Pub Date : 2022-04-09DOI: 10.17073/0368-0797-2022-3-209-215
R. V. Kuznetsov, V. Kormyshev, V. Gromov, Y. Ivanov, Yu. A. Shlyarova
Quantitative transformations of the structure at a depth of 0, 2, 5, 10 mm along the central and symmetry axis of the fillet of long differentially quenched rails head after extremely long-term operation (passed tonnage of 1770 mln. gross tons) were identified at macro-, micro- and nanoscale levels by methods of optical, scanning and transmission electron diffraction microscopy. At a macroscale level, the numerous shallow parallel cracks of contact fatigue are detected on the surface of working fillet, and on the surface of inoperative fillet there are only small spallings. The lateral wear of the rail was 2.5 mm and the vertical wear was 2 mm. Microstructure of the rail head metal corresponds to the requirements of standards and specifications of the Russian Railways. At microscale level, the transformation of cementite plates was established by cutting it with moving dislocations and dissolving with the escape of carbon to the dislocation lines, low- and high-angle boundaries. A decrease in microstructure dispersion is noted with a distance from the tread surface. At the nanoscale level, subgrain structure formed in the surface layers (subgrain size 110 – 200 μm) contains nanosized cementite particles (25 – 60 nm) localized at the joints and along the subgrain boundaries. It is supposed that this type of structure is formed as a result of dynamic recrystallization under megaplastic deformation in the process of extremely long-term operation of rails. The content of subgrain structure in the fillet layer is five-fold higher than that in surface layer of the tread surface. It was established that during operation, the transformation of lamellar perlite along the central axis of the head proceeds more slowly than along the symmetry axis of the fillet.
{"title":"Transformation of structural-phase states in rail head at extremely long-term operation","authors":"R. V. Kuznetsov, V. Kormyshev, V. Gromov, Y. Ivanov, Yu. A. Shlyarova","doi":"10.17073/0368-0797-2022-3-209-215","DOIUrl":"https://doi.org/10.17073/0368-0797-2022-3-209-215","url":null,"abstract":"Quantitative transformations of the structure at a depth of 0, 2, 5, 10 mm along the central and symmetry axis of the fillet of long differentially quenched rails head after extremely long-term operation (passed tonnage of 1770 mln. gross tons) were identified at macro-, micro- and nanoscale levels by methods of optical, scanning and transmission electron diffraction microscopy. At a macroscale level, the numerous shallow parallel cracks of contact fatigue are detected on the surface of working fillet, and on the surface of inoperative fillet there are only small spallings. The lateral wear of the rail was 2.5 mm and the vertical wear was 2 mm. Microstructure of the rail head metal corresponds to the requirements of standards and specifications of the Russian Railways. At microscale level, the transformation of cementite plates was established by cutting it with moving dislocations and dissolving with the escape of carbon to the dislocation lines, low- and high-angle boundaries. A decrease in microstructure dispersion is noted with a distance from the tread surface. At the nanoscale level, subgrain structure formed in the surface layers (subgrain size 110 – 200 μm) contains nanosized cementite particles (25 – 60 nm) localized at the joints and along the subgrain boundaries. It is supposed that this type of structure is formed as a result of dynamic recrystallization under megaplastic deformation in the process of extremely long-term operation of rails. The content of subgrain structure in the fillet layer is five-fold higher than that in surface layer of the tread surface. It was established that during operation, the transformation of lamellar perlite along the central axis of the head proceeds more slowly than along the symmetry axis of the fillet.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"236 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76833152","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 : 2022-04-08DOI: 10.17073/0368-0797-2022-3-163-169
N. M. Vavilkin, А. S. Budnikov
A technique was developed for the numerical analysis of the thermal state of long mandrels of a three-roll rolling mill using modern computer simulation software. The initial and boundary conditions were determined taking into account the peculiarities of rolling in a three-roll screw rolling mill on a long mandrel. The authors carried out a qualitative assessment of the thermal state of a long mandrel by means of visualized representation and established its significant inhomogeneity. Influence of the rolling temperature and diameter of the long mandrel were revealed. Small diameter mandrels are heated to higher temperatures (577 °C) with a significantly lower gradient between the axial zone and the surface. An increase in the mandrel diameter to 154 mm lowers the temperature of the outer surface to 530 °C and increases temperature gradient in the near-surface layers up to 18 °C/mm. So the temperature in the near-surface layers for a mandrel of 154 mm at a distance of 10 – 15 mm from the surface decreases from 530 °C to 315 °C. Features of the temperature field in the cross section were established taking into account thermal interaction of the sleeve with the mandrel in the zone of contact with hot metal and in gaps between the rolls. Temperature of the near-surface layers in the contact zone is 30 °C higher than in the gaps. Dependences of temperature of the cross-section characteristic points on the rolling time were determined, it has been established that in the first two seconds there is an intense growth according to the parabolic, and then according to the linear laws. Temperature of the central layers with a radius of 50 mm increases with a much lower intensity, by about 100 °С during the entire period of rolling, while during the same time, the near-surface layers are heated by 300 – 400 °С.
