Pub Date : 2023-06-06DOI: 10.17073/0368-0797-2023-2-177-183
G. Brover, E. E. Shcherbakova
The article presents the metal-physical studies results of the structure formation effects in surface layers in the hard alloys of the WC–Co system under extreme thermal and deformation effects of pulsed laser radiation. It is shown that the structural organization and properties of hard alloys VK6, VK8, VK10 upon radiation treatment with a power density of 175 MW/m2 are determined by state of the zones which are formed around carbide inclusions due to the various kinds of stresses appearance at the “carbide-bond” composition boundaries, including thermostrictive and phase stresses. The result is dissolution of the carbides boundary zones due to contact melting, which is accompanied by mutual mass transfer of atoms at the boundaries in the “carbide-bond” system with the possible formation of a thin amorphous-like super hard shell. These processes make it possible to create compositions in hard alloys with a set of differentiated properties specified by varying the laser treatment process parameters and composition of the starting materials. After laser alloying with a radiation power density of 200 MW/m2, temperature gradients and thermal stresses appearing in the surface layers of hard alloys with coatings (cobalt, nickel) contribute to convective mixing of the molten coating components and their penetration into the hard alloy to a depth of more than 20 μm. Simultaneously, despite the extremely short laser pulse time (10–3 s), mass transfer of tungsten, carbon and titanium atoms from the melted boundary zones of carbides to the adjacent bond zones with their hardening is possible in the irradiated zones. It was established that after high-temperature laser heating, carbides, in contrast to the initial ones, achieve a globular shape of grains. They are dispersed, and stoichiometric characteristics change in the local zones bordering the bond (the complex type carbide CoxWyCz is formed). As a result, due to these processes, the surface layers’ viscosity of hard alloys and the irradiated products performance increase. Compared to non-irradiated samples of hard alloy, the ultimate strength increases by 15 %, strength and durability – by 30 – 40 %.
{"title":"Structural organization and properties of surface layers of WC–Co hard alloys after pulsed laser processing","authors":"G. Brover, E. E. Shcherbakova","doi":"10.17073/0368-0797-2023-2-177-183","DOIUrl":"https://doi.org/10.17073/0368-0797-2023-2-177-183","url":null,"abstract":"The article presents the metal-physical studies results of the structure formation effects in surface layers in the hard alloys of the WC–Co system under extreme thermal and deformation effects of pulsed laser radiation. It is shown that the structural organization and properties of hard alloys VK6, VK8, VK10 upon radiation treatment with a power density of 175 MW/m2 are determined by state of the zones which are formed around carbide inclusions due to the various kinds of stresses appearance at the “carbide-bond” composition boundaries, including thermostrictive and phase stresses. The result is dissolution of the carbides boundary zones due to contact melting, which is accompanied by mutual mass transfer of atoms at the boundaries in the “carbide-bond” system with the possible formation of a thin amorphous-like super hard shell. These processes make it possible to create compositions in hard alloys with a set of differentiated properties specified by varying the laser treatment process parameters and composition of the starting materials. After laser alloying with a radiation power density of 200 MW/m2, temperature gradients and thermal stresses appearing in the surface layers of hard alloys with coatings (cobalt, nickel) contribute to convective mixing of the molten coating components and their penetration into the hard alloy to a depth of more than 20 μm. Simultaneously, despite the extremely short laser pulse time (10–3 s), mass transfer of tungsten, carbon and titanium atoms from the melted boundary zones of carbides to the adjacent bond zones with their hardening is possible in the irradiated zones. It was established that after high-temperature laser heating, carbides, in contrast to the initial ones, achieve a globular shape of grains. They are dispersed, and stoichiometric characteristics change in the local zones bordering the bond (the complex type carbide CoxWyCz is formed). As a result, due to these processes, the surface layers’ viscosity of hard alloys and the irradiated products performance increase. Compared to non-irradiated samples of hard alloy, the ultimate strength increases by 15 %, strength and durability – by 30 – 40 %.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80288317","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 : 2023-06-06DOI: 10.17073/0368-0797-2023-2-215-221
N. Nemchinova, A. Tyutrin, A. Zaitseva
The paper presents the results of refining silicon of metallurgical grades based on leaching of impurities with inorganic acids. Silicon samples were studied by metallographic and X-ray fluorescent methods of analysis, as well as X-ray spectral microanalysis. To improve the quality of this alloying element, we carried out experimental work on its hydrometallurgical purification with solutions of various acids (10 % H2SO4 , HCl, HNO3 , 4 % HF) and their mixtures. Values of changes in the Gibbs energy were calculated for reactions of interaction with reagents of the main impurity inclusions recorded in the studied silicon samples (FeSi2 , Fe2Si, FeSi, AlFeSi, AlFeSi2 , Al3FeSi2 , FeSi2Ti, FeAlTiSi, TiSi2 , Ca2Si). The experiments were carried out on silicon samples with a particle size of –200 μm with constant stirring by a magnetic stirrer at a temperature of 60 °С, duration 1 h and L:S = 5:1. Determination of concentration of the impurity elements in the solution after leaching was made by the atomic emission method of analysis. When hydrofluoric acid is used as a solvent, the best results are obtained for purification of iron, aluminum, and titanium (concentration in solution, mg/dm3, respectively: 2380, 831, 145). The maximum concentration of calcium in the solution (147 mg/dm3 ) was achieved by hydrochloric acid treatment of fine silicon. The most effective for transferring impurities into solution is a mixture of sulfuric and hydrofluoric acids at a ratio of 1:1. Using a mixture of H2SO4 and HCl as a solvent (at a ratio of 1:3) made it possible to achieve sufficiently high mass concentrations of impurity elements in the leaching solution. The degree of silicon purification from iron was 33.32 %, aluminum – 54.64 %, calcium – 65.77 %, titanium – 15.64 %.
