Pub Date : 2019-06-19DOI: 10.17073/0021-3438-2019-3-47-55
E. Nosova, A. Fadeeva, M. Starodubtseva
The quality of products made of sheet aluminum alloys strongly depends on the technological features of the sheet stamping process, as well as on the structure of sheet semi-finished products. The grain size and grain structure uniformity are among the key structural features that influence stampability. A method is proposed and the homogeneity of the grain structure is evaluated. Stampability of Al2Mg and Al6Mg aluminium alloys was evaluated based on measurements of the spring back index, minimum bending radius, stamping ratio, and Martens strain index. Cold work (with a strain degree of 20 %) and subsequent recrystallization annealing at temperatures of 250, 350 and 450 °C for 1 h were used to obtain a grain structure of (26,8 Ѓ} 7,4)÷(126 Ѓ} 43) μm (Al6Mg alloy) and (120 Ѓ} 11)÷(264 Ѓ} 130) μm (Al2Mg alloy) in size. As a result of processing, the effect of the initial grain size was revealed: the coarser structure of the Al2Mg alloy led to a larger grain size after strain and annealing. It was found that an increase in the grain size in both alloys leads to an increase in the Martens index and a decrease in the stamping ratio, which indicates higher stampability of the alloys in the drawing operations of sheet stamping. In the Al2Mg alloy, an increase in the grain size leads to a decrease in the spring back index by 1,5–1,7 times, and an increase in the minimum bending radius. In the Al6Mg alloy, an increase in the grain size leads to an increase in the spring back index by 1,1–1,2 times, and a decrease in the minimum bending radius. The Al6Mg minimum bending radius remains higher compared to Al2Mg regardless of the grain size. Grain size inhomogeneity in the Al6Mg alloy causes an increase in the Martens index and minimum bending radius, and a decrease in the stamping ratio. In the Al2Mg alloy, grain size inhomogeneity causes an increase in the Martens index and minimum bending radius, and a decrease in the stamping ratio. For the spring back index, the increase in grain size inhomogeneity causes a high scatter of data. In the Al6Mg alloy, the low annealing temperature led to the preservation of the non-recrystallized structure, which influenced the decrease in stampability.
{"title":"Research of grain size homogeneity effect on sheet stamping ability characteristics of Al2Mg and Al6Mg alloys","authors":"E. Nosova, A. Fadeeva, M. Starodubtseva","doi":"10.17073/0021-3438-2019-3-47-55","DOIUrl":"https://doi.org/10.17073/0021-3438-2019-3-47-55","url":null,"abstract":"The quality of products made of sheet aluminum alloys strongly depends on the technological features of the sheet stamping process, as well as on the structure of sheet semi-finished products. The grain size and grain structure uniformity are among the key structural features that influence stampability. A method is proposed and the homogeneity of the grain structure is evaluated. Stampability of Al2Mg and Al6Mg aluminium alloys was evaluated based on measurements of the spring back index, minimum bending radius, stamping ratio, and Martens strain index. Cold work (with a strain degree of 20 %) and subsequent recrystallization annealing at temperatures of 250, 350 and 450 °C for 1 h were used to obtain a grain structure of (26,8 Ѓ} 7,4)÷(126 Ѓ} 43) μm (Al6Mg alloy) and (120 Ѓ} 11)÷(264 Ѓ} 130) μm (Al2Mg alloy) in size. As a result of processing, the effect of the initial grain size was revealed: the coarser structure of the Al2Mg alloy led to a larger grain size after strain and annealing. It was found that an increase in the grain size in both alloys leads to an increase in the Martens index and a decrease in the stamping ratio, which indicates higher stampability of the alloys in the drawing operations of sheet stamping. In the Al2Mg alloy, an increase in the grain size leads to a decrease in the spring back index by 1,5–1,7 times, and an increase in the minimum bending radius. In the Al6Mg alloy, an increase in the grain size leads to an increase in the spring back index by 1,1–1,2 times, and a decrease in the minimum bending radius. The Al6Mg minimum bending radius remains higher compared to Al2Mg regardless of the grain size. Grain size inhomogeneity in the Al6Mg alloy causes an increase in the Martens index and minimum bending radius, and a decrease in the stamping ratio. In the Al2Mg alloy, grain size inhomogeneity causes an increase in the Martens index and minimum bending radius, and a decrease in the stamping ratio. For the spring back index, the increase in grain size inhomogeneity causes a high scatter of data. In the Al6Mg alloy, the low annealing temperature led to the preservation of the non-recrystallized structure, which influenced the decrease in stampability.","PeriodicalId":14523,"journal":{"name":"Izvestiya Vuzov Tsvetnaya Metallurgiya (Proceedings of Higher Schools Nonferrous Metallurgy","volume":"7 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78701790","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 : 2019-06-19DOI: 10.17073/0021-3438-2019-3-12-19
G. E. Nagibin, A. Zavadyak, I. I. Puzanov, A. Proshkin, E. Fedorova, S. S. Dobrosmyslov, I. Kirillova, N. V. Sukhodoeva
