, that require post-processing of as-printed products. Most often, heat treatment and its combination with microforging or intensive surface plastic deformation are used for this purpose. The manuscript provides an analytical review of the advantages of using ultrasonic technologies to support 3D-printing and post-processing of additively manufactured products. Special attention is paid to ultrasonic impact treatment (UIT). The equipment for providing UIT is compact, energy-saving and easy to use. It is noted, that this technology makes it possible to effectively reduce surface defects of printed parts, increase its hardness and fatigue strength. At the same time, nanostructuring and changes in the structural and phase state of the modified layers are also occured. It is also noted, that UIT may provide surface strengthening to a depth of ~500 μm, saturating it with alloying elements and compounds, and for conventionally produced parts, like as–cast, deformed and powder sintered – it is significantly more effective than most other similar methods. The prospects of using ultrasonic technologies to improve quality and level of operational and mechanical characteristics of additively manufactured metal parts, including the needs of aircraft construction, are outlined. Keywords: additive technologies, 3D-printing, ultrasonic impact treatment, UIT, surface strengthening, cavitation, vibration polishing, fatigue strength, Grade5, AlSi10Mg, Inconel-718.","PeriodicalId":508191,"journal":{"name":"Metaloznavstvo ta obrobka metalìv","volume":"5 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140367621","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}
A wide range of products, including pipes, is made from cast billets of the Al-Mg alloy. It is known that the alloy effectively combines a complex of special properties. The article is devoted to the study of the possibilities of improving the properties of AMg6 alloy castings by applying vibration during casting and cooling. The vibration of the melt in the casting mold during cooling and solidification is an effective auxiliary tool for controlling the structure of alloys, which is universally integrated into the technological process of obtaining cast blanks. In this work, the influence of the melt pouring temperature and vibration (amplitude 0.2 mm, frequency 60 Hz) on the size, morphology and nature of the arrangement of phases and mechanical properties of the cast metal of tube blanks made of AMg6 alloy was investigated. It was found that the use of vibration leads to a 10-fold decrease in grain size. It was found that Mg2Si inclusions did not change shape under the influence of vibration, but decreased in size by 1.5 times. Similar changes in the structure of the alloy are characteristic of the metal, which was cooled at a higher speed and with the use of vibration. This made it possible to obtain the hardness of the AMg6 alloy up to 717 MPa, which is higher than that of the standard material. Grinding structural components makes it possible to reduce the duration of heat treatment of the alloy Keywords: AMг6 alloy, cast pipe billets, vibration, structure, mechanical properties.
{"title":"Influence of melt temperature and vibration on the structure of AMg6 alloy","authors":"V. Shkolyarenko, O.V. Seredenko, I. Baranov","doi":"10.15407/mom2024.01.059","DOIUrl":"https://doi.org/10.15407/mom2024.01.059","url":null,"abstract":"A wide range of products, including pipes, is made from cast billets of the Al-Mg alloy. It is known that the alloy effectively combines a complex of special properties. The article is devoted to the study of the possibilities of improving the properties of AMg6 alloy castings by applying vibration during casting and cooling. The vibration of the melt in the casting mold during cooling and solidification is an effective auxiliary tool for controlling the structure of alloys, which is universally integrated into the technological process of obtaining cast blanks. In this work, the influence of the melt pouring temperature and vibration (amplitude 0.2 mm, frequency 60 Hz) on the size, morphology and nature of the arrangement of phases and mechanical properties of the cast metal of tube blanks made of AMg6 alloy was investigated. It was found that the use of vibration leads to a 10-fold decrease in grain size. It was found that Mg2Si inclusions did not change shape under the influence of vibration, but decreased in size by 1.5 times. Similar changes in the structure of the alloy are characteristic of the metal, which was cooled at a higher speed and with the use of vibration. This made it possible to obtain the hardness of the AMg6 alloy up to 717 MPa, which is higher than that of the standard material. Grinding structural components makes it possible to reduce the duration of heat treatment of the alloy Keywords: AMг6 alloy, cast pipe billets, vibration, structure, mechanical properties.","PeriodicalId":508191,"journal":{"name":"Metaloznavstvo ta obrobka metalìv","volume":"77 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140368561","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}