{"title":"Hydrometallurgical refining of metallurgical silicon","authors":"N. Nemchinova, A. Tyutrin, A. Zaitseva","doi":"10.17073/0368-0797-2023-2-215-221","DOIUrl":"https://doi.org/10.17073/0368-0797-2023-2-215-221","url":null,"abstract":"The paper presents the results of refining silicon of metallurgical grades based on leaching of impurities with inorganic acids. Silicon samples were studied by metallographic and X-ray fluorescent methods of analysis, as well as X-ray spectral microanalysis. To improve the quality of this alloying element, we carried out experimental work on its hydrometallurgical purification with solutions of various acids (10 % H2SO4 , HCl, HNO3 , 4 % HF) and their mixtures. Values of changes in the Gibbs energy were calculated for reactions of interaction with reagents of the main impurity inclusions recorded in the studied silicon samples (FeSi2 , Fe2Si, FeSi, AlFeSi, AlFeSi2 , Al3FeSi2 , FeSi2Ti, FeAlTiSi, TiSi2 , Ca2Si). The experiments were carried out on silicon samples with a particle size of –200 μm with constant stirring by a magnetic stirrer at a temperature of 60 °С, duration 1 h and L:S = 5:1. Determination of concentration of the impurity elements in the solution after leaching was made by the atomic emission method of analysis. When hydrofluoric acid is used as a solvent, the best results are obtained for purification of iron, aluminum, and titanium (concentration in solution, mg/dm3, respectively: 2380, 831, 145). The maximum concentration of calcium in the solution (147 mg/dm3 ) was achieved by hydrochloric acid treatment of fine silicon. The most effective for transferring impurities into solution is a mixture of sulfuric and hydrofluoric acids at a ratio of 1:1. Using a mixture of H2SO4 and HCl as a solvent (at a ratio of 1:3) made it possible to achieve sufficiently high mass concentrations of impurity elements in the leaching solution. The degree of silicon purification from iron was 33.32 %, aluminum – 54.64 %, calcium – 65.77 %, titanium – 15.64 %.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88597947","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 : 2023-03-01DOI: 10.17073/0368-0797-2023-1-35-42
I. Pyshmintsev, A. Gizatullin, N. Devyaterikova, K. Laev, A. Tsvetkov, A. A. Al’khimenko, N. Shaposhnikov, M. Kurakin
To assess resistance to hydrogen embrittlement caused by the presence of hydrogen in the transported product, and, accordingly, suitability of pipes for hydrogen transport, the base metal of large-diameter pipes of X52 strength class manufactured by JSC “ChelPipe” (part of the PJSC “TMK” group of companies) was studied. The work included the study of pure gaseous hydrogen effect under pressure up to 10 MPa on change in mechanical characteristics of the base metal of large-diameter pipes (LDP) during preliminary hydrogen charging for various time periods in a stationary autoclave under pressure, and during simultaneous loading with a slow strain rate (SSRT) under expected operating conditions. Results of the X52 LDP metal study show that there is no significant impact on the effect of gaseous hydrogen under pressure for up to 144 hours on mechanical characteristics of the base metal determined by static uniaxial tension (decrease in ductile characteristics does not exceed 9 %). During SSRT at a rate of not more than 1·10–6 s–1 in pure gaseous hydrogen environment under a pressure of 10 MPa, the change in strength and ductile characteristics does not exceed 13 % in comparison with reference tests in nitrogen environment under the same pressure. The results obtained allow us to consider that the base metal of low-alloy pipe steel with ferrite-perlite microstructure of X52 strength class is sufficiently resistant to hydrogen embrittlement. Final confirmation of the possibility to use LDP made from steel under study will be the results of further qualification tests, including the study of the weld metal and heat-affected zone properties.