{"title":"Investigation of thermal state of long mandrels on three-roll rolling mill","authors":"N. M. Vavilkin, А. S. Budnikov","doi":"10.17073/0368-0797-2022-3-163-169","DOIUrl":"https://doi.org/10.17073/0368-0797-2022-3-163-169","url":null,"abstract":"A technique was developed for the numerical analysis of the thermal state of long mandrels of a three-roll rolling mill using modern computer simulation software. The initial and boundary conditions were determined taking into account the peculiarities of rolling in a three-roll screw rolling mill on a long mandrel. The authors carried out a qualitative assessment of the thermal state of a long mandrel by means of visualized representation and established its significant inhomogeneity. Influence of the rolling temperature and diameter of the long mandrel were revealed. Small diameter mandrels are heated to higher temperatures (577 °C) with a significantly lower gradient between the axial zone and the surface. An increase in the mandrel diameter to 154 mm lowers the temperature of the outer surface to 530 °C and increases temperature gradient in the near-surface layers up to 18 °C/mm. So the temperature in the near-surface layers for a mandrel of 154 mm at a distance of 10 – 15 mm from the surface decreases from 530 °C to 315 °C. Features of the temperature field in the cross section were established taking into account thermal interaction of the sleeve with the mandrel in the zone of contact with hot metal and in gaps between the rolls. Temperature of the near-surface layers in the contact zone is 30 °C higher than in the gaps. Dependences of temperature of the cross-section characteristic points on the rolling time were determined, it has been established that in the first two seconds there is an intense growth according to the parabolic, and then according to the linear laws. Temperature of the central layers with a radius of 50 mm increases with a much lower intensity, by about 100 °С during the entire period of rolling, while during the same time, the near-surface layers are heated by 300 – 400 °С.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"82 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90818672","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 : 2022-04-08DOI: 10.17073/0368-0797-2022-3-188-189
M. S. Derevyanko, A. V. Kondrat'ev
A new approach to obtain amorphous oxides was investigated both theoretically and experimentally using X-ray diffraction (XRD) and electron probe microanalysis (EPMA) techniques. In this work, the conventional sol-gel method was modified by the addition of malic acid as an oxidizing agent and successfully applied to obtain two oxides Al2O3 & Fe2O3 with the amorphous structure. The results of the modified sol-gel method were compared to those obtained by thermal decomposition of corresponding salts, and the advantage of new technique was clearly demonstrated. Thermal stability of the obtained amorphous oxides was examined by the differential scanning calorimetry (DSC). It was found that amorphous Al2O3 is stable up to 790 – 810 °C, while amorphous Fe2O3 recrystallises at about 160 – 180 °C, depending on the heating rate.