The article presents the research results on the structure and properties of new self-lubricating bearing composites based on grinding wastes of high-alloyed steel 8X4V2MFS2 with additives of CaF2 solid lubricant. The new composites are designed to operate in friction units of printing machines at rotational speeds of 600˗800 rpm and increased loads of up to 3.0 MPa. It is shown that the application of the developed technology ensures the formation of a fine-grained heterophase structure of the new composite. The formed structure is a metal matrix base made of regenerated grinding waste from 8X4V2MFS2 steel, consisting of a high-alloy α-solid solution and solid grains of alloying elements’ carbides, as well as a uniformly distributed solid lubricant CaF2. This structure ensured the formation of the new composite’s physical, mechanical and tribological properties high level. In the process of friction, antifriction films were formed on the contact surfaces, which provided a self-lubricating mode. Comparative friction and wear tests have shown significant advantages of the new waste composite compared to cast brass L63, which is traditionally used in friction units of printing equipment. The determined level of physical, mechanical, and tribological characteristics makes it possible to recommend the studied material for use in friction units of printing equipment operating at elevated rotational speeds of 600˗800 rpm and loads up to 3.0 MPa in air. The studies have shown the prospects of using a wide range of valuable metal grinding waste in the repeated production cycle for the manufacture of high-quality composites. The reuse of such waste will make a significant contribution to the protection of the environment from pollution associated with human industrial activity and will help reduce its negative effect on the ecosystem. Keywords: grinding waste, high-alloyed steel, technology, composite bearing, microstructure, solid lubricant, properties, antifriction films, printing machines.
{"title":"Structure and properties of new bearing composites based on steel waste for severe operating conditions of printing machines","authors":"T. A. Roik, V. Kholiavko","doi":"10.15407/mom2024.01.003","DOIUrl":"https://doi.org/10.15407/mom2024.01.003","url":null,"abstract":"The article presents the research results on the structure and properties of new self-lubricating bearing composites based on grinding wastes of high-alloyed steel 8X4V2MFS2 with additives of CaF2 solid lubricant. The new composites are designed to operate in friction units of printing machines at rotational speeds of 600˗800 rpm and increased loads of up to 3.0 MPa. It is shown that the application of the developed technology ensures the formation of a fine-grained heterophase structure of the new composite. The formed structure is a metal matrix base made of regenerated grinding waste from 8X4V2MFS2 steel, consisting of a high-alloy α-solid solution and solid grains of alloying elements’ carbides, as well as a uniformly distributed solid lubricant CaF2. This structure ensured the formation of the new composite’s physical, mechanical and tribological properties high level. In the process of friction, antifriction films were formed on the contact surfaces, which provided a self-lubricating mode. Comparative friction and wear tests have shown significant advantages of the new waste composite compared to cast brass L63, which is traditionally used in friction units of printing equipment. The determined level of physical, mechanical, and tribological characteristics makes it possible to recommend the studied material for use in friction units of printing equipment operating at elevated rotational speeds of 600˗800 rpm and loads up to 3.0 MPa in air. The studies have shown the prospects of using a wide range of valuable metal grinding waste in the repeated production cycle for the manufacture of high-quality composites. The reuse of such waste will make a significant contribution to the protection of the environment from pollution associated with human industrial activity and will help reduce its negative effect on the ecosystem. Keywords: grinding waste, high-alloyed steel, technology, composite bearing, microstructure, solid lubricant, properties, antifriction films, printing machines.","PeriodicalId":508191,"journal":{"name":"Metaloznavstvo ta obrobka metalìv","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140366098","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}