{"title":"Preliminary assessment of the possibility to use large-diameter pipes of Х52 steel for transportation of pure gaseous hydrogen under pressure","authors":"I. Pyshmintsev, A. Gizatullin, N. Devyaterikova, K. Laev, A. Tsvetkov, A. A. Al’khimenko, N. Shaposhnikov, M. Kurakin","doi":"10.17073/0368-0797-2023-1-35-42","DOIUrl":"https://doi.org/10.17073/0368-0797-2023-1-35-42","url":null,"abstract":"To assess resistance to hydrogen embrittlement caused by the presence of hydrogen in the transported product, and, accordingly, suitability of pipes for hydrogen transport, the base metal of large-diameter pipes of X52 strength class manufactured by JSC “ChelPipe” (part of the PJSC “TMK” group of companies) was studied. The work included the study of pure gaseous hydrogen effect under pressure up to 10 MPa on change in mechanical characteristics of the base metal of large-diameter pipes (LDP) during preliminary hydrogen charging for various time periods in a stationary autoclave under pressure, and during simultaneous loading with a slow strain rate (SSRT) under expected operating conditions. Results of the X52 LDP metal study show that there is no significant impact on the effect of gaseous hydrogen under pressure for up to 144 hours on mechanical characteristics of the base metal determined by static uniaxial tension (decrease in ductile characteristics does not exceed 9 %). During SSRT at a rate of not more than 1·10–6 s–1 in pure gaseous hydrogen environment under a pressure of 10 MPa, the change in strength and ductile characteristics does not exceed 13 % in comparison with reference tests in nitrogen environment under the same pressure. The results obtained allow us to consider that the base metal of low-alloy pipe steel with ferrite-perlite microstructure of X52 strength class is sufficiently resistant to hydrogen embrittlement. Final confirmation of the possibility to use LDP made from steel under study will be the results of further qualification tests, including the study of the weld metal and heat-affected zone properties.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"238 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74879833","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 : 2023-03-01DOI: 10.17073/0368-0797-2023-1-50-56
V. Gromov, K. Aksenova, Y. Ivanov, R. V. Kuznetsov, V. Kormyshev
The defective substructure of polycrystalline bodies causes substructural hardening and mechanical properties. Perlite, which is the main structural component of rails, undergoes a significant transformation during deformation, which is accompanied by a number of processes. In this paper, the methods of modern physical materials science were used to study and analyze the defective substructure of perlite of lamellar morphology and the properties of rail steel subjected to destruction under deformation conditions by single-axis stretching of flat samples. It was established that the ultimate strength varies from 1247 to 1335 MPa, and the relative deformation to failure – from 0.69 to 0.75. The formation of three zones of the fracture surface was observed: fibrous, radial and shear zones. Their shape and sizes were analyzed. Deformation of rail steel is accompanied by destruction of cementite plates of perlite colonies and repeated release of nanoscale particles of tertiary cementite approximately 8.3 nm in size in the volume of ferrite plates. The main mechanisms of destruction of cementite plates are cutting and dissolution. The dislocation substructure is represented by a chaotic distribution of dislocations and their clusters. The scalar density of dislocations in ferrite increases from 3.2·1010 cm–2 in the initial state to 7.9·1010 cm–2 when it is destroyed. Deformation is accompanied by formation of internal stress fields, manifested in the form of bending extinction contours. The sources of stress fields are the interface of cementite and ferrite plates, as well as grain boundaries. Fragmentation of ferrite and cementite plates was revealed. The average size of cementite fragments is 9.3 nm. In fracture zone of the rail steel sample, rotation of perlite grains was noted, indicating the presence of a rotational mode of deformation. Electron microscopic images of cementite plates show a change in the contrast, which may be associated with the formation of Cottrell’s atmospheres.