The paper presents the developed composition and technology for obtaining a repair mixture consisting of lumped corundum with a TiB2–C composite coating wettable with aluminum for restoration of local bottom block fractures without electrolyzer stops. The proposed technical solution made it possible to reduce bottom wear and increase aluminum electrolyzer service life by 6 months.A mixture of titanium diboride powder and a refractory powder-like binder in a ratio of 50 : 50 (wt.%) was used to obtain the repair mixture with an optimal composition. Then the lumped corundum was coated with the obtained mixture, dried at 150 °C and after that heat-treated under a carbon-bed at t= 700÷900 °C. As a result of reducing firing the TiB2–C composite material with a carbon content of 15–20 wt.% was formed on the surface of lumped corundum. A qualitative evaluation of the properties of the developed composite coating shows that the coating has a sufficiently high hardness, wear resistance and adhesion to the substrate after the heat treatment. For pilot testing, the repair mixture was covered with molten aluminum to obtain an Al–TiB2–C repair mass in the form of plates. The pilot testing of the repair mass on the 400 kA operating electrolyzer in the RUSAL-Sayanogorsk pilot shop showed that the bottom wear have slowed down 3 months after the local fractures were restored without electrolysis bath stops. This fact is evidenced by a 13 % decrease in the average depth of fractures with a stable current value of 4,7–4,8 kA/bloom after repair. Thus, the locallyused repair mass slowed that the overall wear of the cathode surface and allowed to extend the electrolyzer life.
{"title":"Development and industrial tests of composite material based on TiB2 for repair of local destructions in electrolyzer bottom blocks","authors":"G. E. Nagibin, A. Zavadyak, I. I. Puzanov, A. Proshkin, E. Fedorova, S. S. Dobrosmyslov, I. Kirillova, N. V. Sukhodoeva","doi":"10.17073/0021-3438-2019-3-12-19","DOIUrl":"https://doi.org/10.17073/0021-3438-2019-3-12-19","url":null,"abstract":"The paper presents the developed composition and technology for obtaining a repair mixture consisting of lumped corundum with a TiB2–C composite coating wettable with aluminum for restoration of local bottom block fractures without electrolyzer stops. The proposed technical solution made it possible to reduce bottom wear and increase aluminum electrolyzer service life by 6 months.A mixture of titanium diboride powder and a refractory powder-like binder in a ratio of 50 : 50 (wt.%) was used to obtain the repair mixture with an optimal composition. Then the lumped corundum was coated with the obtained mixture, dried at 150 °C and after that heat-treated under a carbon-bed at t= 700÷900 °C. As a result of reducing firing the TiB2–C composite material with a carbon content of 15–20 wt.% was formed on the surface of lumped corundum. A qualitative evaluation of the properties of the developed composite coating shows that the coating has a sufficiently high hardness, wear resistance and adhesion to the substrate after the heat treatment. For pilot testing, the repair mixture was covered with molten aluminum to obtain an Al–TiB2–C repair mass in the form of plates. The pilot testing of the repair mass on the 400 kA operating electrolyzer in the RUSAL-Sayanogorsk pilot shop showed that the bottom wear have slowed down 3 months after the local fractures were restored without electrolysis bath stops. This fact is evidenced by a 13 % decrease in the average depth of fractures with a stable current value of 4,7–4,8 kA/bloom after repair. Thus, the locallyused repair mass slowed that the overall wear of the cathode surface and allowed to extend the electrolyzer life.","PeriodicalId":14523,"journal":{"name":"Izvestiya Vuzov Tsvetnaya Metallurgiya (Proceedings of Higher Schools Nonferrous Metallurgy","volume":"27 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80967458","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 : 2019-06-19DOI: 10.17073/0021-3438-2019-3-68-76
A. Rakoch, N. A. Predein, A. A. Gladkova, A. Koltygin, V. V. Vorozhtsova
Alloy composition was developed and heat treatment conditions were selected to obtain an intensively dissolving magnesium alloy to be used as a ball plug under oil-well precommissioning conditions, i.e. to seal various well sections with further near-complete destruction of these plugs for a short time (up to 11 h). It was found that the reason of high dissolution rate of Mg alloy with a composition similar to high-strength ML6 is a higher nickel content (up to 0,19 %). The compounds of this element are located along the grain boundaries, and it leads to intense intercrystalline corrosion of the alloy in a medium containing chlorine ions. It is shown that an effective method for controlling the Mg alloy dissolution rate is to synthesize coatings on its surface with various thicknesses by plasma electrolytic treatment (PET) in aqueous solution containing 110 g/l of commercial water glass. This method allowed synthesizing coatings with a thickness from 10 to 41 μm on the experimental magnesium alloy with increased nickel concentrations (~ 0,19 %) in a short period of time (from 10 to 20 min) with low set AC current density (4 A/dm2) – galvanostatic mode of PET processes. Corrosion investigations were carried out in 3 % KCl aqueous solution at 93 ± 2 °C. PET coatings were obtained on the magnesium alloy using a capacitive unit. Corrosion tests conditions for materials used as ball plugs in oil well seals were similar to that cited in foreign researches.
