Pub Date : 2018-08-16DOI: 10.17073/0021-3438-2018-4-24-30
V. Stakhanov, A. Redkin, Y. Zaikov, A. Galashev
The paper presents a theoretical study conducted to investigate the effect that the chemical composition of electrolyte and its overheating have on the size of sideledge formed in an aluminum smelting bath. Three electrolyte compositions were chosen: (1) sodium cryolite with the cryolite ratio CR = 2,7; (2) cryolite CR = 2,7 + 5 wt.% CaF2; (3) cryolite CR = 2,7 + 5 wt.% CaF2 + 5 wt.% Al2О3. The electrolyte liquidus overheating temperatures were 5, 10, 15 and 20 °C. Calculations were performed using the finite element method. A simplified design of an aluminum cell was used with a prebaked anode. The temperature field was calculated using a mathematical model based on the Boussinesq approximation, which contains the Navier–Stokes equation as well as thermal conductivity and incompressibility equations. The key role of electrolyte overheating in sideledge formation was established. The resulting sideledge profile depends on the heat transfer coefficients and thermophysical properties of materials. The smallest sideledge thickness with the same electrolyte overheating was observed in cryolite composition 3, and the profiles of the formed sideledge for samples 1 and 2 were nearly the same. The thickness of the sideledge formed with a 5 degree overheating exceeded 7 cm and the difference in temperature between the sideledge in contact with electrolyte and the side block wall was 20–25 degrees. It was found that the virtually total disappearance of the sideledge occurs at electrolyte liquidus overheating by 20 degrees.
{"title":"INFLUENCE OF ELECTROLYTE COMPOSITION AND OVERHEATING ON THE SIDELEDGE IN THE ALUMINUM CELL","authors":"V. Stakhanov, A. Redkin, Y. Zaikov, A. Galashev","doi":"10.17073/0021-3438-2018-4-24-30","DOIUrl":"https://doi.org/10.17073/0021-3438-2018-4-24-30","url":null,"abstract":"The paper presents a theoretical study conducted to investigate the effect that the chemical composition of electrolyte and its overheating have on the size of sideledge formed in an aluminum smelting bath. Three electrolyte compositions were chosen: (1) sodium cryolite with the cryolite ratio CR = 2,7; (2) cryolite CR = 2,7 + 5 wt.% CaF2; (3) cryolite CR = 2,7 + 5 wt.% CaF2 + 5 wt.% Al2О3. The electrolyte liquidus overheating temperatures were 5, 10, 15 and 20 °C. Calculations were performed using the finite element method. A simplified design of an aluminum cell was used with a prebaked anode. The temperature field was calculated using a mathematical model based on the Boussinesq approximation, which contains the Navier–Stokes equation as well as thermal conductivity and incompressibility equations. The key role of electrolyte overheating in sideledge formation was established. The resulting sideledge profile depends on the heat transfer coefficients and thermophysical properties of materials. The smallest sideledge thickness with the same electrolyte overheating was observed in cryolite composition 3, and the profiles of the formed sideledge for samples 1 and 2 were nearly the same. The thickness of the sideledge formed with a 5 degree overheating exceeded 7 cm and the difference in temperature between the sideledge in contact with electrolyte and the side block wall was 20–25 degrees. It was found that the virtually total disappearance of the sideledge occurs at electrolyte liquidus overheating by 20 degrees.","PeriodicalId":14523,"journal":{"name":"Izvestiya Vuzov Tsvetnaya Metallurgiya (Proceedings of Higher Schools Nonferrous Metallurgy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83556503","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 : 2018-08-16DOI: 10.17073/0021-3438-2018-4-53-59
Yu. V. Gorokhov, V. Timofeev, S. V. Belуaev, I. V. Uskov, I. Y. Gubanov, I. S. Gudkov
It is known that casting long ingots of small sections (∅8–12 mm) of 01417 alloy into an electromagnetic crystallizer makes it possible to obtain a dispersed structure with insignificant intradendritic segregation. Diffusion annealing of ingots (550 °C, 4–5 h holding time) eliminates intracrystalline segregation and reduces the level of internal stresses in metal thus providing the conditions for subsequent wire drawing. The paper demonstrates that high plastic deformation of ingots without diffusion annealing can be achieved by Conform continuous extrusion, which ensures high quality and geometrical accuracy of products. The analysis of various Conform units revealed an inherent weakness – the absence of connection between the system securing the fixed part of the detachable container (shoe) and the drive wheel shaft, which leads to an increased load in the operating mode. The purpose of the work was to upgrade the Conform unit by creating a connection between the shoe and the impeller shaft to obtain a high-quality billet for subsequent wire drawing of the ∅12 mm ingot cast into the electromagnetic crystallizer. An optimal temperature of ingot extrusion (300 °С) was found to eliminate the intense adhesion of wrought metal on the tool surface. The experimental ∅5 mm rod made of 01417 alloy obtained from the ∅12 mm ingot at the Conform unit features high processing ductility. This is indicated by an increase in its yield point and relative elongation. Metallographic studies demonstrated a fine-grained structure achieved in the extruded rod, which provides the conditions for subsequent wire drawing without annealing. The results of the study provide a basis for refining the process conditions of calibrated billet production on the Conform unit followed by wire drawing with required properties.