{"title":"Transformation of fine structure of lamellar pearlite under deformation of rail steel","authors":"V. Gromov, K. Aksenova, Y. Ivanov, R. V. Kuznetsov, V. Kormyshev","doi":"10.17073/0368-0797-2023-1-50-56","DOIUrl":"https://doi.org/10.17073/0368-0797-2023-1-50-56","url":null,"abstract":"The defective substructure of polycrystalline bodies causes substructural hardening and mechanical properties. Perlite, which is the main structural component of rails, undergoes a significant transformation during deformation, which is accompanied by a number of processes. In this paper, the methods of modern physical materials science were used to study and analyze the defective substructure of perlite of lamellar morphology and the properties of rail steel subjected to destruction under deformation conditions by single-axis stretching of flat samples. It was established that the ultimate strength varies from 1247 to 1335 MPa, and the relative deformation to failure – from 0.69 to 0.75. The formation of three zones of the fracture surface was observed: fibrous, radial and shear zones. Their shape and sizes were analyzed. Deformation of rail steel is accompanied by destruction of cementite plates of perlite colonies and repeated release of nanoscale particles of tertiary cementite approximately 8.3 nm in size in the volume of ferrite plates. The main mechanisms of destruction of cementite plates are cutting and dissolution. The dislocation substructure is represented by a chaotic distribution of dislocations and their clusters. The scalar density of dislocations in ferrite increases from 3.2·1010 cm–2 in the initial state to 7.9·1010 cm–2 when it is destroyed. Deformation is accompanied by formation of internal stress fields, manifested in the form of bending extinction contours. The sources of stress fields are the interface of cementite and ferrite plates, as well as grain boundaries. Fragmentation of ferrite and cementite plates was revealed. The average size of cementite fragments is 9.3 nm. In fracture zone of the rail steel sample, rotation of perlite grains was noted, indicating the presence of a rotational mode of deformation. Electron microscopic images of cementite plates show a change in the contrast, which may be associated with the formation of Cottrell’s atmospheres. ","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86279436","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 : 2023-03-01DOI: 10.17073/0368-0797-2023-1-97-104
I. V. Bakin, A. Shapovalov, A. V. Kalyaskin, M. Kuznetsov
Increasingly rigid requirements in terms of the steel products quality are forcing the technical experts of metallurgical production to look for new solutions to stabilize the steel quality. Much attention is paid to ladle treatment technologies and selection well-minded composition of modifiers, which makes it possible to reduce steel contamination by non-metallic inclusions. To solve this problem, complex modifiers containing both calcium and other alkaline-earth metals (barium and strontium) are used. The paper presents the results of the pilot scale tests of steel ladle treatment by complex modifiers with alkaline-earth metals (Si, Ca, Ba) in steel production with increased requirements to non-metallic inclusions in conditions of electric furnace steelmaking shop of JSC “Ural Steel”. During experimental work it was possible to reduce the maximum contamination score profile rolled steel from pipe steel grades for brittle silicates (GOST 1778) from 4.0 to 1.5 – 2.5, for non-deforming silicates from 4.0 to 3.0 – 3.5. The substitution of SK40 grade silicocalcium for experimental modifiers led to an improvement in the strength properties of rolled products, both in tensile tests and in impact bending tests at low temperatures. The indicated impact was observed in all variants of consumption the experimental master alloys. It is noted that with an increasing in the consumption of master alloys, the positive effect on the steel mechanical properties enhanced. It was established that the replacement of silicocalcium with experimental variants of master alloys made it possible to increase the calcium recovery by an average of 1.6 times when using Si – Ca – Ba, and by an average of 2.4 times when using Si – Ca – Ba – Sr. The use of complex modifiers made it possible to obtain the target value of residual calcium in the sample at significantly lower calcium consumption.
人们对钢铁产品质量的要求越来越严格，迫使冶金生产技术专家寻找新的解决方案来稳定钢铁质量。重视钢包处理技术和合理选择改性剂组合，使减少非金属夹杂物对钢的污染成为可能。为了解决这个问题，使用了含有钙和其他碱土金属(钡和锶)的复合改性剂。本文介绍了在乌拉尔钢铁公司电炉炼钢车间对非金属夹杂物要求提高的情况下，用碱土金属(Si、Ca、Ba)复合改性剂处理钢包的中试结果。在实验工作中，有可能将脆性硅酸盐(GOST 1778)的最大污染分数从管材钢等级从4.0降低到1.5 - 2.5，对于不变形硅酸盐从4.0降低到3.0 - 3.5。用SK40级硅钙代替实验改性剂，在拉伸试验和低温冲击弯曲试验中，轧制产品的强度性能都得到了改善。在实验母合金的所有消耗变量中都观察到所指示的影响。结果表明，随着中间合金用量的增加，中间合金对钢力学性能的积极作用增强。成立的替代硅钙合金与实验变量的主合金成为可能增加1.6倍的平均钙复苏当使用Si - Ca Ba和平均的2.4倍在使用Si - Ca Ba Sr。复合改性剂的使用可以在显著降低钙消耗的情况下获得样品中残余钙的目标值。
