Pub Date : 2022-03-15DOI: 10.17212/1994-6309-2022-24.1-73-86
S. Vologzhanina, A. Igolkin, A. Peregudov, I. Baranov, N. Martyushev
Introduction. For reliable operation of low-temperature equipment, it is necessary to use materials capable of ensuring operability in a wide temperature range under conditions of alternating loads, exposure to corrosive media, etc. Most often, in such cases, metastable austenitic steels (MAS) of various alloying systems are used. Despite sufficient experience in the use of such materials, not enough information is collected on the behavior of such materials at low temperatures, including phase-structural transformations, the features of such transformations in different temperature zones, including when a load is applied, both static and dynamic. The subject of the study in this work is selected MAS 10Cr14NMn20 and 10Cr14Mn14Ni4Ti grades. The purpose of the study is to evaluate the performance of industrially used metastable austenitic steels for its possible use instead of steel 12Cr18Ni10Ti. Research methodology. The phase composition of the samples was studied on a DRON-3.0 X-ray diffractometer. Mechanical tests were carried out in the temperature range from +20 to -196 °C. Static uniaxial tensile tests were carried out on a R-20 tensile testing machine; cylindrical specimens with threaded heads were prepared according to GOST 11150–75, as well as samples with a circumferential notches. Dynamic bending tests were carried out on a pendulum impact tester, using samples according to GOST 9454–78. Results and Discussion. Based on the data obtained, it is found that an increase in the strain rate at low temperatures contributes to a decrease in the number of martensitic phases in the steels under study. It is found that the hardenability during elastic-plastic deformation decreases and completely disappears at the temperature of the material transition to a brittle state. It is shown that an increase in the rate of low-temperature deformation of samples prevents the development of phase martensitic transformations in steels. The results obtained can be recommended for use in the selection of materials for the manufacture of equipment operating at temperatures down to -196 °C. Conclusions. It is shown that the obtained values of the characteristics of mechanical properties make it possible to recommend the studied MAS as a substitute for steel 12Cr18Ni10Ti, down to a temperature of -196 °C.
{"title":"Effect of the deformation degree at low temperatures on the phase transformations and properties of metastable austenitic steels","authors":"S. Vologzhanina, A. Igolkin, A. Peregudov, I. Baranov, N. Martyushev","doi":"10.17212/1994-6309-2022-24.1-73-86","DOIUrl":"https://doi.org/10.17212/1994-6309-2022-24.1-73-86","url":null,"abstract":"Introduction. For reliable operation of low-temperature equipment, it is necessary to use materials capable of ensuring operability in a wide temperature range under conditions of alternating loads, exposure to corrosive media, etc. Most often, in such cases, metastable austenitic steels (MAS) of various alloying systems are used. Despite sufficient experience in the use of such materials, not enough information is collected on the behavior of such materials at low temperatures, including phase-structural transformations, the features of such transformations in different temperature zones, including when a load is applied, both static and dynamic. The subject of the study in this work is selected MAS 10Cr14NMn20 and 10Cr14Mn14Ni4Ti grades. The purpose of the study is to evaluate the performance of industrially used metastable austenitic steels for its possible use instead of steel 12Cr18Ni10Ti. Research methodology. The phase composition of the samples was studied on a DRON-3.0 X-ray diffractometer. Mechanical tests were carried out in the temperature range from +20 to -196 °C. Static uniaxial tensile tests were carried out on a R-20 tensile testing machine; cylindrical specimens with threaded heads were prepared according to GOST 11150–75, as well as samples with a circumferential notches. Dynamic bending tests were carried out on a pendulum impact tester, using samples according to GOST 9454–78. Results and Discussion. Based on the data obtained, it is found that an increase in the strain rate at low temperatures contributes to a decrease in the number of martensitic phases in the steels under study. It is found that the hardenability during elastic-plastic deformation decreases and completely disappears at the temperature of the material transition to a brittle state. It is shown that an increase in the rate of low-temperature deformation of samples prevents the development of phase martensitic transformations in steels. The results obtained can be recommended for use in the selection of materials for the manufacture of equipment operating at temperatures down to -196 °C. Conclusions. It is shown that the obtained values of the characteristics of mechanical properties make it possible to recommend the studied MAS as a substitute for steel 12Cr18Ni10Ti, down to a temperature of -196 °C.","PeriodicalId":42889,"journal":{"name":"Obrabotka Metallov-Metal Working and Material Science","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45927069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-15DOI: 10.17212/1994-6309-2022-24.1-48-60
A. Ozolin, E. Sokolov
Introduction. One of the methods for improving the properties of sintered materials is mechanical activation of powders. It ensures milling the powders, changing its energy state, intensifying the sintering of powder materials, and forming a fine-grained structure in it. When tungsten powders are mechanically activated in planetary centrifugal mills, nanoparticles can be formed, which have a high reactive power. The objective of the paper is to study the effect of mechanical activation of tungsten particles on the structure and properties of the sintered Sn-Cu-Co-W powder material. Research technique: Mechanical activation of W16,5 grade tungsten powder is carried out in a planetary centrifugal ball mill AGO-2U for 5…120 minutes with carrier speeds of 400…1,000 rpm. The mixture of tungsten, tin, copper, and cobalt powders are compacted by static pressing in molds and then sintered in vacuum at 820 °C. The morphology and size of powder particles, as well as the structure of the sintered samples, are studied by scanning electronic microscopy, X-ray microanalysis, and optical metallography. Porosity of the sintered samples is identified by the gravimetric method. Microhardness of the structural constituents and macrohardness of the sintered materials are measured, too. Results: in the modes under study, mechanical activation is accompanied by the formation of tungsten nanoparticles with the minimum size of 25 nm. Alongside this, the powder is exposed to cold working, which hinders further milling. Tungsten nanoparticles, characterized by high surface energy, have a significant effect on the dissolution-precipitation of cobalt during liquid-phase sintering of Sn-Cu-Co-W powder material. Addition of nanodispersed tungsten into the material slows down the growth of cobalt particles during sintering and contributes to the formation of a fine-grained structure. The sintered Sn-Cu-Co-W material, containing mechanically activated tungsten, features higher hardness of 105…107 HRB, which is explained by cold working of tungsten particles and dispersion hardening. The results can be applied for improving mechanical properties of Sn-Cu-Co-W alloys used as metallic binders in diamond abrasive tools.