{"title":"EXTRUSION OF 01417 ALLOY INGOTS OBTAINED IN THE ELECTROMAGNETIC CRYSTALLIZER AT THE CONFORM UNIT","authors":"Yu. V. Gorokhov, V. Timofeev, S. V. Belуaev, I. V. Uskov, I. Y. Gubanov, I. S. Gudkov","doi":"10.17073/0021-3438-2018-4-53-59","DOIUrl":"https://doi.org/10.17073/0021-3438-2018-4-53-59","url":null,"abstract":"It is known that casting long ingots of small sections (∅8–12 mm) of 01417 alloy into an electromagnetic crystallizer makes it possible to obtain a dispersed structure with insignificant intradendritic segregation. Diffusion annealing of ingots (550 °C, 4–5 h holding time) eliminates intracrystalline segregation and reduces the level of internal stresses in metal thus providing the conditions for subsequent wire drawing. The paper demonstrates that high plastic deformation of ingots without diffusion annealing can be achieved by Conform continuous extrusion, which ensures high quality and geometrical accuracy of products. The analysis of various Conform units revealed an inherent weakness – the absence of connection between the system securing the fixed part of the detachable container (shoe) and the drive wheel shaft, which leads to an increased load in the operating mode. The purpose of the work was to upgrade the Conform unit by creating a connection between the shoe and the impeller shaft to obtain a high-quality billet for subsequent wire drawing of the ∅12 mm ingot cast into the electromagnetic crystallizer. An optimal temperature of ingot extrusion (300 °С) was found to eliminate the intense adhesion of wrought metal on the tool surface. The experimental ∅5 mm rod made of 01417 alloy obtained from the ∅12 mm ingot at the Conform unit features high processing ductility. This is indicated by an increase in its yield point and relative elongation. Metallographic studies demonstrated a fine-grained structure achieved in the extruded rod, which provides the conditions for subsequent wire drawing without annealing. The results of the study provide a basis for refining the process conditions of calibrated billet production on the Conform unit followed by wire drawing with required properties.","PeriodicalId":14523,"journal":{"name":"Izvestiya Vuzov Tsvetnaya Metallurgiya (Proceedings of Higher Schools Nonferrous Metallurgy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90578292","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 : 2018-08-16DOI: 10.17073/0021-3438-2018-4-45-52
K. Nikitin, I. Timoshkin, V. I. Nikitin
A comparative study on the effect of methods for obtaining AlTi4 modifying master alloys on the sizes of Al3Ti intermetallics is made. It is found that increasing cooling rates at solidification from 10–15 °C/s (crystallization in a hot cast iron mold, a plate 30 mm in thickness) to 60–65 °C/s (crystallization in a cold cast iron chill mold, a rod 20 mm in diameter, 170 mm in length) reduces the length and thickness of needle-shaped intermetallics almost twice (397×23 to 215×13 μm). At the same time, lower electrical conductivity and higher alloy density in a solid state are observed. Melt modification with 0,5 wt.% magnesium addition causes the formation of homogeneous 98×3 μm fine-needle intermetallics. The addition of magnesium slightly reduces electrical conductivity and density compared with the AlTi4 master alloy crystallized at the same cooling rate (60–65 °C/s). Modification of A97 grade aluminum and AK9ch alloy (Al–Si–Mg system) with the specified master alloys at the same amount of titanium added (0,01 wt.%) exerts hereditary influence on the density and electrical conductivity, and macrograin (A97) and dendrites of aluminium (AK9ch). The maximum modifying effect is provided by the AlTi4 master alloy containing 0,5 wt.% magnesium. When introduced into the alloy, it contributes to the formation of 10 μm aluminum dendrites 1427 pcs/mm2 in total in the alloy structure. When the AK9ch alloy is modified with the master alloy crystallized at cooling rates of 10–15 °C/s, 28 μm dendrites 672 pcs/mm2 in total are formed in the alloy structure. It is suggested to use density and electrical conductivity determination methods for express evaluation of master alloy modifying effectiveness.