{"title":"Development of high-magnesium alloy composition to create a temporary seals used in oil industry","authors":"A. Rakoch, N. A. Predein, A. A. Gladkova, A. Koltygin, V. V. Vorozhtsova","doi":"10.17073/0021-3438-2019-3-68-76","DOIUrl":"https://doi.org/10.17073/0021-3438-2019-3-68-76","url":null,"abstract":"Alloy composition was developed and heat treatment conditions were selected to obtain an intensively dissolving magnesium alloy to be used as a ball plug under oil-well precommissioning conditions, i.e. to seal various well sections with further near-complete destruction of these plugs for a short time (up to 11 h). It was found that the reason of high dissolution rate of Mg alloy with a composition similar to high-strength ML6 is a higher nickel content (up to 0,19 %). The compounds of this element are located along the grain boundaries, and it leads to intense intercrystalline corrosion of the alloy in a medium containing chlorine ions. It is shown that an effective method for controlling the Mg alloy dissolution rate is to synthesize coatings on its surface with various thicknesses by plasma electrolytic treatment (PET) in aqueous solution containing 110 g/l of commercial water glass. This method allowed synthesizing coatings with a thickness from 10 to 41 μm on the experimental magnesium alloy with increased nickel concentrations (~ 0,19 %) in a short period of time (from 10 to 20 min) with low set AC current density (4 A/dm2) – galvanostatic mode of PET processes. Corrosion investigations were carried out in 3 % KCl aqueous solution at 93 ± 2 °C. PET coatings were obtained on the magnesium alloy using a capacitive unit. Corrosion tests conditions for materials used as ball plugs in oil well seals were similar to that cited in foreign researches.","PeriodicalId":14523,"journal":{"name":"Izvestiya Vuzov Tsvetnaya Metallurgiya (Proceedings of Higher Schools Nonferrous Metallurgy","volume":"27 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73938218","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 : 2019-06-19DOI: 10.17073/0021-3438-2019-3-55-67
O. Kanunnikova, V. Aksenova, B. Pushkarev, V. Ladyanov
The influence of domestic VNKh-L type nitrogen-containing corrosion inhibitors on the corrosion patterns of zinc coating on steel in a neutral environment was investigated. The paper aims to study the structure of the corroding zinc coating surface, as well as the influence of conditions simulating the degradation of inhibitors under actual application conditions on their protective properties. Mechanical activation in a ball planetary mill was used to simulate the thermal and deformation conditions of inhibitors. Zinc coating corrosion on steel was carried out in a sulfate-chloride environment simulating atmospheric corrosion and in borate buffer solution. The concentration of inhibitors in corrosion environments was 0,2 wt.%. The corroded surface morphology of the zinc coating was studied using the Philips SEM-515 scanning electron microscope (at an accelerating voltage of 10 kV) with an X-ray micro probe. Studies of the zinc coating corrosion rate on St 08 were carried out by the indirect measurement of corrosion resistance using the MONIKOR-1 corrosion meter. Borate buffer solution (Na2B4O7 + H3BO3, pH = 6,6) and the solution simulating atmospheric corrosion (NaCl + + Na2SO4, pH = 6,0) were used as corrosive environments. The corrosion rate of samples in corrosive environments without inhibitors was taken as 1. Exposure time of each sample in corrosive environments was 3 h. The chemical composition of corrosion products was studied by mirror reflection in the IR range. The IR spectra of metal plate surfaces were recorded on the FSM-1202 IR Fourier spectrometer in a wavelength range of 450–4000 cm–1 with a resolution of 2 cm–1 and an accumulation of 100 scans. A mirror reflection attachment with a 10° angle of incidence was used to obtain reflection spectra. The zinc coating corrosion rate in sulfate-chloride and borate environments in the presence of inhibitors based on benzotriazole and cyclohexylamine was virtually not reduced compared to the corrosion rate in the same environments without inhibitors. When both initial and mechanically activated inhibitors based on morpholine and benzotriazole are added to the corrosion environment, the iron corrosion rate decreases compared to the corrosion rate in the same environments without inhibitors. In the presence of initial and mechanically activated inhibitors of both groups, pitting corrosion of the zinc coating in the studied corrosion environments is observed. At the same time, the pitting depth under corrosion conditions is less than the zinc coating thickness.