We studied steel sheets DC04 (0.06% C, up to 0.35% Mn, up to 0.40% Si, ~ 0.025% S and P) with a thickness of 0.95 mm as delivered. Sheets of A4 size were annealed in a laboratory oven (6000C in an argon atmosphere, hold for 1 hour). The structure of DC04 steel sheets after recrystallization annealing was studied. The microstructure of the steel sheets under study is presented from the side of the rolling plane and in the section of the sheet perpendicular to the direction. In the plane of the sheets, the grains are elongated; in the cross section, the grains are approximately equiaxed. Pole figures (PF) were constructed based on the results of electron backscatter diffraction (EBSD) on a LEO 1455 VP electron microscope at an accelerating voltage of 20 kV from the plane of the sheets and from the section of the sheet perpendicular to the rolling direction. To improve statistics, PF were constructed by averaging reflex stereographic projections from 20 different representative volumes of material relative to the rolling direction and transverse direction. The texture and anisotropy of Young's modulus in the plane and cross section of steel sheets DC04 after recrystallization annealing was studied using EBSD method. A connection has been obtained between ideal orientations that describe the texture in two mutually perpendicular planes and the corresponding integral characteristics of texture (ICT). Rectangular samples with a length of 100 and a width of 10 mm at different angles to the rolling direction every 150 to measure Young's modulus. Samples were processed in a bag to ensure uniform dimensions. Young's modulus was determined by the dynamic method from the frequency of natural transverse vibrations. Three batches of samples were used to construct Young's modulus anisotropy curves. The anisotropy of the Young's modulus in the plane of steel sheets, calculated from the ICT based on the results of EBSD data, is in good agreement with the results of direct measurements. The value of Young's modulus in the direction normal to the plane of the sheet and in the section plane in the direction normal to the plane of the sheet, calculated from the ICT and the values of the compliance constants of iron, coincide. Keywords: texture, pole figure, anisotropy, integral characteristics of texture, Young's modulus.
{"title":"Recrystallization texture and anisotropy of elastic properties of DC04 steel sheets","authors":"V.A. Volchok, Z.A. Briukhanov, S.I. Iovchev, A.O. Briukhanov, D.O. Yefimenko","doi":"10.15407/mom2024.01.018","DOIUrl":"https://doi.org/10.15407/mom2024.01.018","url":null,"abstract":"We studied steel sheets DC04 (0.06% C, up to 0.35% Mn, up to 0.40% Si, ~ 0.025% S and P) with a thickness of 0.95 mm as delivered. Sheets of A4 size were annealed in a laboratory oven (6000C in an argon atmosphere, hold for 1 hour). The structure of DC04 steel sheets after recrystallization annealing was studied. The microstructure of the steel sheets under study is presented from the side of the rolling plane and in the section of the sheet perpendicular to the direction. In the plane of the sheets, the grains are elongated; in the cross section, the grains are approximately equiaxed. Pole figures (PF) were constructed based on the results of electron backscatter diffraction (EBSD) on a LEO 1455 VP electron microscope at an accelerating voltage of 20 kV from the plane of the sheets and from the section of the sheet perpendicular to the rolling direction. To improve statistics, PF were constructed by averaging reflex stereographic projections from 20 different representative volumes of material relative to the rolling direction and transverse direction. The texture and anisotropy of Young's modulus in the plane and cross section of steel sheets DC04 after recrystallization annealing was studied using EBSD method. A connection has been obtained between ideal orientations that describe the texture in two mutually perpendicular planes and the corresponding integral characteristics of texture (ICT). Rectangular samples with a length of 100 and a width of 10 mm at different angles to the rolling direction every 150 to measure Young's modulus. Samples were processed in a bag to ensure uniform dimensions. Young's modulus was determined by the dynamic method from the frequency of natural transverse vibrations. Three batches of samples were used to construct Young's modulus anisotropy curves. The anisotropy of the Young's modulus in the plane of steel sheets, calculated from the ICT based on the results of EBSD data, is in good agreement with the results of direct measurements. The value of Young's modulus in the direction normal to the plane of the sheet and in the section plane in the direction normal to the plane of the sheet, calculated from the ICT and the values of the compliance constants of iron, coincide. Keywords: texture, pole figure, anisotropy, integral characteristics of texture, Young's modulus.","PeriodicalId":508191,"journal":{"name":"Metaloznavstvo ta obrobka metalìv","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140365499","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}