{"title":"Effect of mechanical activation of tungsten powder on the structure and properties of the sintered Sn-Cu-Co-W material","authors":"A. Ozolin, E. Sokolov","doi":"10.17212/1994-6309-2022-24.1-48-60","DOIUrl":"https://doi.org/10.17212/1994-6309-2022-24.1-48-60","url":null,"abstract":"Introduction. One of the methods for improving the properties of sintered materials is mechanical activation of powders. It ensures milling the powders, changing its energy state, intensifying the sintering of powder materials, and forming a fine-grained structure in it. When tungsten powders are mechanically activated in planetary centrifugal mills, nanoparticles can be formed, which have a high reactive power. The objective of the paper is to study the effect of mechanical activation of tungsten particles on the structure and properties of the sintered Sn-Cu-Co-W powder material. Research technique: Mechanical activation of W16,5 grade tungsten powder is carried out in a planetary centrifugal ball mill AGO-2U for 5…120 minutes with carrier speeds of 400…1,000 rpm. The mixture of tungsten, tin, copper, and cobalt powders are compacted by static pressing in molds and then sintered in vacuum at 820 °C. The morphology and size of powder particles, as well as the structure of the sintered samples, are studied by scanning electronic microscopy, X-ray microanalysis, and optical metallography. Porosity of the sintered samples is identified by the gravimetric method. Microhardness of the structural constituents and macrohardness of the sintered materials are measured, too. Results: in the modes under study, mechanical activation is accompanied by the formation of tungsten nanoparticles with the minimum size of 25 nm. Alongside this, the powder is exposed to cold working, which hinders further milling. Tungsten nanoparticles, characterized by high surface energy, have a significant effect on the dissolution-precipitation of cobalt during liquid-phase sintering of Sn-Cu-Co-W powder material. Addition of nanodispersed tungsten into the material slows down the growth of cobalt particles during sintering and contributes to the formation of a fine-grained structure. The sintered Sn-Cu-Co-W material, containing mechanically activated tungsten, features higher hardness of 105…107 HRB, which is explained by cold working of tungsten particles and dispersion hardening. The results can be applied for improving mechanical properties of Sn-Cu-Co-W alloys used as metallic binders in diamond abrasive tools.","PeriodicalId":42889,"journal":{"name":"Obrabotka Metallov-Metal Working and Material Science","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44438998","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-15DOI: 10.17212/1994-6309-2022-24.1-33-47
S. Bratan, S. Roshchupkin, A. Chasovitina, K. Gupta
Introduction. Grinding remains the most efficient and effective method of final finishing that is indispensable in the production of high-precision parts. The characteristic features of grinding materials are that the removal of the material roughness of the workpiece surface occurs due to the stochastic interaction of the grains of the abrasive material with the surface of the workpiece, in the presence of mutual oscillatory movements of the abrasive tool and the workpiece being processed. During processing workpieces with abrasive tools, the material is removed by a large number of grains that do not have a regular geometry and are randomly located on the working surface. This makes it necessary to apply probability theory and the theory of random processes in mathematical simulation of operations. In real conditions, during grinding, the contact of the wheel with the workpiece is carried out with a periodically changing depth due to machine vibrations, tool shape deviations from roundness, unbalance of the wheel or insufficient rigidity of the workpiece. To eliminate the influence of vibrations in production, tools with soft ligaments are used, the value of longitudinal and transverse feeds is reduced, but all these measures lead to a decrease in the operation efficiency, which is extremely undesirable. To avoid cost losses, mathematical models are needed that adequately describe the process, taking into account the influence of vibrations on the output indicators of the grinding process. The purpose of the work is to create a theoretical and probabilistic model of material removing during finishing and fine grinding, which allows, taking into account the relative vibrations of the abrasive tool and the workpiece, to trace the patterns of its removal in the contact zone. The research methods are mathematical and physical simulation using the basic provisions of probability theory, the laws of distribution of random variables, as well as the theory of cutting and the theory of deformable solids. Results and discussion. The developed mathematical models allow tracing the effect on the removal of the material of the superimposition of single sections on each other during the final grinding of materials. The proposed dependencies show the regularity of the stock removal within the arc of contact of the grinding wheel with the workpiece. The considered features of the change in the probability of material removal when the treated surface comes into contact with an abrasive tool in the presence of vibrations, the proposed analytical dependences are valid for a wide range of grinding modes, wheel characteristics and a number of other technological factors. The expressions obtained allow finding the amount of material removal also for the schemes of end, profile, flat and round external and internal grinding, for which it is necessary to know the magnitude of relative vibrations. However, the parameters of the technological system do not remain consta
{"title":"The effect of the relative vibrations of the abrasive tool and the workpiece on the probability of material removing during finishing grinding","authors":"S. Bratan, S. Roshchupkin, A. Chasovitina, K. Gupta","doi":"10.17212/1994-6309-2022-24.1-33-47","DOIUrl":"https://doi.org/10.17212/1994-6309-2022-24.1-33-47","url":null,"abstract":"Introduction. Grinding remains the most efficient and effective method of final finishing that is indispensable in the production of high-precision parts. The characteristic features of grinding materials are that the removal of the material roughness of the workpiece surface occurs due to the stochastic interaction of the grains of the abrasive material with the surface of the workpiece, in the presence of mutual oscillatory movements of the abrasive tool and the workpiece being processed. During processing workpieces with abrasive tools, the material is removed by a large number of grains that do not have a regular geometry and are randomly located on the working surface. This makes it necessary to apply probability theory and the theory of random processes in mathematical simulation of operations. In real conditions, during grinding, the contact of the wheel with the workpiece is carried out with a periodically changing depth due to machine vibrations, tool shape deviations from roundness, unbalance of the wheel or insufficient rigidity of the workpiece. To eliminate the influence of vibrations in production, tools with soft ligaments are used, the value of longitudinal and transverse feeds is reduced, but all these measures lead to a