{"title":"Peculiarities of zinc coating corrosion in neutral environments with inhibitors based on benzotriazole, cyclohexylamine and morpholine","authors":"O. Kanunnikova, V. Aksenova, B. Pushkarev, V. Ladyanov","doi":"10.17073/0021-3438-2019-3-55-67","DOIUrl":"https://doi.org/10.17073/0021-3438-2019-3-55-67","url":null,"abstract":"The influence of domestic VNKh-L type nitrogen-containing corrosion inhibitors on the corrosion patterns of zinc coating on steel in a neutral environment was investigated. The paper aims to study the structure of the corroding zinc coating surface, as well as the influence of conditions simulating the degradation of inhibitors under actual application conditions on their protective properties. Mechanical activation in a ball planetary mill was used to simulate the thermal and deformation conditions of inhibitors. Zinc coating corrosion on steel was carried out in a sulfate-chloride environment simulating atmospheric corrosion and in borate buffer solution. The concentration of inhibitors in corrosion environments was 0,2 wt.%. The corroded surface morphology of the zinc coating was studied using the Philips SEM-515 scanning electron microscope (at an accelerating voltage of 10 kV) with an X-ray micro probe. Studies of the zinc coating corrosion rate on St 08 were carried out by the indirect measurement of corrosion resistance using the MONIKOR-1 corrosion meter. Borate buffer solution (Na2B4O7 + H3BO3, pH = 6,6) and the solution simulating atmospheric corrosion (NaCl + + Na2SO4, pH = 6,0) were used as corrosive environments. The corrosion rate of samples in corrosive environments without inhibitors was taken as 1. Exposure time of each sample in corrosive environments was 3 h. The chemical composition of corrosion products was studied by mirror reflection in the IR range. The IR spectra of metal plate surfaces were recorded on the FSM-1202 IR Fourier spectrometer in a wavelength range of 450–4000 cm–1 with a resolution of 2 cm–1 and an accumulation of 100 scans. A mirror reflection attachment with a 10° angle of incidence was used to obtain reflection spectra. The zinc coating corrosion rate in sulfate-chloride and borate environments in the presence of inhibitors based on benzotriazole and cyclohexylamine was virtually not reduced compared to the corrosion rate in the same environments without inhibitors. When both initial and mechanically activated inhibitors based on morpholine and benzotriazole are added to the corrosion environment, the iron corrosion rate decreases compared to the corrosion rate in the same environments without inhibitors. In the presence of initial and mechanically activated inhibitors of both groups, pitting corrosion of the zinc coating in the studied corrosion environments is observed. At the same time, the pitting depth under corrosion conditions is less than the zinc coating thickness.","PeriodicalId":14523,"journal":{"name":"Izvestiya Vuzov Tsvetnaya Metallurgiya (Proceedings of Higher Schools Nonferrous Metallurgy","volume":"54 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90388672","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 : 2019-06-18DOI: 10.17073/0021-3438-2019-3-4-11
A. Kolesnikov, I. Tsyganova
We studied a number of models for the description of copper reduction by fine zinc powder in aqueous solutions. The experimentswere carried out in devices with a magnetic stirrer at mixing speeds of 40–150 rpm and temperatures of 15–50 °C. We investigated the influence exerted on the process by macromolecular flocculants such as non-ionic magnafloc 333, cationic besflok 6645 and anionic besfloc 4034. Under industrial conditions, these flocculants are used at the hydrolytic solution purification stage and then they are fed to cementing purification together with the clarified solution. Aqueous flocculant solutions of 2,5 g/l containing 2–4 g/l of zinc dust and 50–200 mg/l of flocculant were used in the experiments. Copper content in the initial and final solutions was quantitatively determined by spectrophotometric analysis with the preliminary copper transfer to the ammonia complex. Experiment duration varied from 1 to 8 min. The degree of copper reduction from solutions was 10–90 %. It was found that at low mixing rates the process kinetics can be described by the kinetic equation of the first order. At high speeds, the kinetics of the studied heterogeneous reactionwith added flocculants is more adequately described by the velocity change equation as a square root of the process duration. It wasshown that the highest constant of cementation rate is observed in experiments without the addition of surfactants. Anionic flocculant slows down the cementation process to a lesser extent than cationic one, which is consistent with the theory of electrochemical processes and shows that the discharge of copper cations under these conditions limits the cementation process. Regularities revealed in the studied process remain as temperature increases. It was noted that the addition of high-molecular substances with a relative molecular mass of 20 million in an amount of 50–200 mg/l inhibit the cementation process. This fact must be taken into account in industrial conditions where cementing purification from copper and other impurities is carried out from flocculant-containing solutions.