The rapid development of mechanical engineering and electrical engineering requires alloys that have high electrical conductivity and a high level of mechanical properties, including strength at elevated temperatures. Pure and low-alloyed copper are ductile, but low-strength materials, which prevents their application in many areas. The solution of such problem can be in alloying with metals that would increase strength characteristics while maintaining electrical conductivity as much as possible, including at high current and temperature loads. The main alloying elements analyzed in this work as effective strengthening components were Cr, Zr, and V. It is shown that the increase in strength while maintaining electrical conductivity depends to a greater extent on the chromium content, the concentration of which in alloys can reach 5-10 wt. %. It was established that to achieve optimal characteristics of strength and electrical conductivity, the concentration of chromium can be close to 0,1 wt. %, and zirconium - up to 0,2 wt. %. At the same time, both for alloys with a high chromium content and in low-alloyed compositions, the characteristics of strength and electrical conductivity can differ by only 10-20%. In the vast majority of cases, copper alloys with chromium and zirconium undergo a specific, sometimes compositional and multi-stage, deformation treatment, after which a fine crystalline structure with nano-sized allocations of strengthening dispersoid phases can be formed. All considered alloys show similar technological features of obtaining a high level of final properties - homogenization and tempering from temperatures of 900-1000 °С and aging at 500 °С for 2 hours or more. At the same time, the higher the content of chromium and zirconium, the more difficult the deformation and heat treatments will be. Additional microalloying with vanadium in the amount of up to 0.2 wt. % may increase strength without a noticeable decrease in electrical conductivity and without the need for the complication of deformation and heat treatments. Keywords: alloying of copper alloys, Cu-Cr-Zr, Cu-Cr-Zr-V, heat treatment, deformation, electrical conductivity.
{"title":"Creation and processing of copper alloys doped with chromium, zirconium and vanadium","authors":"R. Likhatskyi","doi":"10.15407/mom2023.04.003","DOIUrl":"https://doi.org/10.15407/mom2023.04.003","url":null,"abstract":"The rapid development of mechanical engineering and electrical engineering requires alloys that have high electrical conductivity and a high level of mechanical properties, including strength at elevated temperatures. Pure and low-alloyed copper are ductile, but low-strength materials, which prevents their application in many areas. The solution of such problem can be in alloying with metals that would increase strength characteristics while maintaining electrical conductivity as much as possible, including at high current and temperature loads. The main alloying elements analyzed in this work as effective strengthening components were Cr, Zr, and V. It is shown that the increase in strength while maintaining electrical conductivity depends to a greater extent on the chromium content, the concentration of which in alloys can reach 5-10 wt. %. It was established that to achieve optimal characteristics of strength and electrical conductivity, the concentration of chromium can be close to 0,1 wt. %, and zirconium - up to 0,2 wt. %. At the same time, both for alloys with a high chromium content and in low-alloyed compositions, the characteristics of strength and electrical conductivity can differ by only 10-20%. In the vast majority of cases, copper alloys with chromium and zirconium undergo a specific, sometimes compositional and multi-stage, deformation treatment, after which a fine crystalline structure with nano-sized allocations of strengthening dispersoid phases can be formed. All considered alloys show similar technological features of obtaining a high level of final properties - homogenization and tempering from temperatures of 900-1000 °С and aging at 500 °С for 2 hours or more. At the same time, the higher the content of chromium and zirconium, the more difficult the deformation and heat treatments will be. Additional microalloying with vanadium in the amount of up to 0.2 wt. % may increase strength without a noticeable decrease in electrical conductivity and without the need for the complication of deformation and heat treatments. Keywords: alloying of copper alloys, Cu-Cr-Zr, Cu-Cr-Zr-V, heat treatment, deformation, electrical conductivity.","PeriodicalId":508191,"journal":{"name":"Metaloznavstvo ta obrobka metalìv","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139184234","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}
From the standpoint of systemic and structural-functional approaches, the state and prospects of development of the methodology for regulating and predicting the chemical composition and mechanical properties of grey synthetic cast iron intended for casting production are analysed. Attention is focused on the key intersections of the technological process of manufacturing castings for critical applications. The features, disadvantages, and advantages of the known methods for calculating the charge and adjusting the percentage of chemical elements in the cast iron composition directly during its melting are considered. Ways to take into account the instability of the chemical composition of scrap metal, ferroalloys, and other materials when forming the charge to ensure the quality of pig iron in accordance with the requirements of finished product standards are shown. A promising way to solve this problem in foundry is to use a probabilistic approach and the Monte Carlo method. The article presents formulas for calculating the strength and