decrease in the operation efficiency, which is extremely undesirable. To avoid cost losses, mathematical models are needed that adequately describe the process, taking into account the influence of vibrations on the output indicators of the grinding process. The purpose of the work is to create a theoretical and probabilistic model of material removing during finishing and fine grinding, which allows, taking into account the relative vibrations of the abrasive tool and the workpiece, to trace the patterns of its removal in the contact zone. The research methods are mathematical and physical simulation using the basic provisions of probability theory, the laws of distribution of random variables, as well as the theory of cutting and the theory of deformable solids. Results and discussion. The developed mathematical models allow tracing the effect on the removal of the material of the superimposition of single sections on each other during the final grinding of materials. The proposed dependencies show the regularity of the stock removal within the arc of contact of the grinding wheel with the workpiece. The considered features of the change in the probability of material removal when the treated surface comes into contact with an abrasive tool in the presence of vibrations, the proposed analytical dependences are valid for a wide range of grinding modes, wheel characteristics and a number of other technological factors. The expressions obtained allow finding the amount of material removal also for the schemes of end, profile, flat and round external and internal grinding, for which it is necessary to know the magnitude of relative vibrations. However, the parameters of the technological system do not remain consta","PeriodicalId":42889,"journal":{"name":"Obrabotka Metallov-Metal Working and Material Science","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47935207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-15DOI: 10.17212/1994-6309-2022-24.1-87-102
A. Filippov, N. Shamarin, E. Moskvichev, O. Novitskaya, Evgenii Knyazhev, Yu. I. Denisova, A. Leonov, V. Denisov
Introduction. Modern technologies allow the synthesis of nanostructured coatings from multiple chemical elements to combine different physical, mechanical, and chemical properties in one coating. Promising in this respect are coatings formed via layer-by-layer deposition of zirconium and chromium nitrides. The deposition of various chemical elements on various substrates requires separate studies in order to produce high-strength and wear-resistant coatings. The purpose of this work is to study the structural-phase state and mechanical properties of ZrCrN coatings formed by plasma-assisted vacuum arc evaporation. Materials and methods. The investigation is performed on specimens comprising VK8 hard alloy substrates with zirconium and chromium nitride coatings as well as with multilayer ZrCrN coatings. The methods used are confocal laser scanning microscopy, X-ray diffraction analysis, high-resolution scanning electron microscopy, nanoindentation, and scratching. Results and discussion. The experimental results obtained showed that the mode of multilayer ZrCrN coating evaporation greatly affects the structure, morphology, surface roughness, and mechanical properties of the coatings. In particular, by varying the substrate rotation speed during coating deposition it is possible to control the deposition time of each coating layer and thereby modify the layer properties. Conclusions. The investigation results showed that variation of the evaporation conditions allows one to obtain a ZrCrN coating with a high nanohardness of 45 GPa on a VK8 alloy substrate. Analysis of mechanical test results indicate good adhesion between the studied coatings and the substrate. Scratch tests revealed that fracture of CrN and ZrN coatings occurs by the cohesive mechanism, and the surface of ZrCrN coatings exhibits uniform scratches without any signs of fracture. Based on the results obtained, ZrCrN-2…ZrCrN-4 coatings can be recommended for use as hard and wear-resistant coatings.
{"title":"Investigation of the structural-phase state and mechanical properties of ZrCrN coatings obtained by plasma-assisted vacuum arc evaporation","authors":"A. Filippov, N. Shamarin, E. Moskvichev, O. Novitskaya, Evgenii Knyazhev, Yu. I. Denisova, A. Leonov, V. Denisov","doi":"10.17212/1994-6309-2022-24.1-87-102","DOIUrl":"https://doi.org/10.17212/1994-6309-2022-24.1-87-102","url":null,"abstract":"Introduction. Modern technologies allow the synthesis of nanostructured coatings from multiple chemical elements to combine different physical, mechanical, and chemical properties in one coating. Promising in this respect are coatings formed via layer-by-layer deposition of zirconium and chromium nitrides. The deposition of various chemical elements on various substrates requires separate studies in order to produce high-strength and wear-resistant coatings. The purpose of this work is to study the structural-phase state and mechanical properties of ZrCrN coatings formed by plasma-assisted vacuum arc evaporation. Materials and methods. The investigation is performed on specimens comprising VK8 hard alloy substrates with zirconium and chromium nitride coatings as well as with multilayer ZrCrN coatings. The methods used are confocal laser scanning microscopy, X-ray diffraction analysis, high-resolution scanning electron microscopy, nanoindentation, and scratching. Results and discussion. The experimental results obtained showed that the mode of multilayer ZrCrN coating evaporation greatly affects the structure, morphology, surface roughness, and mechanical properties of the coatings. In particular, by varying the substrate rotation speed during coating deposition it is possible to control the deposition time of each coating layer and thereby modify the layer properties. Conclusions. The investigation results showed that variation of the evaporation conditions allows one to obtain a ZrCrN coating with a high nanohardness of 45 GPa on a VK8 alloy substrate. Analysis of mechanical test results indicate good adhesion between the studied coatings and the substrate. Scratch tests revealed that fracture of CrN and ZrN coatings occurs by the cohesive mechanism, and the surface of ZrCrN coatings exhibits uniform scratches without any signs of fracture. Based on the results obtained, ZrCrN-2…ZrCrN-4 coatings can be recommended for use as hard and wear-resistant coatings.","PeriodicalId":42889,"journal":{"name":"Obrabotka Metallov-Metal Working and Material Science","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42933685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-15DOI: 10.17212/1994-6309-2022-24.1-6-22
V. Kuznetsov, A. Makarov, A. Skorobogatov, P. Skorynina, S. Luchko, V. Sirosh, N. Chekan