{"title":"Investigation of flocculant influence on the kinetic parameters of copper recovery in aqueous solution with metal zinc","authors":"A. Kolesnikov, I. Tsyganova","doi":"10.17073/0021-3438-2019-3-4-11","DOIUrl":"https://doi.org/10.17073/0021-3438-2019-3-4-11","url":null,"abstract":"We studied a number of models for the description of copper reduction by fine zinc powder in aqueous solutions. The experimentswere carried out in devices with a magnetic stirrer at mixing speeds of 40–150 rpm and temperatures of 15–50 °C. We investigated the influence exerted on the process by macromolecular flocculants such as non-ionic magnafloc 333, cationic besflok 6645 and anionic besfloc 4034. Under industrial conditions, these flocculants are used at the hydrolytic solution purification stage and then they are fed to cementing purification together with the clarified solution. Aqueous flocculant solutions of 2,5 g/l containing 2–4 g/l of zinc dust and 50–200 mg/l of flocculant were used in the experiments. Copper content in the initial and final solutions was quantitatively determined by spectrophotometric analysis with the preliminary copper transfer to the ammonia complex. Experiment duration varied from 1 to 8 min. The degree of copper reduction from solutions was 10–90 %. It was found that at low mixing rates the process kinetics can be described by the kinetic equation of the first order. At high speeds, the kinetics of the studied heterogeneous reactionwith added flocculants is more adequately described by the velocity change equation as a square root of the process duration. It wasshown that the highest constant of cementation rate is observed in experiments without the addition of surfactants. Anionic flocculant slows down the cementation process to a lesser extent than cationic one, which is consistent with the theory of electrochemical processes and shows that the discharge of copper cations under these conditions limits the cementation process. Regularities revealed in the studied process remain as temperature increases. It was noted that the addition of high-molecular substances with a relative molecular mass of 20 million in an amount of 50–200 mg/l inhibit the cementation process. This fact must be taken into account in industrial conditions where cementing purification from copper and other impurities is carried out from flocculant-containing solutions.","PeriodicalId":14523,"journal":{"name":"Izvestiya Vuzov Tsvetnaya Metallurgiya (Proceedings of Higher Schools Nonferrous Metallurgy","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75040695","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 : 2019-06-18DOI: 10.17073/0021-3438-2019-3-30-35
S. Pilipenko
The paper provides the results of studying the effect of technological factors of the cold pipe rolling process on the changingof Q-factor distribution along the deformation cone. The Q-factor value, which is the relationship between actual deformation on the wall thickness and actual deformation on the pipe mean diameter, and the pattern of its distribution along the deformation cone are controlledvalues when rolling pipes from titanium and zirconium alloys of a certain range. The Q-factor defines whether metal grains will be oriented radially or tangentially. It is desirable that Q-factor f luctuate around its definite value with low amplitude along the entire deformation cone. It is determined that the method used to calculate the pipe wall thickness distribution along the deformation cone has a significant effect on the change in the Q-factor distribution along the deformation cone. The advantages of using mandrels with a curvilinear generatrix of the working surface profile are confirmed. Dependences ascertained in the article can be used to calculate the schedules of rolling and calibration of cold pilgering mill tools.