{"title":"INFLUENCE OF METHODS FOR ALTI MASTER ALLOY PRODUCTION ON ITS STRUCTURE AND EFFICIENCY IN ALUMINUM ALLOY MODIFICATION","authors":"K. Nikitin, I. Timoshkin, V. I. Nikitin","doi":"10.17073/0021-3438-2018-4-45-52","DOIUrl":"https://doi.org/10.17073/0021-3438-2018-4-45-52","url":null,"abstract":"A comparative study on the effect of methods for obtaining AlTi4 modifying master alloys on the sizes of Al3Ti intermetallics is made. It is found that increasing cooling rates at solidification from 10–15 °C/s (crystallization in a hot cast iron mold, a plate 30 mm in thickness) to 60–65 °C/s (crystallization in a cold cast iron chill mold, a rod 20 mm in diameter, 170 mm in length) reduces the length and thickness of needle-shaped intermetallics almost twice (397×23 to 215×13 μm). At the same time, lower electrical conductivity and higher alloy density in a solid state are observed. Melt modification with 0,5 wt.% magnesium addition causes the formation of homogeneous 98×3 μm fine-needle intermetallics. The addition of magnesium slightly reduces electrical conductivity and density compared with the AlTi4 master alloy crystallized at the same cooling rate (60–65 °C/s). Modification of A97 grade aluminum and AK9ch alloy (Al–Si–Mg system) with the specified master alloys at the same amount of titanium added (0,01 wt.%) exerts hereditary influence on the density and electrical conductivity, and macrograin (A97) and dendrites of aluminium (AK9ch). The maximum modifying effect is provided by the AlTi4 master alloy containing 0,5 wt.% magnesium. When introduced into the alloy, it contributes to the formation of 10 μm aluminum dendrites 1427 pcs/mm2 in total in the alloy structure. When the AK9ch alloy is modified with the master alloy crystallized at cooling rates of 10–15 °C/s, 28 μm dendrites 672 pcs/mm2 in total are formed in the alloy structure. It is suggested to use density and electrical conductivity determination methods for express evaluation of master alloy modifying effectiveness.","PeriodicalId":14523,"journal":{"name":"Izvestiya Vuzov Tsvetnaya Metallurgiya (Proceedings of Higher Schools Nonferrous Metallurgy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84274778","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 : 2018-08-16DOI: 10.17073/0021-3438-2018-4-15-23
V. Yegorov, O. Makovskaya, S. Mamyachenkov, P. Kozlov
The article considers possibility of using inorganic sorbent – iron oxyhydrate (IOH) – to remove F– ions from process solutions of zinc production. The method of IOH synthesis is chosen. The results of scanning electron microscopy and X-ray phase analysis are presented. The principal possibility of using ion-exchange resins as IOH-modified carriers is considered. The paper studies active substance formation on anion and cation exchange resins. It is shown that the most durable composite sorbents are obtained using strongly acidic cation exchange resins with SO3– groups. A method for introducing IOH into the structure of carrier materials and obtaining composite sorbents is described. The KU-2×8 strongly acidic cation exchanger is recommended as a composite base. Cation exchangers saturated with iron were held in a sodium chloride solution with a concentration of 2,5 g/dm3 for 24 hours at 85 °C to ensure formation of β-modification IOH crystals distributed over the ion exchanger grain volume. Anion exchangers were held in an iron(III) sulfate solution with added sodium chloride for 24 hours at 85 °C. At the same time, iron oxyhydrate films formed on the surface of sorbent grains were observed. Fluorine sorption was carried out in a static mode from a standardized test solution with a concentration of F– = 100 mg/dm3 at 60 °C. Sorption on the AB-17×8 anionite was carried out at 20 °C. Absorbed fluorine was desorbed by the NaOH (0,1 M) solution at 60 °C for 2 hours. The synthesized KU-2×8-IOH composite sorbent has a fluorine capacity of 0,7–1,1 mg/g, and can be regenerated with resulting easily utilizable fluorine-containing eluate.