Introduction. Sliding burnishing minimizes roughness and hardens of the steel surface. Quality of the formed surface and strength characteristics of the surface layer are determined by the burnishing speed, force and feed. Due to the danger of the surface micro-destruction during burnishing, the problem of selecting the favorable value of the normal force at a given feed arises. The current investigation aims to study the effect of normal force during dry diamond burnishing with a spherical indenter on smoothing the surface microprofile and strain hardening of the 03Cr16Ni15Mo3Ti1 austenitic steel surface layer. Research methods. Profilometry, scanning electron microscopy (SEM), microdurometry are used. Results and discussion. As the result of dry burnishing of deformation-stable austenitic steel 03Cr16Ni15Mo3Ti1 with a spherical indenter with a 2 mm radius made of natural diamond at a sliding speed of 10 m/min and feed rate of 0.025 mm/rev, it is found that in the investigated variation range of the burnishing normal force (100...200 N) the value of the smoothing coefficient of the initial steel surface microprofile after finish turning is 79...90 %, the greatest smoothing with a decrease in the average roughness parameter Ra from 1.0 to 0.1 µm is achieved at a force of 150 N; during diamond burnishing the initial (after finish turning) surface is hardened by 15...43 % (up to 382...444 HV), as the burnishing force raises from 100 to 175 N, a non-monotonic increase of the average microhardness from 409 to 444 HV 0.05 takes place; burnishing with a load of 175 N forms a gradient-hardened layer with a thickness of 300...350 μm with the appearance of individual microfractures in the form of beadings and micro-cracks on the surface, the maximum hardening is caused by the formation of a highly dispersed surface layer of 30...40 μm thick with a structure of highly dispersed austenite and the corresponding activation of grain-boundary and dislocation strengthening mechanisms. The results can be used when selecting the diamond burnishing parameters of parts made of corrosion-resistant austenitic steels according to the criteria for obtaining low surface roughness without significant microfractures and effective strain hardening of the surface layer.
{"title":"Normal force influence on smoothing and hardening of steel 03Cr16Ni15Mo3Ti1 surface layer during dry diamond burnishing with spherical indenter","authors":"V. Kuznetsov, A. Makarov, A. Skorobogatov, P. Skorynina, S. Luchko, V. Sirosh, N. Chekan","doi":"10.17212/1994-6309-2022-24.1-6-22","DOIUrl":"https://doi.org/10.17212/1994-6309-2022-24.1-6-22","url":null,"abstract":"Introduction. Sliding burnishing minimizes roughness and hardens of the steel surface. Quality of the formed surface and strength characteristics of the surface layer are determined by the burnishing speed, force and feed. Due to the danger of the surface micro-destruction during burnishing, the problem of selecting the favorable value of the normal force at a given feed arises. The current investigation aims to study the effect of normal force during dry diamond burnishing with a spherical indenter on smoothing the surface microprofile and strain hardening of the 03Cr16Ni15Mo3Ti1 austenitic steel surface layer. Research methods. Profilometry, scanning electron microscopy (SEM), microdurometry are used. Results and discussion. As the result of dry burnishing of deformation-stable austenitic steel 03Cr16Ni15Mo3Ti1 with a spherical indenter with a 2 mm radius made of natural diamond at a sliding speed of 10 m/min and feed rate of 0.025 mm/rev, it is found that in the investigated variation range of the burnishing normal force (100...200 N) the value of the smoothing coefficient of the initial steel surface microprofile after finish turning is 79...90 %, the greatest smoothing with a decrease in the average roughness parameter Ra from 1.0 to 0.1 µm is achieved at a force of 150 N; during diamond burnishing the initial (after finish turning) surface is hardened by 15...43 % (up to 382...444 HV), as the burnishing force raises from 100 to 175 N, a non-monotonic increase of the average microhardness from 409 to 444 HV 0.05 takes place; burnishing with a load of 175 N forms a gradient-hardened layer with a thickness of 300...350 μm with the appearance of individual microfractures in the form of beadings and micro-cracks on the surface, the maximum hardening is caused by the formation of a highly dispersed surface layer of 30...40 μm thick with a structure of highly dispersed austenite and the corresponding activation of grain-boundary and dislocation strengthening mechanisms. The results can be used when selecting the diamond burnishing parameters of parts made of corrosion-resistant austenitic steels according to the criteria for obtaining low surface roughness without significant microfractures and effective strain hardening of the surface layer.","PeriodicalId":42889,"journal":{"name":"Obrabotka Metallov-Metal Working and Material Science","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45752474","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 : 2021-12-13DOI: 10.17212/1994-6309-2021-23.4-111-124
V. Fedorov, A. Rygin, V. Klimenov, N. Martyushev, A. Klopotov, I. Strelkova, S. Matrenin, A. Batranin, Valentina Deryusheva
Introduction. As of today, additive technologies are among the most promising methods to manufacture various parts. They allow producing parts of complex shapes and provide their quality structure. The quality of the structure formed depends on numerous parameters: equipment type, its operation mode, materials, shielding medium, etc. Large international companies producing 3D-printers provide technological guidelines for working on it. Such guidelines include the information on the manufacturers of raw materials (printing powders), products their equipment can work with and the operation modes that should be used with such powders. These parameters should be investigated to use it on the domestic equipment developed within the framework of research programs and import substitution programs. The researchers and developers of 3D-printing equipment frequently run into a problem of using currently available raw materials for obtaining parts possessing minimal porosity, uniform structure and mechanical properties similar to that of at least cast blanks. One of the widely used materials for 3D-printing is stainless steel. It has high corrosion resistance, which reduces the requirements to the medium in which 3D printing is carried out. Manufactured stainless steel products have a good combination of strength and plastic characteristics. The aim of the study is to obtain stainless steel specimens possessing minimal number of micro- and macro-defects and uniform structure by the method of wire arc additive manufacturing using an electron-beam setup developed at Tomsk Polytechnic University. The methods to study the AISI 308LSi stainless steel 3D-printed specimens are as follows: XRD analysis, tomography, chemical analysis, metallographic analysis, microhardness testing. Results and discussion. It is established that the AISI 308LSi stainless steel specimens manufactured using the electron-beam 3D-printing setup contain no macro-defects in the bulk of the specimens. There are small microdefects represented by residual gas pores with the dimensions of no more than 5.2 μm. The microstructure of the specimens is formed close to that of coarse-grained cast austenite steels and consists of columnar grains of the γ-Fe austenite matrix and high-temperature ferrite. The interfaces between the wire layers are not pronounced; however, there are small differences in phase composition. Based on the analysis of the results obtained, it is established that the use of electron-beam 3D-printing for the manufacture of parts from AISI 308LSi steel gives a structure similar to cast austenitic steels. Macro-defects do not appear, and the number of gas pores is small.