{"title":"Phase transformations and thermodynamic properties of oxide systems","authors":"M. S. Derevyanko, A. V. Kondrat'ev","doi":"10.17073/0368-0797-2022-3-188-189","DOIUrl":"https://doi.org/10.17073/0368-0797-2022-3-188-189","url":null,"abstract":"A new approach to obtain amorphous oxides was investigated both theoretically and experimentally using X-ray diffraction (XRD) and electron probe microanalysis (EPMA) techniques. In this work, the conventional sol-gel method was modified by the addition of malic acid as an oxidizing agent and successfully applied to obtain two oxides Al2O3 & Fe2O3 with the amorphous structure. The results of the modified sol-gel method were compared to those obtained by thermal decomposition of corresponding salts, and the advantage of new technique was clearly demonstrated. Thermal stability of the obtained amorphous oxides was examined by the differential scanning calorimetry (DSC). It was found that amorphous Al2O3 is stable up to 790 – 810 °C, while amorphous Fe2O3 recrystallises at about 160 – 180 °C, depending on the heating rate.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"230 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84916607","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 : 2022-04-08DOI: 10.17073/0368-0797-2022-3-170-178
М. V. Kleonovskii, O. Sheshukov, M. Mikheenkov, Е. Y. Lozovaya
Ferrous metallurgy enterprises continuously fill dumps with steelmaking and blast furnace sludge with high zinc content. Sludge occupying significant territories of enterprises is not involved in production and harms the environment. Since zinc leads to the formation of deposits in the blast furnace, manufacturers cannot involve this sludge in sinter processing. In addition, working with sludge can lead to problems such as decrease in iron content in the sinter, decrease in productivity of sintering machines, and increase in fluctuations in the sinter chemical composition. At the same time, zinc-containing sludge can become a valuable secondary product. Zinc remains a scarce metal, which encourages the development of technologies for processing zinc-containing materials. Extraction of zinc from sludge is difficult because it is not in oxide, but in sulfate or sulfide forms. In this paper, the possibilities of zinc extraction from sludge using the FactSage software package are evaluated. The authors present results of thermodynamic calculations of the possibility of zinc extraction from four types of sludge from two Russian ferrous metallurgical plants – EVRAZ NTMK and MECHEL. The data of chemical and phase analyses of this sludge are considered, as well as simulated graphs of zinc extraction dependencies from them. The graphs were built on basis of the received data from FactSage package. Addition of the reducing agent to the sludge varied, as well as temperature of the process. In addition, the possibility of abandoning carbon as a reducing agent was evaluated. To save the reducing agent, an optimal mixture of the company’s sludge was selected, in which coke consumption can be minimized.
{"title":"Thermodynamic modeling of zinc recovery from ferrous metallurgy sludge","authors":"М. V. Kleonovskii, O. Sheshukov, M. Mikheenkov, Е. Y. Lozovaya","doi":"10.17073/0368-0797-2022-3-170-178","DOIUrl":"https://doi.org/10.17073/0368-0797-2022-3-170-178","url":null,"abstract":"Ferrous metallurgy enterprises continuously fill dumps with steelmaking and blast furnace sludge with high zinc content. Sludge occupying significant territories of enterprises is not involved in production and harms the environment. Since zinc leads to the formation of deposits in the blast furnace, manufacturers cannot involve this sludge in sinter processing. In addition, working with sludge can lead to problems such as decrease in iron content in the sinter, decrease in productivity of sintering machines, and increase in fluctuations in the sinter chemical composition. At the same time, zinc-containing sludge can become a valuable secondary product. Zinc remains a scarce metal, which encourages the development of technologies for processing zinc-containing materials. Extraction of zinc from sludge is difficult because it is not in oxide, but in sulfate or sulfide forms. In this paper, the possibilities of zinc extraction from sludge using the FactSage software package are evaluated. The authors present results of thermodynamic calculations of the possibility of zinc extraction from four types of sludge from two Russian ferrous metallurgical plants – EVRAZ NTMK and MECHEL. The data of chemical and phase analyses of this sludge are considered, as well as simulated graphs of zinc extraction dependencies from them. The graphs were built on basis of the received data from FactSage package. Addition of the reducing agent to the sludge varied, as well as temperature of the process. In addition, the possibility of abandoning carbon as a reducing agent was evaluated. To save the reducing agent, an optimal mixture of the company’s sludge was selected, in which coke consumption can be minimized.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85130148","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 : 2022-04-08DOI: 10.17073/0368-0797-2022-3-154-162
A. A. Al’khimenko, A. Davydov, A. Khar’kov, S. Mushnikova, O. A. Khar’kov, O. Parmenova, A. A. Yakovitskii
The review describes methods of stress corrosion cracking (SCС) tests that implement various conditions for samples loading: at a constant static load or deformation, at a constant or increasing load of samples with a previously grown fatigue crack, with a slow strain rate. Such tests shall be carried out to determine the resistance of shipbuilding materials to be used in loaded ship structures in contact with seawater. Brief descriptions of the mechanism of stress corrosion cracking of steels and alloys are given. The necessity to carry out bench tests of steels and their welded joints, as well as models simulating individual units and elements of structures, is indicated. At this stage, conditions are ensured as close to operating conditions as possible due to exposure in various climatic zones of the world’s oceans (variations in temperature, chloride concentration, amount of dissolved oxygen, degree of biofouling, and their simultaneous impact). It is shown that during verification field tests (final stage) new materials promising for operation in marine conditions pass the final evaluation of corrosion resistance in the form of elements of ship structures and systems in the conditions of ship operation.