{"title":"SORPTION OF FLUORIDE IONS BY IRON OXYHYDRATE FIXED ON THE CARRIERS. Part 1. Organic carriers","authors":"V. Yegorov, O. Makovskaya, S. Mamyachenkov, P. Kozlov","doi":"10.17073/0021-3438-2018-4-15-23","DOIUrl":"https://doi.org/10.17073/0021-3438-2018-4-15-23","url":null,"abstract":"The article considers possibility of using inorganic sorbent – iron oxyhydrate (IOH) – to remove F– ions from process solutions of zinc production. The method of IOH synthesis is chosen. The results of scanning electron microscopy and X-ray phase analysis are presented. The principal possibility of using ion-exchange resins as IOH-modified carriers is considered. The paper studies active substance formation on anion and cation exchange resins. It is shown that the most durable composite sorbents are obtained using strongly acidic cation exchange resins with SO3– groups. A method for introducing IOH into the structure of carrier materials and obtaining composite sorbents is described. The KU-2×8 strongly acidic cation exchanger is recommended as a composite base. Cation exchangers saturated with iron were held in a sodium chloride solution with a concentration of 2,5 g/dm3 for 24 hours at 85 °C to ensure formation of β-modification IOH crystals distributed over the ion exchanger grain volume. Anion exchangers were held in an iron(III) sulfate solution with added sodium chloride for 24 hours at 85 °C. At the same time, iron oxyhydrate films formed on the surface of sorbent grains were observed. Fluorine sorption was carried out in a static mode from a standardized test solution with a concentration of F– = 100 mg/dm3 at 60 °C. Sorption on the AB-17×8 anionite was carried out at 20 °C. Absorbed fluorine was desorbed by the NaOH (0,1 M) solution at 60 °C for 2 hours. The synthesized KU-2×8-IOH composite sorbent has a fluorine capacity of 0,7–1,1 mg/g, and can be regenerated with resulting easily utilizable fluorine-containing eluate.","PeriodicalId":14523,"journal":{"name":"Izvestiya Vuzov Tsvetnaya Metallurgiya (Proceedings of Higher Schools Nonferrous Metallurgy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90901155","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 : 2018-08-16DOI: 10.17073/0021-3438-2018-4-31-44
A. Gasanov, A. Naumov, O. V. Yurasova, I. Petrov, T. Litvinova
The paper presents a review of some trends observed on the world market of rare-earth elements (REE). This review takes into account actual changes in the commercial and industrial policy of China and the current trends of REE consumption. Main characteristics of the modern REE markets are considered. The paper provides an assessment of world production volumes, world trade and prices. The article describes the REE market behavior in 2000–2020 and provides a forecast of main indicators and prices up to 2020. It contains a description of current world REE resources, production and trade over the main countries. In addition, the prices and the main buyers of REE are specified indicating the forecast of consumption. The prospects of the Russian REE market are estimated taking into account the «Development of the Rare and Rare-Earth Elements Industry» subprogram implemented as part of the State Program of the Russian Federation «Industry Development and Competitiveness Improvement». The purpose of the subprogram is to create a competitive rare-earth industry of an integrated production cycle in the Russian Federation in order to satisfy the needs of the domestic defense industry complex, civil industries and enter the foreign markets. It is noted that this subprogram should be upgraded with regard to changes in the market conditions and development of rare-earth elements production in the Russian Federation including by means of statutory, non-tariff and technical regulation. Loparite and apatite will remain the main sources of rare-earth elements as raw materials for industrial processing in Russia in the near future, while REE production from apatite will increase. It is emphasized that the prospects of REE development in Russia consist not so much in increasing the primary production as in establishing new plants consuming rare-earth products.