hardness of cast iron castings with lamellar graphite depending on its carbon equivalent and degree of eutecticity. The peculiarity of the proposed formulas, which gives them enhanced reliability and validity, is that the carbon equivalent and the degree of eutecticity of cast iron in them are determined by the Monte Carlo method using a probabilistic approach with regard to the consideration of the ranges of variation of the content of chemical elements in the cast iron composition regulated in the standard for foundry products. It is noted that the widespread use of thermal derivative express analysis of liquid cast iron in industry is constrained by the lack of a database of reference cooling curves with certain property indicators (chemical composition, microstructure, mechanical and other properties) of cast irons at foundries. Keywords: foundry, cast iron, chemical composition, properties, control, regulation, methodology.
{"title":"Directions for the development of a methodology for regulating the chemical composition and properties of cast iron in foundry production based on a probabilistic approach","authors":"К. Sirenko","doi":"10.15407/mom2023.04.023","DOIUrl":"https://doi.org/10.15407/mom2023.04.023","url":null,"abstract":"From the standpoint of systemic and structural-functional approaches, the state and prospects of development of the methodology for regulating and predicting the chemical composition and mechanical properties of grey synthetic cast iron intended for casting production are analysed. Attention is focused on the key intersections of the technological process of manufacturing castings for critical applications. The features, disadvantages, and advantages of the known methods for calculating the charge and adjusting the percentage of chemical elements in the cast iron composition directly during its melting are considered. Ways to take into account the instability of the chemical composition of scrap metal, ferroalloys, and other materials when forming the charge to ensure the quality of pig iron in accordance with the requirements of finished product standards are shown. A promising way to solve this problem in foundry is to use a probabilistic approach and the Monte Carlo method. The article presents formulas for calculating the strength and hardness of cast iron castings with lamellar graphite depending on its carbon equivalent and degree of eutecticity. The peculiarity of the proposed formulas, which gives them enhanced reliability and validity, is that the carbon equivalent and the degree of eutecticity of cast iron in them are determined by the Monte Carlo method using a probabilistic approach with regard to the consideration of the ranges of variation of the content of chemical elements in the cast iron composition regulated in the standard for foundry products. It is noted that the widespread use of thermal derivative express analysis of liquid cast iron in industry is constrained by the lack of a database of reference cooling curves with certain property indicators (chemical composition, microstructure, mechanical and other properties) of cast irons at foundries. Keywords: foundry, cast iron, chemical composition, properties, control, regulation, methodology.","PeriodicalId":508191,"journal":{"name":"Metaloznavstvo ta obrobka metalìv","volume":"94 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139183867","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}
S. Shypytsyn, E. Isaeva, D. Lykhovey, T. Stepanova, N. Kiryakova
Systemic fundamental research for several decades at the FTIMS of the National Academy of Sciences of Ukraine and the accumulated experience of industrial application have shown that the technology of dispersion nitride hardening, which is based on the alloying of steels with nitrogen and vanadium, is a method of significantly improving the entire complex of physical, mechanical and operational properties of cast and deformed carbon, low-alloy and alloy steels of various functional purposes. The most significant advantage of the steels developed at the FTIMS of the National Academy of Sciences of Ukraine is a simultaneous significant increase in their static and cyclic strength, fracture toughness, thermal strength and heat resistance, wear resistance, annealing, weldability, reduction or complete elimination of the tendency to natural, deformation and warm embrittlement. Medium- and high-carbon pre-eutectoid and eutectoid steels of high strength and wear resistance are widely used in various fields of mechanical engineering. However, they are most widely used for railway wheels and rails. The reliability and operational resource of wheels and rails, which are in extremely harsh operating conditions, mainly determine the technical and economic performance indicators of railway transport. At the same time, existing relatively cheap non-alloyed and low-alloyed medium- and high-carbon wheel and rail steels no longer meet the modern requirements of increased speeds and load capacity of rolling stock. Keywords: carbon steels, dispersion nitride hardening, austenization, tempering, phase redistribution of nitrogen and vanadium.