{"title":"Analysis of the influence of cold pipe rolling technological factors on the change in Q-factor distribution along the deformation cone","authors":"S. Pilipenko","doi":"10.17073/0021-3438-2019-3-30-35","DOIUrl":"https://doi.org/10.17073/0021-3438-2019-3-30-35","url":null,"abstract":"The paper provides the results of studying the effect of technological factors of the cold pipe rolling process on the changingof Q-factor distribution along the deformation cone. The Q-factor value, which is the relationship between actual deformation on the wall thickness and actual deformation on the pipe mean diameter, and the pattern of its distribution along the deformation cone are controlledvalues when rolling pipes from titanium and zirconium alloys of a certain range. The Q-factor defines whether metal grains will be oriented radially or tangentially. It is desirable that Q-factor f luctuate around its definite value with low amplitude along the entire deformation cone. It is determined that the method used to calculate the pipe wall thickness distribution along the deformation cone has a significant effect on the change in the Q-factor distribution along the deformation cone. The advantages of using mandrels with a curvilinear generatrix of the working surface profile are confirmed. Dependences ascertained in the article can be used to calculate the schedules of rolling and calibration of cold pilgering mill tools.","PeriodicalId":14523,"journal":{"name":"Izvestiya Vuzov Tsvetnaya Metallurgiya (Proceedings of Higher Schools Nonferrous Metallurgy","volume":"75 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86271041","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 : 2019-04-12DOI: 10.17073/0021-3438-2019-2-58-64
G. Klevtsov, R. Valiev, I. Semenova, N. Klevtsova, V. Danilov, M. Linderov, S. Zasypkin
Данная работа посвящена изучению сопротивления многоцикловой усталости ультрамелкозернистого (УМЗ) сплава ВТ6, полученного равноканальным угловым прессованием в сочетании с последующей экструзией и отжигом. Усталостным испытаниям кручением с вращением в условиях симметричного цикла нагружения подвергались образцы из сплава ВТ6 с бимодальной (глобулярно-пластинчатой) и УМЗ структурой. Показано, что предел выносливости УМЗ сплава был на 40% выше, чем усталостная прочность сплава с бимодальной структурой. Выявлены основные различия в поверхности разрушения образцов, обсуждается влияние УМЗ структуры на сопротивление материала зарождению и распространению усталостных трещин.
{"title":"Effect of ultrafine-grained structure on kinetics and mechanism of VT6 titanium alloy fatigue failure","authors":"G. Klevtsov, R. Valiev, I. Semenova, N. Klevtsova, V. Danilov, M. Linderov, S. Zasypkin","doi":"10.17073/0021-3438-2019-2-58-64","DOIUrl":"https://doi.org/10.17073/0021-3438-2019-2-58-64","url":null,"abstract":"Данная работа посвящена изучению сопротивления многоцикловой усталости ультрамелкозернистого (УМЗ) сплава ВТ6, полученного равноканальным угловым прессованием в сочетании с последующей экструзией и отжигом. Усталостным испытаниям кручением с вращением в условиях симметричного цикла нагружения подвергались образцы из сплава ВТ6 с бимодальной (глобулярно-пластинчатой) и УМЗ структурой. Показано, что предел выносливости УМЗ сплава был на 40% выше, чем усталостная прочность сплава с бимодальной структурой. Выявлены основные различия в поверхности разрушения образцов, обсуждается влияние УМЗ структуры на сопротивление материала зарождению и распространению усталостных трещин.","PeriodicalId":14523,"journal":{"name":"Izvestiya Vuzov Tsvetnaya Metallurgiya (Proceedings of Higher Schools Nonferrous Metallurgy","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81025213","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 : 2019-04-12DOI: 10.17073/0021-3438-2019-2-65-74
V. Shumskiy, N. Kulenova, Zh. S. Onalbayeva, Z. Akhmetvaliyeva, S. Mamyachenkov
The results of model studies on the possibility of reducing energy costs and carbon dioxide emissions during the Waelz processing of oxidized zinc-containing material in waelz kilns are presented. The studies were carried out using a specialized software product METSIM widely known in the world practice of metallurgical process and production modeling that allows analyzing the effect of changes in technological modes on the final results of the process. Model calculations showed that the greatest decrease in specific energy consumption and CO 2 emissions is observed when using blast air heated to 200 °C with an increase in its flow rate from 1000 to 7000 n.m 3 /h and concomitant decrease in atmospheric air suction. The estimated reduction in the specific costs of carbon and CO 2 emissions amounted to 30,2—35,5 %, and the total specific cost of energy carriers — 28—32 %. At the same time, blast air heating to 200 °C in the heat exchanger of the recovery boiler does not require additional energy inputs, in contrast to the use of oxygen blast with the cost of electricity for producing oxygen. Intensification of the waelz process using additional oxygen blasting (or air blast enrichment with oxygen) and heated blast air supply with concomitant decrease in air suction into the furnace from the atmosphere leads not only to a decrease in the specific consumption of the carbon energy carrier, but also to an increase in the degree of carbon utilization. The maximum estimated increase in the degree of carbon utilization was 6,2 rel.% — from 60,3 % on cold air blast without oxygen to 66,5 % on an air-oxygen blast (7000 n.m 3 /h of air and 185 n.m 3 /h of oxygen) heated up to 200 °C without atmospheric air. Maintaining optimal oxidation-reduction and thermal modes of the process requires correct regulation of the kiln draft mode taking into account atmospheric air suction in the unloading head of the kiln. Uncoordinated changes in the specific consumptions of charge, carbon, blast air and rarefaction in the dust chamber lead to a concomitant decrease in the extraction of zinc to sublimates and increase in its losses with clinker.