{"title":"SOME TRENDS OF THE WORLD REE MARKET AND PROSPECTS FOR RUSSIA","authors":"A. Gasanov, A. Naumov, O. V. Yurasova, I. Petrov, T. Litvinova","doi":"10.17073/0021-3438-2018-4-31-44","DOIUrl":"https://doi.org/10.17073/0021-3438-2018-4-31-44","url":null,"abstract":"The paper presents a review of some trends observed on the world market of rare-earth elements (REE). This review takes into account actual changes in the commercial and industrial policy of China and the current trends of REE consumption. Main characteristics of the modern REE markets are considered. The paper provides an assessment of world production volumes, world trade and prices. The article describes the REE market behavior in 2000–2020 and provides a forecast of main indicators and prices up to 2020. It contains a description of current world REE resources, production and trade over the main countries. In addition, the prices and the main buyers of REE are specified indicating the forecast of consumption. The prospects of the Russian REE market are estimated taking into account the «Development of the Rare and Rare-Earth Elements Industry» subprogram implemented as part of the State Program of the Russian Federation «Industry Development and Competitiveness Improvement». The purpose of the subprogram is to create a competitive rare-earth industry of an integrated production cycle in the Russian Federation in order to satisfy the needs of the domestic defense industry complex, civil industries and enter the foreign markets. It is noted that this subprogram should be upgraded with regard to changes in the market conditions and development of rare-earth elements production in the Russian Federation including by means of statutory, non-tariff and technical regulation. Loparite and apatite will remain the main sources of rare-earth elements as raw materials for industrial processing in Russia in the near future, while REE production from apatite will increase. It is emphasized that the prospects of REE development in Russia consist not so much in increasing the primary production as in establishing new plants consuming rare-earth products.","PeriodicalId":14523,"journal":{"name":"Izvestiya Vuzov Tsvetnaya Metallurgiya (Proceedings of Higher Schools Nonferrous Metallurgy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91280352","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 : 2018-06-14DOI: 10.17073/0021-3438-2018-3-59-67
K. Y. Chervyakova, N. Belov, M. Samoshina, A. Yakovlev
Al–Cu–Mn (Zr) alloys feature high strength and processability without any thermal treatment operations. Al–2%Cu–1,5%Mn–2%B and Al–2%Cu–1,5%Mn–0,4%Zr–2%B alloys were obtained in order to investigate the possibility of producing a aluminum boroncontaining alloy in the form of high-strength sheet rolled stock without thermal treatment. Melting was performed in the RELTEK induction furnace with intense melt stirring to eliminate sedimentation of boride refractory particles. Melting temperature was 950– 1000 °С. Melt was poured into 40×120×200 mm graphite casting molds. Calculation methods (Thermo-Calc) were used to demonstrate that manganese forms complex borides with aluminum and zirconium at a melting temperature while there is enough manganese in liquid and there is practically no zirconium left. Experimental methods (electronic scanning microscopy and electron microprobe analysis) proved the formation of the complex AlB2Mn2 boride, however, manganese remained in a solid solution is enough to form the Al20Cu2Mn3 phase particles in the amount up to 7 wt.%. In the alloy with zirconium, boron stimulates primary Al3Zr crystal separation and, therefore, zirconium content left in the aluminum solid solution is not sufficient for hardening. It is shown that it is possible to produce thin-rolled steel with a thickness of less than 0,3 mm with uniformly distributed clusters of the boride phase with a particle size of less than 10 μm. A high level of strength up to 543 MPa is reached without the use of hardening and aging due to the precipitation of Al20Cu2Mn3 phase dispersions during hot deformation (t =450 °C).
{"title":"INVESTIGATION OF POSSIBILITY TO PRODUCE HIGH-STRENGTH BORON ALUMINUM SHEETS WITHOUT HOMOGENIZATION AND QUENCHING OPERATIONS","authors":"K. Y. Chervyakova, N. Belov, M. Samoshina, A. Yakovlev","doi":"10.17073/0021-3438-2018-3-59-67","DOIUrl":"https://doi.org/10.17073/0021-3438-2018-3-59-67","url":null,"abstract":"Al–Cu–Mn (Zr) alloys feature high strength and processability without any thermal treatment operations. Al–2%Cu–1,5%Mn–2%B and Al–2%Cu–1,5%Mn–0,4%Zr–2%B alloys were obtained in order to investigate the possibility of producing a aluminum boroncontaining alloy in the form of high-strength sheet rolled stock without thermal treatment. Melting was performed in the RELTEK induction furnace with intense melt stirring to eliminate sedimentation of boride refractory particles. Melting temperature was 950– 1000 °С. Melt was poured into 40×120×200 mm graphite casting molds. Calculation methods (Thermo-Calc) were used to demonstrate that manganese forms complex borides with aluminum and zirconium at a melting temperature while there is enough manganese in liquid and there is practically no zirconium left. Experimental methods (electronic scanning microscopy and electron microprobe analysis) proved the formation of the complex AlB2Mn2 boride, however, manganese remained in a solid solution is enough to form the Al20Cu2Mn3 phase particles in the amount up to 7 wt.%. In the alloy with zirconium, boron stimulates primary Al3Zr crystal separation and, therefore, zirconium content left in the aluminum solid solution is not sufficient for hardening. It is shown that it is possible to produce thin-rolled steel with a thickness of less than 0,3 mm with uniformly distributed clusters of the boride phase with a particle size of less than 10 μm. A high level of strength up to 543 MPa is reached without the use of hardening and aging due to the precipitation of Al20Cu2Mn3 phase dispersions during hot deformation (t =450 °C).","PeriodicalId":14523,"journal":{"name":"Izvestiya Vuzov Tsvetnaya Metallurgiya (Proceedings of Higher Schools Nonferrous Metallurgy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90062292","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 : 2018-06-14DOI: 10.17073/0021-3438-2018-3-84-94
A. Timofeev, A. Logacheva
OJSC «Kompozit» traces its history back to the Central Research Institute of Materials Science (CRIMS) and successfully acts as a leading material science institute in the rocket and space industry up to the present day. The enterprise uses and improves state-of-theart technologies, and creates a variety of new metal, non-metallic, composite and ceramic materials. This article provides an overview of powder sector development from the metallurgy of granules to additive technologies and shows the participation of MISIS graduates. The experience of OJSC «Kompozit» in the manufacturing of parts by selective electron beam melting (SEBM) of home-made VT6S titanium alloy powders. Initial powders are obtained by plasma centrifugal spraying of the bar stock. It is shown that the powders feature an ideal spherical shape, low defect rate, high processability and fully meet the process requirements. The microstructure and properties of samples and parts obtained by the SEBM are studied.