{"title":"Structural and mechanical properties of stainless steel formed under conditions of layer-by-layer fusion of a wire by an electron beam","authors":"V. Fedorov, A. Rygin, V. Klimenov, N. Martyushev, A. Klopotov, I. Strelkova, S. Matrenin, A. Batranin, Valentina Deryusheva","doi":"10.17212/1994-6309-2021-23.4-111-124","DOIUrl":"https://doi.org/10.17212/1994-6309-2021-23.4-111-124","url":null,"abstract":"Introduction. As of today, additive technologies are among the most promising methods to manufacture various parts. They allow producing parts of complex shapes and provide their quality structure. The quality of the structure formed depends on numerous parameters: equipment type, its operation mode, materials, shielding medium, etc. Large international companies producing 3D-printers provide technological guidelines for working on it. Such guidelines include the information on the manufacturers of raw materials (printing powders), products their equipment can work with and the operation modes that should be used with such powders. These parameters should be investigated to use it on the domestic equipment developed within the framework of research programs and import substitution programs. The researchers and developers of 3D-printing equipment frequently run into a problem of using currently available raw materials for obtaining parts possessing minimal porosity, uniform structure and mechanical properties similar to that of at least cast blanks. One of the widely used materials for 3D-printing is stainless steel. It has high corrosion resistance, which reduces the requirements to the medium in which 3D printing is carried out. Manufactured stainless steel products have a good combination of strength and plastic characteristics. The aim of the study is to obtain stainless steel specimens possessing minimal number of micro- and macro-defects and uniform structure by the method of wire arc additive manufacturing using an electron-beam setup developed at Tomsk Polytechnic University. The methods to study the AISI 308LSi stainless steel 3D-printed specimens are as follows: XRD analysis, tomography, chemical analysis, metallographic analysis, microhardness testing. Results and discussion. It is established that the AISI 308LSi stainless steel specimens manufactured using the electron-beam 3D-printing setup contain no macro-defects in the bulk of the specimens. There are small microdefects represented by residual gas pores with the dimensions of no more than 5.2 μm. The microstructure of the specimens is formed close to that of coarse-grained cast austenite steels and consists of columnar grains of the γ-Fe austenite matrix and high-temperature ferrite. The interfaces between the wire layers are not pronounced; however, there are small differences in phase composition. Based on the analysis of the results obtained, it is established that the use of electron-beam 3D-printing for the manufacture of parts from AISI 308LSi steel gives a structure similar to cast austenitic steels. Macro-defects do not appear, and the number of gas pores is small.","PeriodicalId":42889,"journal":{"name":"Obrabotka Metallov-Metal Working and Material Science","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2021-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42591692","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 : 2021-12-13DOI: 10.17212/1994-6309-2021-23.4-33-46
Dmitry Buzaev, N. Zubkov
Introduction. Slot filters are in demand in petrochemical, machine-building, food, mining and other industries. DC is an edge cutting machining method based on undercutting and plastic deformation of the workpiece’s surface layer without its removal in the form of chip. DC stands out from the other slot structure forming methods for its capability of obtaining fine filters (slot width upwards of 20 µm) while maintaining relatively high productivity rate and being waste-free. Nevertheless, patterns of through slots cutting by means of DC had virtually not been investigated previously. The purpose of the work is to establish the influence of the main parameters of deformational cutting, namely feed and depth of cut, on features of through slots obtained, as well as identifying combinations of parameters that ensure the production of structures suitable for filtration. Method of investigation consisted of experiments on through-cutting of corrugations stamped on copper strips and a visual analysis of the structures obtained. Cutting through the corrugations by DC was conducted on a lathe while using a special attachment – a barrel which workpiece corrugated strips were wrapped around and fixed on with tension. Results and discussion. The resulting typical structures obtained under different combinations of depth of cut and feed are systemized and divided into the following groups: “0” – the absence of the through cut; “1” – uniform slots; “2” – “twinning” (pairwise convergence of slot walls), “3” – stripping of every second slot wall; “4” – non-regular or complete stripping of slot walls; “5” – uniform slots with a continuous burr (“skirt”) formed along the slot row on the internal side of the corrugation; “6” – uniform slots with a “skirt” opened incompletely. In the range of feeds 0.2 ... 0.4 mm/rev with increasing cutting depth, there is a transition from structures of group “1” to structures of group “2”, and the greater the feed, the greater the maximum depth of cut, at which uniform slots remain. Group “1” is assigned to the area of structures suitable for filtration applications, although it is characterized by the formation of individual burrs on the inner side of each slot. At lower feeds (up to 0.2 mm/rev) with further increase of the depth of cut another group of structures potentially suitable for filtering purposes is reached: groups “5” and “6”. With the “skirt” formed, individual burrs next to each slots are absent, and the shape of slots is cleaner. With a decrease in feed, the width of the resulting slots decreases. The least tool feed value, at which uniform slots are obtained, is 0.05 mm/rev which corresponds to 19 µm slot width. Establishing the causes of “twinning” and the formation of “skirts” requires further investigation.