{"title":"Investigation of the possibility of carbon dioxide reduction by Waelz processing of oxidized zinc-containing material","authors":"V. Shumskiy, N. Kulenova, Zh. S. Onalbayeva, Z. Akhmetvaliyeva, S. Mamyachenkov","doi":"10.17073/0021-3438-2019-2-65-74","DOIUrl":"https://doi.org/10.17073/0021-3438-2019-2-65-74","url":null,"abstract":"The results of model studies on the possibility of reducing energy costs and carbon dioxide emissions during the Waelz processing of oxidized zinc-containing material in waelz kilns are presented. The studies were carried out using a specialized software product METSIM widely known in the world practice of metallurgical process and production modeling that allows analyzing the effect of changes in technological modes on the final results of the process. Model calculations showed that the greatest decrease in specific energy consumption and CO 2 emissions is observed when using blast air heated to 200 °C with an increase in its flow rate from 1000 to 7000 n.m 3 /h and concomitant decrease in atmospheric air suction. The estimated reduction in the specific costs of carbon and CO 2 emissions amounted to 30,2—35,5 %, and the total specific cost of energy carriers — 28—32 %. At the same time, blast air heating to 200 °C in the heat exchanger of the recovery boiler does not require additional energy inputs, in contrast to the use of oxygen blast with the cost of electricity for producing oxygen. Intensification of the waelz process using additional oxygen blasting (or air blast enrichment with oxygen) and heated blast air supply with concomitant decrease in air suction into the furnace from the atmosphere leads not only to a decrease in the specific consumption of the carbon energy carrier, but also to an increase in the degree of carbon utilization. The maximum estimated increase in the degree of carbon utilization was 6,2 rel.% — from 60,3 % on cold air blast without oxygen to 66,5 % on an air-oxygen blast (7000 n.m 3 /h of air and 185 n.m 3 /h of oxygen) heated up to 200 °C without atmospheric air. Maintaining optimal oxidation-reduction and thermal modes of the process requires correct regulation of the kiln draft mode taking into account atmospheric air suction in the unloading head of the kiln. Uncoordinated changes in the specific consumptions of charge, carbon, blast air and rarefaction in the dust chamber lead to a concomitant decrease in the extraction of zinc to sublimates and increase in its losses with clinker.","PeriodicalId":14523,"journal":{"name":"Izvestiya Vuzov Tsvetnaya Metallurgiya (Proceedings of Higher Schools Nonferrous Metallurgy","volume":"130 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77976296","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 : 2019-04-12DOI: 10.17073/0021-3438-2019-2-4-12
N. Khrunina, K. Prokhorov
The paper considers the results obtained in the study of the prospective gold-silver complex deposit at the Eriksky ore cluster (Khabarovsk Territory) with refractory pofycomponent ores. Energy dispersive, atomic emission, grain size and dispersive analysis of rock samples were carried out. Samples contained microelements of a wide range including gold, silver, bismuth, cobalt, chromium, manganese, molybdenum, nickel, lead, vanadium, tungsten, zinc, copper, etc. It was found that pofycomponent and dispersed composition of mineral raw materials at the deposit defines it as a complex object to extract valuable components. It was proposed to use systems based on methods that reduce consumption of reagents to address the issue of precious metal extraction with more environmentally and technologically efficient tools. It is achieved by creating conditions for a sustainable process of preparation for leaching of mineral components containing gold and platinum through destruction of the mineral component of refractory polycomponent ores by increasing micro disintegration fields using ultrasound. Providing sustainability of mineral crystal lattice destruction by regrinding the solid phase formed during cavitation is a fundamental factor when preparing for the extraction of microparticles of valuable components.