{"title":"FROM METALLURGY OF GRANULES TO ADDITIVE TECHNOLOGIES","authors":"A. Timofeev, A. Logacheva","doi":"10.17073/0021-3438-2018-3-84-94","DOIUrl":"https://doi.org/10.17073/0021-3438-2018-3-84-94","url":null,"abstract":"OJSC «Kompozit» traces its history back to the Central Research Institute of Materials Science (CRIMS) and successfully acts as a leading material science institute in the rocket and space industry up to the present day. The enterprise uses and improves state-of-theart technologies, and creates a variety of new metal, non-metallic, composite and ceramic materials. This article provides an overview of powder sector development from the metallurgy of granules to additive technologies and shows the participation of MISIS graduates. The experience of OJSC «Kompozit» in the manufacturing of parts by selective electron beam melting (SEBM) of home-made VT6S titanium alloy powders. Initial powders are obtained by plasma centrifugal spraying of the bar stock. It is shown that the powders feature an ideal spherical shape, low defect rate, high processability and fully meet the process requirements. The microstructure and properties of samples and parts obtained by the SEBM are studied.","PeriodicalId":14523,"journal":{"name":"Izvestiya Vuzov Tsvetnaya Metallurgiya (Proceedings of Higher Schools Nonferrous Metallurgy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82850375","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 : 2018-06-14DOI: 10.17073/0021-3438-2018-3-68-83
A. Krokhalev, V. Kharlamov, S. Kuzmin, V. Lysak
The article presents experimental data on explosive compaction of chromium carbide (Cr3C2) powder mixtures with metals (Ti, Ni, Cu) provided with theoretical explanations. These data were used as a basis for stating science-based principles of composition selection and technology development to produce antifriction wear-resistant chromium carbide hard alloys and coatings by explosion. Explosive compaction of powder mixtures was carried out according to a scheme using a normally incident plane detonation wave in a wide range of loading parameters (powder heating temperature in shock waves varied from 200 to1000 °Cand maximum shock compression pressure varied from 4 to 16 GPa during experiments). Phase transformation analysis was carried out by the numerical thermodynamic modeling of phase equilibrium using the Thermo-Calc software. Microstructure, chemical and phase compositions were studied using optical («Axiovert 40МАТ» by CarlZeiss,Germany), scanning («Versa 3D» and «Quanta 3D FEG» byFEI,USA), transmission («BS 540» byTesla,Czech Republic, «Titan 80-300» and «Tecnai G2 20F» byFEI,USA) electron microscopes and «Solver Pro» atomic force microscope (LLC «NT-MDT», Zelenograd). Temperature stability and oxidation resistance at elevated temperatures of the materials obtained by explosion was studied using thermogravimetric analysis (TGA) using the «STA 449 F3 Jupiter» instrument (NETZSCH, Germany) in the synthetic air environment when heated to1500 °C. Tribological tests were carried out on the MI-1M friction machine (MEZIMiV,Moscow) according to the pin-on-ring scheme with plunging in distilled water environment. The mechanisms of consolidation and formation of strong boundaries between powder material particles during explosive compaction are described. It is shown that hard alloys of chromium carbide with titanium bond obtained by explosion retain their phase compositions without any changes and resist to oxidation up to600 °C, and also have significantly better anti-friction properties and wear resistance than the SGP-0,5 and KHN-20 materials used in water-lubricated friction couples until the present time.