{"title":"Influence of the parameters of deforming cutting on the features of the resulting slotted filter structures","authors":"Dmitry Buzaev, N. Zubkov","doi":"10.17212/1994-6309-2021-23.4-33-46","DOIUrl":"https://doi.org/10.17212/1994-6309-2021-23.4-33-46","url":null,"abstract":"Introduction. Slot filters are in demand in petrochemical, machine-building, food, mining and other industries. DC is an edge cutting machining method based on undercutting and plastic deformation of the workpiece’s surface layer without its removal in the form of chip. DC stands out from the other slot structure forming methods for its capability of obtaining fine filters (slot width upwards of 20 µm) while maintaining relatively high productivity rate and being waste-free. Nevertheless, patterns of through slots cutting by means of DC had virtually not been investigated previously. The purpose of the work is to establish the influence of the main parameters of deformational cutting, namely feed and depth of cut, on features of through slots obtained, as well as identifying combinations of parameters that ensure the production of structures suitable for filtration. Method of investigation consisted of experiments on through-cutting of corrugations stamped on copper strips and a visual analysis of the structures obtained. Cutting through the corrugations by DC was conducted on a lathe while using a special attachment – a barrel which workpiece corrugated strips were wrapped around and fixed on with tension. Results and discussion. The resulting typical structures obtained under different combinations of depth of cut and feed are systemized and divided into the following groups: “0” – the absence of the through cut; “1” – uniform slots; “2” – “twinning” (pairwise convergence of slot walls), “3” – stripping of every second slot wall; “4” – non-regular or complete stripping of slot walls; “5” – uniform slots with a continuous burr (“skirt”) formed along the slot row on the internal side of the corrugation; “6” – uniform slots with a “skirt” opened incompletely. In the range of feeds 0.2 ... 0.4 mm/rev with increasing cutting depth, there is a transition from structures of group “1” to structures of group “2”, and the greater the feed, the greater the maximum depth of cut, at which uniform slots remain. Group “1” is assigned to the area of structures suitable for filtration applications, although it is characterized by the formation of individual burrs on the inner side of each slot. At lower feeds (up to 0.2 mm/rev) with further increase of the depth of cut another group of structures potentially suitable for filtering purposes is reached: groups “5” and “6”. With the “skirt” formed, individual burrs next to each slots are absent, and the shape of slots is cleaner. With a decrease in feed, the width of the resulting slots decreases. The least tool feed value, at which uniform slots are obtained, is 0.05 mm/rev which corresponds to 19 µm slot width. Establishing the causes of “twinning” and the formation of “skirts” requires further investigation.","PeriodicalId":42889,"journal":{"name":"Obrabotka Metallov-Metal Working and Material Science","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2021-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47179790","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 : 2021-12-13DOI: 10.17212/1994-6309-2021-23.4-93-110
R. Sokolov, V. Novikov, K. Muratov, Anatoli Z. Venediktov
Introduction: The control of the mechanical properties of structural steels is one of the main processes that regulate the service life of equipment. In most technical processes (pressure treatment, welding, rolling, thermal exposure), structure changes both in local areas and in the entire volume. Changes in the steel structure entail changes in its properties and as a result in local areas, at various stages of operation, the likelihood of the occurrence and development of critical defects increases. Its presence significantly affects the performance of the equipment, and leads to premature aging of the material and its failure. Precisely because the control of the mechanical properties of steel remains one of the urgent problems, new control methods are being developed. It is known that all properties of steel depend on the structure of the substance, however, studies on the effect of the dispersion of the structure under consideration on the mechanical properties are presented in an insignificant amount. Purpose: to analyze from a mathematical point of view the influence of the factor of different grain size, as a parameter reflecting the dispersity of the system, on the mechanical properties of structural steel. The paper studies a heat-treated planar samples of steels 15KhSND, 09G2S and St3. Methods of research: scanning electron and optical microscopes are used to study the grain structure and grain boundaries; SIAMS 700 software package is used for finding the boundaries and average data of the grain structure; portable X-ray fluorescence analyzer of metals and alloys X-MET 7000 is used to determine the chemical composition of the test samples in percentage; tensile testing machine IR-50 is used for measuring the tensile strength of samples; Vickers hardness tester is used to determine the hardness of samples. Results and discussion: it is found that there is a satisfactory correlation for the mechanical properties of structural steels (hardness and ultimate strength) and the grain size factor, which can be used to predict the hazardous states of structures and the operating time. The analysis of variance and regression of the detected dependencies is carried out. It is noted that the dropout of some values from the general regression dependence can most likely be associated with a decrease in the value of internal stresses as a result of a decrease in the distortions of the crystal lattice of steel occurring during heat treatment. It should be noted that the processes occurring and the degree of its influence on the properties of the structural steels under consideration can be different due to the presence of different amounts of alloying elements in the composition of the studied steels.