{"title":"Methods of corrosion testing used for development and commercial exploitation of new shipbuilding steels and alloys. Review. Part II. Corrosion cracking and field marine tests","authors":"A. A. Al’khimenko, A. Davydov, A. Khar’kov, S. Mushnikova, O. A. Khar’kov, O. Parmenova, A. A. Yakovitskii","doi":"10.17073/0368-0797-2022-3-154-162","DOIUrl":"https://doi.org/10.17073/0368-0797-2022-3-154-162","url":null,"abstract":"The review describes methods of stress corrosion cracking (SCС) tests that implement various conditions for samples loading: at a constant static load or deformation, at a constant or increasing load of samples with a previously grown fatigue crack, with a slow strain rate. Such tests shall be carried out to determine the resistance of shipbuilding materials to be used in loaded ship structures in contact with seawater. Brief descriptions of the mechanism of stress corrosion cracking of steels and alloys are given. The necessity to carry out bench tests of steels and their welded joints, as well as models simulating individual units and elements of structures, is indicated. At this stage, conditions are ensured as close to operating conditions as possible due to exposure in various climatic zones of the world’s oceans (variations in temperature, chloride concentration, amount of dissolved oxygen, degree of biofouling, and their simultaneous impact). It is shown that during verification field tests (final stage) new materials promising for operation in marine conditions pass the final evaluation of corrosion resistance in the form of elements of ship structures and systems in the conditions of ship operation.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"38 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85949407","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 : 2022-04-08DOI: 10.17073/0368-0797-2022-3-190-199
M. Kostina, A. Kudryashov, L. Rigina, S. Muradyan, O. Antonova, V. S. Kostina
The new casting austenitic Cr – Ni – Mn steel with 0.5 % N (grade 05Kh21AG15N8MFL) surpasses the casting steel of the 18Cr – 10 Ni type used for comparison in the entire range of climatic temperatures. In this part of the article, attention is paid to the particles of non-metallic inclusions (NMI) in the cast metal of nitrous steel as a factor that can affect the mechanical properties under static and impact loading at low temperatures. NMI in laboratory metal are globular oxysulfides, with SiO2 oxides in the central part and an outer layer formed by manganese sulfide MnS, with an average particle size of ~75 % up to 4 μm. It has been established that when testing casting steel for impact bending at –160 °C, these NMI do not serve as a source of crack initiation, do not contribute to their propagation and are in a fracture surface in isolated pits. Under tensile conditions at –110 °C, the yield strength of nitrogen containing steel increases by more than 1.7 times in comparison with the properties at +20 °C; ductility does not decrease when cooled to –110 °C. In this case, NMI particles are strongly deformed due to the development of cracks in their oxide part, and even when NMI reaches the surface of the sample in working part in the neck zone, they do not serve as a source of crack initiation. Cracks at the boundary “NMI/ deforming metal” are not formed. Even with a random arrangement of particles in the form of chains along the axis of application of the tensile load, at a distance of 5 – 20 μm from each other, pores do not form around the particles and merge into a crack nucleus. The results obtained correlate with the literature data that NMI can act as stress relaxers in ductile steels.