{"title":"FUNDAMENTALS OF WEAR-RESISTANT COATING PRODUCTION FROM CHROMIUM CARBIDE POWDER MIXTURE WITH BINDER METAL BY EXPLOSIVE COMPACTION","authors":"A. Krokhalev, V. Kharlamov, S. Kuzmin, V. Lysak","doi":"10.17073/0021-3438-2018-3-68-83","DOIUrl":"https://doi.org/10.17073/0021-3438-2018-3-68-83","url":null,"abstract":"The article presents experimental data on explosive compaction of chromium carbide (Cr3C2) powder mixtures with metals (Ti, Ni, Cu) provided with theoretical explanations. These data were used as a basis for stating science-based principles of composition selection and technology development to produce antifriction wear-resistant chromium carbide hard alloys and coatings by explosion. Explosive compaction of powder mixtures was carried out according to a scheme using a normally incident plane detonation wave in a wide range of loading parameters (powder heating temperature in shock waves varied from 200 to1000 °Cand maximum shock compression pressure varied from 4 to 16 GPa during experiments). Phase transformation analysis was carried out by the numerical thermodynamic modeling of phase equilibrium using the Thermo-Calc software. Microstructure, chemical and phase compositions were studied using optical («Axiovert 40МАТ» by CarlZeiss,Germany), scanning («Versa 3D» and «Quanta 3D FEG» byFEI,USA), transmission («BS 540» byTesla,Czech Republic, «Titan 80-300» and «Tecnai G2 20F» byFEI,USA) electron microscopes and «Solver Pro» atomic force microscope (LLC «NT-MDT», Zelenograd). Temperature stability and oxidation resistance at elevated temperatures of the materials obtained by explosion was studied using thermogravimetric analysis (TGA) using the «STA 449 F3 Jupiter» instrument (NETZSCH, Germany) in the synthetic air environment when heated to1500 °C. Tribological tests were carried out on the MI-1M friction machine (MEZIMiV,Moscow) according to the pin-on-ring scheme with plunging in distilled water environment. The mechanisms of consolidation and formation of strong boundaries between powder material particles during explosive compaction are described. It is shown that hard alloys of chromium carbide with titanium bond obtained by explosion retain their phase compositions without any changes and resist to oxidation up to600 °C, and also have significantly better anti-friction properties and wear resistance than the SGP-0,5 and KHN-20 materials used in water-lubricated friction couples until the present time.","PeriodicalId":14523,"journal":{"name":"Izvestiya Vuzov Tsvetnaya Metallurgiya (Proceedings of Higher Schools Nonferrous Metallurgy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79909738","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 : 2018-06-14DOI: 10.17073/0021-3438-2018-3-49-58
A. Zaitsev, I. Konyashin, E. N. Avdeenko, N. Shvyndina, E. Levashov
The structure and magnetic properties of model high-cobalt WC–50%Co alloys with different carbon content and 1,6–5,6 wt.% TaC additives are studied. Model alloys are obtained by liquid-phase sintering of powder mixtures at 1420 °C, and their composition is described by the formula: 50%Co + 50%WC + xTaC + yC, where x = 0; 1,6; 2,6; 3,6; 4,6; 5,6 wt.%, y = 0; 0,2; 0,5 wt.%. It is shown that (Ta,W)C phase precipitates are present in all the investigated alloys, whereby at up to 3,6 wt.% TaC concentration the (Ta,W)C grains have a needle shape, and at ³3,6 wt.% TaC concentration the shape of the (Ta,W)C grains becomes spherical. (Ta,W)C phase precipitates are located both in the Co-binder and along the WC grain boundaries. The (Ta,W)C phase lattice parameter in low-carbon alloys lies in the range from 0,4438 nm for the 1,6 % TaC alloy up to 0,4451 nm for the 4,6 % TaC alloy. According to EDX analysis, the concentration of dissolved tungsten in the cobalt phase is independent of the TaC content and strongly depends on the total carbon content, and for alloys with high, elevated and low carbon content it is 7, 12 and 17 wt.%, respectively. TaC addition in alloys with a low and elevated carbon content leads to an increase in coercive force by 875 A/m and a decrease in magnetic saturation by 5–10 Gs·m3/g. The experimental results allowed putting forward a hypothesis about the possibility of forming dispersed tantalumcontaining precipitates in the binder phase.