{"title":"Assessment of the effect of the steels structure dispersion on its magnetic and mechanical properties","authors":"R. Sokolov, V. Novikov, K. Muratov, Anatoli Z. Venediktov","doi":"10.17212/1994-6309-2021-23.4-93-110","DOIUrl":"https://doi.org/10.17212/1994-6309-2021-23.4-93-110","url":null,"abstract":"Introduction: The control of the mechanical properties of structural steels is one of the main processes that regulate the service life of equipment. In most technical processes (pressure treatment, welding, rolling, thermal exposure), structure changes both in local areas and in the entire volume. Changes in the steel structure entail changes in its properties and as a result in local areas, at various stages of operation, the likelihood of the occurrence and development of critical defects increases. Its presence significantly affects the performance of the equipment, and leads to premature aging of the material and its failure. Precisely because the control of the mechanical properties of steel remains one of the urgent problems, new control methods are being developed. It is known that all properties of steel depend on the structure of the substance, however, studies on the effect of the dispersion of the structure under consideration on the mechanical properties are presented in an insignificant amount. Purpose: to analyze from a mathematical point of view the influence of the factor of different grain size, as a parameter reflecting the dispersity of the system, on the mechanical properties of structural steel. The paper studies a heat-treated planar samples of steels 15KhSND, 09G2S and St3. Methods of research: scanning electron and optical microscopes are used to study the grain structure and grain boundaries; SIAMS 700 software package is used for finding the boundaries and average data of the grain structure; portable X-ray fluorescence analyzer of metals and alloys X-MET 7000 is used to determine the chemical composition of the test samples in percentage; tensile testing machine IR-50 is used for measuring the tensile strength of samples; Vickers hardness tester is used to determine the hardness of samples. Results and discussion: it is found that there is a satisfactory correlation for the mechanical properties of structural steels (hardness and ultimate strength) and the grain size factor, which can be used to predict the hazardous states of structures and the operating time. The analysis of variance and regression of the detected dependencies is carried out. It is noted that the dropout of some values from the general regression dependence can most likely be associated with a decrease in the value of internal stresses as a result of a decrease in the distortions of the crystal lattice of steel occurring during heat treatment. It should be noted that the processes occurring and the degree of its influence on the properties of the structural steels under consideration can be different due to the presence of different amounts of alloying elements in the composition of the studied steels.","PeriodicalId":42889,"journal":{"name":"Obrabotka Metallov-Metal Working and Material Science","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2021-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48698189","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 : 2021-12-13DOI: 10.17212/1994-6309-2021-23.4-79-92
I. Efimovich, I. Zolotukhin
Introduction. The efficiency of the metalworking processes highly depends on the performance of the implemented cutting tools that can be increased by studying its stress-strain state and temperature fields. Existing stress analysis methods either have a low accuracy or are inapplicable for research during the operation of the tools made of materials with high mechanical properties. In addition, the study of temperature fields using known methods is difficult due to the small size of the cutting zone, high temperatures, and a heavy temperature gradient appearing during metal cutting. The purpose of this study is to develop new experimental methods for measuring the stress-strain and temperature fields in the cutting tool during its operation using laser interferometry. The methods include: obtaining interference fringe patterns using an interferometer with the original design, obtaining the tool deformation field during the cutting process by recording the changes in interference fringe patterns using a high-speed camera, processing fringe patterns with the separation of deformations caused by heating and cutting forces, and calculating temperature fields and stress distributions using mechanical properties and the coefficient of thermal expansion of the tool material. The advantages of the developed methods include: applicability under real operating conditions of the cutting tool, ability to study the non-stationary stress-strain state and temperatures during an operation, and achievement of a high spatial resolution and a small field of view for the investigated surface. Results and Discussion. The experimental study confirmed the efficiency of the methods. The results of the study included the fields of stresses and temperatures obtained during the orthogonal cutting of heat-resistant steel with a tool made of cemented tungsten carbide WC-8Co. The developed methods can be used to study the cutting tool efficiency at close to real conditions and in obtaining boundary conditions for the study stress-strain state of a workpiece material near the cutting zone.
{"title":"Study of the stress-strain and temperature fields in cutting tools using laser interferometry","authors":"I. Efimovich, I. Zolotukhin","doi":"10.17212/1994-6309-2021-23.4-79-92","DOIUrl":"https://doi.org/10.17212/1994-6309-2021-23.4-79-92","url":null,"abstract":"Introduction. The efficiency of the metalworking processes highly depends on the performance of the implemented cutting tools that can be increased by studying its stress-strain state and temperature fields. Existing stress analysis methods either have a low accuracy or are inapplicable for research during the operation of the tools made of materials with high mechanical properties. In addition, the study of temperature fields using known methods is difficult due to the small size of the cutting zone, high temperatures, and a heavy temperature gradient appearing during metal cutting. The purpose of this study is to develop new experimental methods for measuring the stress-strain and temperature fields in the cutting tool during its operation using laser interferometry. The methods include: obtaining interference fringe patterns using an interferometer with the original design, obtaining the tool deformation field during the cutting process by recording the changes in interference fringe patterns using a high-speed camera, processing fringe patterns with the separation of deformations caused by heating and cutting forces, and calculating temperature fields and stress distributions using mechanical properties and the coefficient of thermal expansion of the tool material. The advantages of the developed methods include: applicability under real operating conditions of the cutting tool, ability to study the non-stationary stress-strain state and temperatures during an operation, and achievement of a high spatial resolution and a small field of view for the investigated surface. Results and Discussion. The experimental study confirmed the efficiency of the methods. The results of the study included the fields of stresses and temperatures obtained during the orthogonal cutting of heat-resistant steel with a tool made of cemented tungsten carbide WC-8Co. The developed methods can be used to study the cutting tool efficiency at close to real conditions and in obtaining boundary conditions for the study stress-strain state of a workpiece material near the cutting zone.","PeriodicalId":42889,"journal":{"name":"Obrabotka Metallov-Metal Working and Material Science","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2021-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45920924","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 : 2021-12-13DOI: 10.17212/1994-6309-2021-23.4-155-166