{"title":"Cold resistance of new casting Cr – Mn – Ni – Mo – N steel. Part 2. Investigation of the factor of non-metallic inclusions particles under static and impact loading at low temperatures","authors":"M. Kostina, A. Kudryashov, L. Rigina, S. Muradyan, O. Antonova, V. S. Kostina","doi":"10.17073/0368-0797-2022-3-190-199","DOIUrl":"https://doi.org/10.17073/0368-0797-2022-3-190-199","url":null,"abstract":"The new casting austenitic Cr – Ni – Mn steel with 0.5 % N (grade 05Kh21AG15N8MFL) surpasses the casting steel of the 18Cr – 10 Ni type used for comparison in the entire range of climatic temperatures. In this part of the article, attention is paid to the particles of non-metallic inclusions (NMI) in the cast metal of nitrous steel as a factor that can affect the mechanical properties under static and impact loading at low temperatures. NMI in laboratory metal are globular oxysulfides, with SiO2 oxides in the central part and an outer layer formed by manganese sulfide MnS, with an average particle size of ~75 % up to 4 μm. It has been established that when testing casting steel for impact bending at –160 °C, these NMI do not serve as a source of crack initiation, do not contribute to their propagation and are in a fracture surface in isolated pits. Under tensile conditions at –110 °C, the yield strength of nitrogen containing steel increases by more than 1.7 times in comparison with the properties at +20 °C; ductility does not decrease when cooled to –110 °C. In this case, NMI particles are strongly deformed due to the development of cracks in their oxide part, and even when NMI reaches the surface of the sample in working part in the neck zone, they do not serve as a source of crack initiation. Cracks at the boundary “NMI/ deforming metal” are not formed. Even with a random arrangement of particles in the form of chains along the axis of application of the tensile load, at a distance of 5 – 20 μm from each other, pores do not form around the particles and merge into a crack nucleus. The results obtained correlate with the literature data that NMI can act as stress relaxers in ductile steels.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"56 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74142969","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 : 2022-03-17DOI: 10.17073/0368-0797-2022-2-134-136
R. V. Kuznetsov, O. Peregudov, V. V. Shlyarov
The article considers quantitative estimation of the relative carbon content in the structure elements of rail head after passed tonnage of 1411 and 1770 mln tons. In the initial state carbon is mainly located in cementite particles and after the operation the defects of crystal structure together with cementite are the places of carbon location. It is shown that the processes of carbon redistribution take place more intensive in surface layers up to 2 mm. Increase in passed tonnage is accompanied by intensive carbon movement on the defects of working fillet structure compared to the tread surface.
{"title":"Redistribution of carbon atoms in rails under ultra long-term operation","authors":"R. V. Kuznetsov, O. Peregudov, V. V. Shlyarov","doi":"10.17073/0368-0797-2022-2-134-136","DOIUrl":"https://doi.org/10.17073/0368-0797-2022-2-134-136","url":null,"abstract":"The article considers quantitative estimation of the relative carbon content in the structure elements of rail head after passed tonnage of 1411 and 1770 mln tons. In the initial state carbon is mainly located in cementite particles and after the operation the defects of crystal structure together with cementite are the places of carbon location. It is shown that the processes of carbon redistribution take place more intensive in surface layers up to 2 mm. Increase in passed tonnage is accompanied by intensive carbon movement on the defects of working fillet structure compared to the tread surface.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74742684","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 : 2022-03-17DOI: 10.17073/0368-0797-2022-2-145-147
A. G. Nikitin, M. E. Shabunov, P. Gerike
All industrial metallurgical enterprises produce and use milled materials obtained by crushing. In the global energy balance, the share of produced energy consumed for crushing is more than 5 %. This paper considers a scheme of the crusher with stops on a roll, the structure of which forms a complex stress state in a crushed piece under onetime action of normal and tangential stresses. It is shown that when generating a complex stress state in a fragmented piece of brittle material, the energy consumption is less by 30 – 40 % than when acting in a piece of linear normal stress. The authors developed a method for determining capacity of the drive electric motor of an energy-saving crusher with stop on a roll at design stage.