{"title":"STRUCTURE AND MAGNETIC PROPERTIES OF WC–50%Cо MODEL ALLOYS CONTAINING TaC ADDITIVES","authors":"A. Zaitsev, I. Konyashin, E. N. Avdeenko, N. Shvyndina, E. Levashov","doi":"10.17073/0021-3438-2018-3-49-58","DOIUrl":"https://doi.org/10.17073/0021-3438-2018-3-49-58","url":null,"abstract":"The structure and magnetic properties of model high-cobalt WC–50%Co alloys with different carbon content and 1,6–5,6 wt.% TaC additives are studied. Model alloys are obtained by liquid-phase sintering of powder mixtures at 1420 °C, and their composition is described by the formula: 50%Co + 50%WC + xTaC + yC, where x = 0; 1,6; 2,6; 3,6; 4,6; 5,6 wt.%, y = 0; 0,2; 0,5 wt.%. It is shown that (Ta,W)C phase precipitates are present in all the investigated alloys, whereby at up to 3,6 wt.% TaC concentration the (Ta,W)C grains have a needle shape, and at ³3,6 wt.% TaC concentration the shape of the (Ta,W)C grains becomes spherical. (Ta,W)C phase precipitates are located both in the Co-binder and along the WC grain boundaries. The (Ta,W)C phase lattice parameter in low-carbon alloys lies in the range from 0,4438 nm for the 1,6 % TaC alloy up to 0,4451 nm for the 4,6 % TaC alloy. According to EDX analysis, the concentration of dissolved tungsten in the cobalt phase is independent of the TaC content and strongly depends on the total carbon content, and for alloys with high, elevated and low carbon content it is 7, 12 and 17 wt.%, respectively. TaC addition in alloys with a low and elevated carbon content leads to an increase in coercive force by 875 A/m and a decrease in magnetic saturation by 5–10 Gs·m3/g. The experimental results allowed putting forward a hypothesis about the possibility of forming dispersed tantalumcontaining precipitates in the binder phase.","PeriodicalId":14523,"journal":{"name":"Izvestiya Vuzov Tsvetnaya Metallurgiya (Proceedings of Higher Schools Nonferrous Metallurgy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78961867","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 : 2018-06-14DOI: 10.17073/0021-3438-2018-3-19-35
Y. Karpov, V. B. Baranovskaya
The article focuses on one of the important issues in rare and precious metals industry development – analytical control. It reviews the current state, importance, problems and prospects for analytical control development as an integral part of the rare and precious metal production and product quality assurance. Modern analytical control methods are described, namely atomic spectral, mass spectral, X-ray fluorescent and combined ones as well as their rational applications. It is shown that scientific and technological progress is inextricably linked with a drastic increase in the nomenclature of materials based on rare and precious metals and higher requirements for their quality. This will require creating new and improving existing analytical control methods, their standardization and metrological support. This work should involve research organizations in theRussianAcademy of Sciences, universities, industry research centers with research laboratories that have survived in the country after theSoviet Union dissolution, as well as promote plant research activities. It is necessary to effectively use the achievements of advanced analytical laboratories abroad, participate in international comparative tests. At the same time, special attention is paid to unsolved problems – scientifically justified statement of requirements for new types of products based on rare and precious metals; development and metrological assessment of sampling methods; development of high-quality metrological support for analytical control of rare and precious metal production; improvement of analytical methods; standardization of analytical methods; accreditation of analytical laboratories; training of highly qualified analytical chemists.
{"title":"PROBLEMS OF ANALYTICAL CONTROL IN PRODUCTION OF RARE AND PRECIOUS METALS","authors":"Y. Karpov, V. B. Baranovskaya","doi":"10.17073/0021-3438-2018-3-19-35","DOIUrl":"https://doi.org/10.17073/0021-3438-2018-3-19-35","url":null,"abstract":"The article focuses on one of the important issues in rare and precious metals industry development – analytical control. It reviews the current state, importance, problems and prospects for analytical control development as an integral part of the rare and precious metal production and product quality assurance. Modern analytical control methods are described, namely atomic spectral, mass spectral, X-ray fluorescent and combined ones as well as their rational applications. It is shown that scientific and technological progress is inextricably linked with a drastic increase in the nomenclature of materials based on rare and precious metals and higher requirements for their quality. This will require creating new and improving existing analytical control methods, their standardization and metrological support. This work should involve research organizations in theRussianAcademy of Sciences, universities, industry research centers with research laboratories that have survived in the country after theSoviet Union dissolution, as well as promote plant research activities. It is necessary to effectively use the achievements of advanced analytical laboratories abroad, participate in international comparative tests. At the same time, special attention is paid to unsolved problems – scientifically justified statement of requirements for new types of products based on rare and precious metals; development and metrological assessment of sampling methods; development of high-quality metrological support for analytical control of rare and precious metal production; improvement of analytical methods; standardization of analytical methods; accreditation of analytical laboratories; training of highly qualified analytical chemists.","PeriodicalId":14523,"journal":{"name":"Izvestiya Vuzov Tsvetnaya Metallurgiya (Proceedings of Higher Schools Nonferrous Metallurgy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83981847","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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