{"title":"Metallurgical aspects of dispersion nitride hardening of high-carbon steel. Message 1. The effect of austenizing heating and tempering parameters on the phase redistribution of nitrogen and vanadium in steels","authors":"S. Shypytsyn, E. Isaeva, D. Lykhovey, T. Stepanova, N. Kiryakova","doi":"10.15407/mom2023.04.058","DOIUrl":"https://doi.org/10.15407/mom2023.04.058","url":null,"abstract":"Systemic fundamental research for several decades at the FTIMS of the National Academy of Sciences of Ukraine and the accumulated experience of industrial application have shown that the technology of dispersion nitride hardening, which is based on the alloying of steels with nitrogen and vanadium, is a method of significantly improving the entire complex of physical, mechanical and operational properties of cast and deformed carbon, low-alloy and alloy steels of various functional purposes. The most significant advantage of the steels developed at the FTIMS of the National Academy of Sciences of Ukraine is a simultaneous significant increase in their static and cyclic strength, fracture toughness, thermal strength and heat resistance, wear resistance, annealing, weldability, reduction or complete elimination of the tendency to natural, deformation and warm embrittlement. Medium- and high-carbon pre-eutectoid and eutectoid steels of high strength and wear resistance are widely used in various fields of mechanical engineering. However, they are most widely used for railway wheels and rails. The reliability and operational resource of wheels and rails, which are in extremely harsh operating conditions, mainly determine the technical and economic performance indicators of railway transport. At the same time, existing relatively cheap non-alloyed and low-alloyed medium- and high-carbon wheel and rail steels no longer meet the modern requirements of increased speeds and load capacity of rolling stock. Keywords: carbon steels, dispersion nitride hardening, austenization, tempering, phase redistribution of nitrogen and vanadium.","PeriodicalId":508191,"journal":{"name":"Metaloznavstvo ta obrobka metalìv","volume":"152 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139183479","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}
According to the results of previous studies, it was found that the temperature dependence of electrical resistance during heating of the Al + 17,6 % Si melt curve characterized by presence of several sharp inflections. This gave grounds for asserting possibility of temperature-induced changes in structure of specified system melts. However, it remains an open question whether the changes that occurred when melt was overheated are preserved during subsequent cooling. The problem of effect of temperature-induced changes in Al–Si melts structure on the structure and properties of the alloy in the solid state also requires a more detailed study. Resistometric studies of melt were carried out according to the method [1]. The ability to preserve temperature-induced changes in melt was assessed by electrical resistance value during cooling of the overheated Al + 17,6 % Si melt at five characteristic temperature values. To avoid errors cozied by imbalance, only results obtained after stabilization of melt resistance at a given temperature were taken into account. Temperature-induced changes in melt structure were evaluated by structure of solid samples obtained by quenching from the liquid state. The nature of influence of changes that occur when the melt is overheated on solid alloy structure and properties was determined by specific electrical resistance values and material microstructures of samples obtained after melt isothermal holding at temperatures of 720 °C, 880 °C, 960 °C and 1050 °C. The presence of electric resistance significant hysteresis can indicate that the changes that occurred during melt overheating are preserved during its cooling. It was also established that the specified changes affect to properties (in particular, specific electrical resistance) and the microstructure of the solid alloy (first of all, the melt overheating affects to size of primary silicon particles). Keywords: aluminum, silicon, thermodynamic equilibrium, melts, electrical resistance.