{"title":"Improving processes of gold-silver refractory ores treatment at the complex deposit of precious metals","authors":"N. Khrunina, K. Prokhorov","doi":"10.17073/0021-3438-2019-2-4-12","DOIUrl":"https://doi.org/10.17073/0021-3438-2019-2-4-12","url":null,"abstract":"The paper considers the results obtained in the study of the prospective gold-silver complex deposit at the Eriksky ore cluster (Khabarovsk Territory) with refractory pofycomponent ores. Energy dispersive, atomic emission, grain size and dispersive analysis of rock samples were carried out. Samples contained microelements of a wide range including gold, silver, bismuth, cobalt, chromium, manganese, molybdenum, nickel, lead, vanadium, tungsten, zinc, copper, etc. It was found that pofycomponent and dispersed composition of mineral raw materials at the deposit defines it as a complex object to extract valuable components. It was proposed to use systems based on methods that reduce consumption of reagents to address the issue of precious metal extraction with more environmentally and technologically efficient tools. It is achieved by creating conditions for a sustainable process of preparation for leaching of mineral components containing gold and platinum through destruction of the mineral component of refractory polycomponent ores by increasing micro disintegration fields using ultrasound. Providing sustainability of mineral crystal lattice destruction by regrinding the solid phase formed during cavitation is a fundamental factor when preparing for the extraction of microparticles of valuable components.","PeriodicalId":14523,"journal":{"name":"Izvestiya Vuzov Tsvetnaya Metallurgiya (Proceedings of Higher Schools Nonferrous Metallurgy","volume":"43 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79418790","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 : 2019-04-12DOI: 10.17073/0021-3438-2019-2-51-57
К. Н. Вдовин, Г. А. Дубский, В. Б. Деев, Л. Г. Егорова, А. А. Нефедьев, Е. С. Прусов
The paper presents an investigation of the structure and mechanical properties of A356.0 and A413.1 cast aluminum alloys subjected to a pulsed magnetic field of different saturation during crystallization. It was established during experiments that samples contain in their composition two phases that crystallize at certain temperature intervals and do not change even when magnetic field is applied to the crystallizing melt. A temperature gradient was found between the mold wall and the outer wall of the crucible for both alloys, which varies between <14,3 and 16,0 °C/mm, as well as the crystallization time of each phase. Using thermophysical approaches, a linear crystallization rate was found for both alloys. It was determined that it decreases with decreasing temperature gradient, while the crystallization time of phases increases. It was found that the magnetic field changes the distribution of dendrites over the volume of A356.0 and A413.1 alloys, as well as their dimensions and orientation in the section plane. With an increase in the magnetic field induction amplitude, a finer structure is formed in the а -phase of the alloy, which uniformly fills the section plane, and this is reflected in its mechanical properties. The hardness of the investigated alloys increases with an increase in the amplitude of the pulsed magnetic field induction by approximately 8—10 % for both alloys due to the refinement of the dendritic structure and a more even distribution of а -solid solution dendrites over the volume of the crystallizing sample. In addition, the magnetic field affects the ultimate tensile strength, and practically does not change the value of relative elongation under uniaxial tension of the investigated A356.0 and A413.1 alloys.
{"title":"Influence of magnetic field on structure formation at crystallization and physical-mechanical properties of aluminum alloys","authors":"К. Н. Вдовин, Г. А. Дубский, В. Б. Деев, Л. Г. Егорова, А. А. Нефедьев, Е. С. Прусов","doi":"10.17073/0021-3438-2019-2-51-57","DOIUrl":"https://doi.org/10.17073/0021-3438-2019-2-51-57","url":null,"abstract":"The paper presents an investigation of the structure and mechanical properties of A356.0 and A413.1 cast aluminum alloys subjected to a pulsed magnetic field of different saturation during crystallization. It was established during experiments that samples contain in their composition two phases that crystallize at certain temperature intervals and do not change even when magnetic field is applied to the crystallizing melt. A temperature gradient was found between the mold wall and the outer wall of the crucible for both alloys, which varies between <14,3 and 16,0 °C/mm, as well as the crystallization time of each phase. Using thermophysical approaches, a linear crystallization rate was found for both alloys. It was determined that it decreases with decreasing temperature gradient, while the crystallization time of phases increases. It was found that the magnetic field changes the distribution of dendrites over the volume of A356.0 and A413.1 alloys, as well as their dimensions and orientation in the section plane. With an increase in the magnetic field induction amplitude, a finer structure is formed in the а -phase of the alloy, which uniformly fills the section plane, and this is reflected in its mechanical properties. The hardness of the investigated alloys increases with an increase in the amplitude of the pulsed magnetic field induction by approximately 8—10 % for both alloys due to the refinement of the dendritic structure and a more even distribution of а -solid solution dendrites over the volume of the crystallizing sample. In addition, the magnetic field affects the ultimate tensile strength, and practically does not change the value of relative elongation under uniaxial tension of the investigated A356.0 and A413.1 alloys.","PeriodicalId":14523,"journal":{"name":"Izvestiya Vuzov Tsvetnaya Metallurgiya (Proceedings of Higher Schools Nonferrous Metallurgy","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79468959","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：