{"title":"Calculation of capacity of crusher with stops on a roll","authors":"A. G. Nikitin, M. E. Shabunov, P. Gerike","doi":"10.17073/0368-0797-2022-2-145-147","DOIUrl":"https://doi.org/10.17073/0368-0797-2022-2-145-147","url":null,"abstract":"All industrial metallurgical enterprises produce and use milled materials obtained by crushing. In the global energy balance, the share of produced energy consumed for crushing is more than 5 %. This paper considers a scheme of the crusher with stops on a roll, the structure of which forms a complex stress state in a crushed piece under onetime action of normal and tangential stresses. It is shown that when generating a complex stress state in a fragmented piece of brittle material, the energy consumption is less by 30 – 40 % than when acting in a piece of linear normal stress. The authors developed a method for determining capacity of the drive electric motor of an energy-saving crusher with stop on a roll at design stage.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79029213","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 : 2022-03-17DOI: 10.17073/0368-0797-2022-2-98-105
E. Shevchuk, V. Plotnikov, S. Makarov
The article presents data on studies of iron borides synthesis during induction heating to 1000 °C for 5 min of steel 20 samples with a coating from a charge containing Fe – H3BO3. Content of boric acid in the charge varied from 25 to 75 % wt. Charge in the experiments could be diluted with a solution of liquid glass in water with addition of small amount of ammonium hydroxide and coal. Study of the surface layer microhardness showed that during saturation of the surface layer of carbon steel 20 with boron, a macroscopically extensive diffusion zone 900 – 1000 μm in size is formed, in which the boride content gradually decreases when moving deeper into the matrix. Such a size of the diffusion zone indicates an anomalously high mass transfer during boriding of steel 20. Indeed, the calculated diffusion coefficient during boriding under induction conditions (about 1.35·10–9 m2/s) is two orders of magnitude higher than the diffusion coefficient in the classical boriding. X-ray studies showed that, under the considered conditions, Fe2B and FeB borides are synthesized, and a solid solution of boron in αiron is also formed. An analysis of phase composition of the diffusion zone structural components indicates that, from the surface to the matrix, formation of boride phases occurs in the following sequence: FeB → Fe2B → (αphase + B) → base metal. Microstructure of the diffusion zone consists of more or less pronounced layers consisting of FeB and Fe2B boride phases. On the whole, especially deep-ying regions of the diffusion zone are a composite material consisting of plastic α-phase and iron boride crystals. Crystals in FeB and Fe2B in the layer are oriented mainly perpendicular to the diffusion front. Perhaps, this is due to the rapid predominant growth of the boride phase under conditions of high diffusion mobility of boron atoms in one direction and hindered in others.
{"title":"Features of formation of diffusion zone obtained on steel 20 by boriding in induction furnace","authors":"E. Shevchuk, V. Plotnikov, S. Makarov","doi":"10.17073/0368-0797-2022-2-98-105","DOIUrl":"https://doi.org/10.17073/0368-0797-2022-2-98-105","url":null,"abstract":"The article presents data on studies of iron borides synthesis during induction heating to 1000 °C for 5 min of steel 20 samples with a coating from a charge containing Fe – H3BO3. Content of boric acid in the charge varied from 25 to 75 % wt. Charge in the experiments could be diluted with a solution of liquid glass in water with addition of small amount of ammonium hydroxide and coal. Study of the surface layer microhardness showed that during saturation of the surface layer of carbon steel 20 with boron, a macroscopically extensive diffusion zone 900 – 1000 μm in size is formed, in which the boride content gradually decreases when moving deeper into the matrix. Such a size of the diffusion zone indicates an anomalously high mass transfer during boriding of steel 20. Indeed, the calculated diffusion coefficient during boriding under induction conditions (about 1.35·10–9 m2/s) is two orders of magnitude higher than the diffusion coefficient in the classical boriding. X-ray studies showed that, under the considered conditions, Fe2B and FeB borides are synthesized, and a solid solution of boron in αiron is also formed. An analysis of phase composition of the diffusion zone structural components indicates that, from the surface to the matrix, formation of boride phases occurs in the following sequence: FeB → Fe2B → (αphase + B) → base metal. Microstructure of the diffusion zone consists of more or less pronounced layers consisting of FeB and Fe2B boride phases. On the whole, especially deep-ying regions of the diffusion zone are a composite material consisting of plastic α-phase and iron boride crystals. Crystals in FeB and Fe2B in the layer are oriented mainly perpendicular to the diffusion front. Perhaps, this is due to the rapid predominant growth of the boride phase under conditions of high diffusion mobility of boron atoms in one direction and hindered in others.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73175672","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 : 2022-03-16DOI: 10.17073/0368-0797-2022-2-85-91