根据之前的研究结果，发现在加热 Al + 17.6 % Si 熔体的过程中，电阻的温度依赖性曲线的特点是存在几个急转弯。这为断言特定系统熔体的结构可能因温度而发生变化提供了依据。然而，熔体过热时发生的变化是否会在随后的冷却过程中保留下来，这仍然是一个未决问题。温度引起的铝硅熔体结构变化对合金固态结构和性能的影响问题也需要更详细的研究。根据 [1] 方法对熔体进行了电阻测量研究。在五个特征温度值下冷却过热的铝+17.6%硅熔体时，通过电阻值来评估熔体保持温度引起的变化的能力。为避免不平衡造成的误差，只考虑在给定温度下熔体电阻稳定后获得的结果。温度引起的熔体结构变化是通过从液态淬火得到的固态样品的结构进行评估的。在 720 ℃、880 ℃、960 ℃ 和 1050 ℃ 温度下进行熔体等温保温后获得的样品的特定电阻值和材料微观结构确定了熔体过热时发生的变化对固体合金结构和性能的影响性质。电阻明显滞后现象的存在表明，熔体过热时发生的变化在冷却过程中得以保留。研究还证实，特定的变化会影响固态合金的特性（尤其是比电阻）和微观结构（首先，熔体过热会影响原生硅颗粒的大小）。关键词：铝、硅、热力学平衡、熔体、电阻。
{"title":"Influence of temperature-induced changes in Al – Si system melt structure on structure and electrical resistance of alloy in solid state","authors":"V. V. Khristenko, M. V. Arshuk, O. M. Donii","doi":"10.15407/mom2023.04.014","DOIUrl":"https://doi.org/10.15407/mom2023.04.014","url":null,"abstract":"According to the results of previous studies, it was found that the temperature dependence of electrical resistance during heating of the Al + 17,6 % Si melt curve characterized by presence of several sharp inflections. This gave grounds for asserting possibility of temperature-induced changes in structure of specified system melts. However, it remains an open question whether the changes that occurred when melt was overheated are preserved during subsequent cooling. The problem of effect of temperature-induced changes in Al–Si melts structure on the structure and properties of the alloy in the solid state also requires a more detailed study. Resistometric studies of melt were carried out according to the method [1]. The ability to preserve temperature-induced changes in melt was assessed by electrical resistance value during cooling of the overheated Al + 17,6 % Si melt at five characteristic temperature values. To avoid errors cozied by imbalance, only results obtained after stabilization of melt resistance at a given temperature were taken into account. Temperature-induced changes in melt structure were evaluated by structure of solid samples obtained by quenching from the liquid state. The nature of influence of changes that occur when the melt is overheated on solid alloy structure and properties was determined by specific electrical resistance values and material microstructures of samples obtained after melt isothermal holding at temperatures of 720 °C, 880 °C, 960 °C and 1050 °C. The presence of electric resistance significant hysteresis can indicate that the changes that occurred during melt overheating are preserved during its cooling. It was also established that the specified changes affect to properties (in particular, specific electrical resistance) and the microstructure of the solid alloy (first of all, the melt overheating affects to size of primary silicon particles). Keywords: aluminum, silicon, thermodynamic equilibrium, melts, electrical resistance.","PeriodicalId":508191,"journal":{"name":"Metaloznavstvo ta obrobka metalìv","volume":"312 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139183260","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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