Yuriy L. Krutskii, E. Maksimovskii, R. Petrov, O. Netskina, A. Ukhina, T. Krutskaya, T. Gudyma
Introduction. Titanium carbide and diboride are characterized by high values of hardness, chemical inertness and for this reason are widely used in modern technology. This paper provides information on the synthesis of titanium carbide and diboride by carbothermal and carbide-boron methods, respectively, on the use of titanium carbide as an abrasive and in the manufacture of tungsten-free hard alloys, carbide steels, wear-resistant coatings, as well as titanium diboride in the production of cutting tools and ceramics based on boron carbide The aim of this work is to study the processes of synthesis of highly dispersed powders of titanium carbide and diboride, which are promising for the manufacture of cutting tools, wear-resistant coatings, abrasives and ceramics. Research methods. Titanium oxide TiO2, nanofibrous carbon (NFC), and highly dispersed boron carbide were used as reagents for the synthesis of titanium carbide and diboride. Experiments to obtain titanium carbide were carried out in a resistance furnace, and titanium diboride in an induction furnace. X-ray studies of the phase composition of titanium carbide and diboride samples were carried out on an ARL X-TRA diffractometer (Thermo Electron SA). The determination of the content of titanium and impurities in the samples of titanium carbide and diboride was carried out by the X-ray spectral fluorescence method on an ARL-Advant'x analyzer. The total carbon content in the titanium carbide samples was determined on an S-144 device from LECO. The content of boron and other elements for titanium diboride samples was determined by inductively coupled plasma atomic emission spectrometry (ICP AES) on an IRIS Advantage spectrometer (Thermo Jarrell Ash Corporation). The surface morphology and particle sizes of the samples were studied using a Carl Zeiss Sigma scanning electron microscope (Carl Zeiss). The determination of the particle/aggregate size distribution was performed on a MicroSizer 201 laser analyzer (BA Instruments). Results. The paper proposes technological processes for obtaining highly dispersed powders of titanium carbide and diboride. The optimum synthesis temperature for titanium carbide is 2,000…2,100 oC, and for titanium diboride 1,600…1,700 oC. The content of the basic substance is at the level of 97.5…98.0 wt. %. Discussion. A possible mechanism for the formation of titanium carbide and diboride is proposed, which consists in the transfer of vapors of titanium oxides to the surface of solid carbon (synthesis of titanium carbide) and vapors of boron and titanium oxides to the surface of solid carbon (synthesis of titanium diboride). Due to the high purity and dispersion values, the resulting titanium carbide powder can be used as an abrasive material and for the manufacture of tungsten-free hard alloys, carbide steels, wear-resistant coatings, and titanium diboride powder can be used for the preparation of cutting tools and ceramics based on boron carbide.
{"title":"Synthesis of titanium carbide and titanium diboride for metal processing and ceramics production","authors":"Yuriy L. Krutskii, E. Maksimovskii, R. Petrov, O. Netskina, A. Ukhina, T. Krutskaya, T. Gudyma","doi":"10.17212/1994-6309-2021-23.4-155-166","DOIUrl":"https://doi.org/10.17212/1994-6309-2021-23.4-155-166","url":null,"abstract":"Introduction. Titanium carbide and diboride are characterized by high values of hardness, chemical inertness and for this reason are widely used in modern technology. This paper provides information on the synthesis of titanium carbide and diboride by carbothermal and carbide-boron methods, respectively, on the use of titanium carbide as an abrasive and in the manufacture of tungsten-free hard alloys, carbide steels, wear-resistant coatings, as well as titanium diboride in the production of cutting tools and ceramics based on boron carbide The aim of this work is to study the processes of synthesis of highly dispersed powders of titanium carbide and diboride, which are promising for the manufacture of cutting tools, wear-resistant coatings, abrasives and ceramics. Research methods. Titanium oxide TiO2, nanofibrous carbon (NFC), and highly dispersed boron carbide were used as reagents for the synthesis of titanium carbide and diboride. Experiments to obtain titanium carbide were carried out in a resistance furnace, and titanium diboride in an induction furnace. X-ray studies of the phase composition of titanium carbide and diboride samples were carried out on an ARL X-TRA diffractometer (Thermo Electron SA). The determination of the content of titanium and impurities in the samples of titanium carbide and diboride was carried out by the X-ray spectral fluorescence method on an ARL-Advant'x analyzer. The total carbon content in the titanium carbide samples was determined on an S-144 device from LECO. The content of boron and other elements for titanium diboride samples was determined by inductively coupled plasma atomic emission spectrometry (ICP AES) on an IRIS Advantage spectrometer (Thermo Jarrell Ash Corporation). The surface morphology and particle sizes of the samples were studied using a Carl Zeiss Sigma scanning electron microscope (Carl Zeiss). The determination of the particle/aggregate size distribution was performed on a MicroSizer 201 laser analyzer (BA Instruments). Results. The paper proposes technological processes for obtaining highly dispersed powders of titanium carbide and diboride. The optimum synthesis temperature for titanium carbide is 2,000…2,100 oC, and for titanium diboride 1,600…1,700 oC. The content of the basic substance is at the level of 97.5…98.0 wt. %. Discussion. A possible mechanism for the formation of titanium carbide and diboride is proposed, which consists in the transfer of vapors of titanium oxides to the surface of solid carbon (synthesis of titanium carbide) and vapors of boron and titanium oxides to the surface of solid carbon (synthesis of titanium diboride). Due to the high purity and dispersion values, the resulting titanium carbide powder can be used as an abrasive material and for the manufacture of tungsten-free hard alloys, carbide steels, wear-resistant coatings, and titanium diboride powder can be used for the preparation of cutting tools and ceramics based on boron carbide.","PeriodicalId":42889,"journal":{"name":"Obrabotka Metallov-Metal Working and Material Science","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2021-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48690386","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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