G. Levshin
The article presents analysis of magnetization and heating of ferromagnetic charge in crucibles of induction furnaces of two types. In inductor furnaces, the charge is magnetized by a vertical electromagnetic flow, and in electromagnetic furnaces with a curved U-, C-, or O-shaped magnetic circuit (MPr) – by a horizontal flow. Knowledge of these largely general magnetization processes is insufficient. Bi magnetic induction in charge material is rather important. There are difficulties in determining this parameter during magnetization of a single piece of charge and other magnetic quantities associated with it: Bm induction and Nm strength of the demagnetizing field, N demagnetization coefficient, M magnetization, magnetic permeabilities of μi substance and μt body, km susceptibility, etc. Difficulties increase at magnetization, if it is a porous body with crucible volume of ~V t and a factor of filling with ferromagnetic pieces of this volume of Kv ≤ 0.5. It also creates a demagnetizing field with Bmt induction and Hmt strength. Beyond that, pores have an additional demagnetizing effect. Therefore, the induction Вiт in a porous body is less than the induction Вi in a solid one. To compare magnetization of ferromagnetic charge with horizontal and vertical flows with frequency of 50 Hz, modeling experiments were carried out with the samples of DSL08 unconsolidated shot from high-carbon steel (GOST 11964 – 83) with Kv ≈ 0.53. The samples were placed in the inductor and between the poles of a U-shaped core piece. Induction was measured by a cylindrical and flat probe unit of Sh1-15 militeslameter in air and in the sample. An advantage of electromagnetic furnace over an inductor one is more uniform distribution of Bi induction in charge and its significant excess (1.7 times) over the Be induction in a furnace working cavity, which indicates more efficient use of electromagnetic energy in this furnace during heating. The author proposed to control Вi induction when heating the charge by the ammeter-voltmeter method using measuring coil made of heat-resistant wire.
{"title":"Magnetization of ferromagnetic charge at induction heating","authors":"G. Levshin","doi":"10.17073/0368-0797-2022-2-85-91","DOIUrl":"https://doi.org/10.17073/0368-0797-2022-2-85-91","url":null,"abstract":"The article presents analysis of magnetization and heating of ferromagnetic charge in crucibles of induction furnaces of two types. In inductor furnaces, the charge is magnetized by a vertical electromagnetic flow, and in electromagnetic furnaces with a curved U-, C-, or O-shaped magnetic circuit (MPr) – by a horizontal flow. Knowledge of these largely general magnetization processes is insufficient. Bi magnetic induction in charge material is rather important. There are difficulties in determining this parameter during magnetization of a single piece of charge and other magnetic quantities associated with it: Bm induction and Nm strength of the demagnetizing field, N demagnetization coefficient, M magnetization, magnetic permeabilities of μi substance and μt body, km susceptibility, etc. Difficulties increase at magnetization, if it is a porous body with crucible volume of ~V t and a factor of filling with ferromagnetic pieces of this volume of Kv ≤ 0.5. It also creates a demagnetizing field with Bmt induction and Hmt strength. Beyond that, pores have an additional demagnetizing effect. Therefore, the induction Вiт in a porous body is less than the induction Вi in a solid one. To compare magnetization of ferromagnetic charge with horizontal and vertical flows with frequency of 50 Hz, modeling experiments were carried out with the samples of DSL08 unconsolidated shot from high-carbon steel (GOST 11964 – 83) with Kv ≈ 0.53. The samples were placed in the inductor and between the poles of a U-shaped core piece. Induction was measured by a cylindrical and flat probe unit of Sh1-15 militeslameter in air and in the sample. An advantage of electromagnetic furnace over an inductor one is more uniform distribution of Bi induction in charge and its significant excess (1.7 times) over the Be induction in a furnace working cavity, which indicates more efficient use of electromagnetic energy in this furnace during heating. The author proposed to control Вi induction when heating the charge by the ammeter-voltmeter method using measuring coil made of heat-resistant wire.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"61 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83538833","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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