{"title":"Impact of barium and strontium on calcium recovery level in ladle treatment of steel by complex modifiers with alkaline-earth metals","authors":"I. V. Bakin, A. Shapovalov, A. V. Kalyaskin, M. Kuznetsov","doi":"10.17073/0368-0797-2023-1-97-104","DOIUrl":"https://doi.org/10.17073/0368-0797-2023-1-97-104","url":null,"abstract":"Increasingly rigid requirements in terms of the steel products quality are forcing the technical experts of metallurgical production to look for new solutions to stabilize the steel quality. Much attention is paid to ladle treatment technologies and selection well-minded composition of modifiers, which makes it possible to reduce steel contamination by non-metallic inclusions. To solve this problem, complex modifiers containing both calcium and other alkaline-earth metals (barium and strontium) are used. The paper presents the results of the pilot scale tests of steel ladle treatment by complex modifiers with alkaline-earth metals (Si, Ca, Ba) in steel production with increased requirements to non-metallic inclusions in conditions of electric furnace steelmaking shop of JSC “Ural Steel”. During experimental work it was possible to reduce the maximum contamination score profile rolled steel from pipe steel grades for brittle silicates (GOST 1778) from 4.0 to 1.5 – 2.5, for non-deforming silicates from 4.0 to 3.0 – 3.5. The substitution of SK40 grade silicocalcium for experimental modifiers led to an improvement in the strength properties of rolled products, both in tensile tests and in impact bending tests at low temperatures. The indicated impact was observed in all variants of consumption the experimental master alloys. It is noted that with an increasing in the consumption of master alloys, the positive effect on the steel mechanical properties enhanced. It was established that the replacement of silicocalcium with experimental variants of master alloys made it possible to increase the calcium recovery by an average of 1.6 times when using Si – Ca – Ba, and by an average of 2.4 times when using Si – Ca – Ba – Sr. The use of complex modifiers made it possible to obtain the target value of residual calcium in the sample at significantly lower calcium consumption.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"27 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79254822","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 : 2023-03-01DOI: 10.17073/0368-0797-2023-1-43-49
Y. Goikhenberg, D. S. Polukhin, D. Zherebtsov, E. G. Bodrov
The authors studied the structure, properties and corrosion resistance in various acids of nickel-phosphorus coatings with dispersed silicon carbides after crystallization annealing under various modes. Temperatures of the beginning of crystallization after heating at speeds of 1, 5, 20 °С/min and the percentage of crystalline phases formed under isothermal conditions (nickel phosphide Ni3P and nickel) were determined. High microhardness of more than 1000 HV is achieved in a composite nickel-phosphorus coating with dispersed particles of silicon carbides during prolonged low-temperature annealing, accompanied by crystallization with formation of already insignificant (10 %) amounts of Ni3P. The revealed dispersed Ni3P located both in the body and along boundaries of the grain, make the main contribution to the increment of microhardness. The yield strength and ultimate strength of coatings increase during crystallization annealing by only 12 – 15 MPa, and the elongation drops to zero, which is due to the formation of brittle Ni3P compounds. Annealing with short soaking at crystallization temperatures leads to the fact that silicon carbides exhibit a barrier effect, reducing the intensity of formation of crystalline Ni3P and corrosion resistance, while long soaking at lower crystallization temperatures forms about 70 % Ni3P, contributing to consistently high hardness and improved corrosion resistance. Corrosion resistance of composite coatings Ni-P + silicon carbides, regardless of the heat treatment modes, is maximum in acetic and orthophosphoric acids at 70 % nickel phosphide and minimum in nitric acid and its mixtures with other acids.
{"title":"Influence of silicon carbides on the structure and properties of composite nickel-phosphorus coating","authors":"Y. Goikhenberg, D. S. Polukhin, D. Zherebtsov, E. G. Bodrov","doi":"10.17073/0368-0797-2023-1-43-49","DOIUrl":"https://doi.org/10.17073/0368-0797-2023-1-43-49","url":null,"abstract":"The authors studied the structure, properties and corrosion resistance in various acids of nickel-phosphorus coatings with dispersed silicon carbides after crystallization annealing under various modes. Temperatures of the beginning of crystallization after heating at speeds of 1, 5, 20 °С/min and the percentage of crystalline phases formed under isothermal conditions (nickel phosphide Ni3P and nickel) were determined. High microhardness of more than 1000 HV is achieved in a composite nickel-phosphorus coating with dispersed particles of silicon carbides during prolonged low-temperature annealing, accompanied by crystallization with formation of already insignificant (10 %) amounts of Ni3P. The revealed dispersed Ni3P located both in the body and along boundaries of the grain, make the main contribution to the increment of microhardness. The yield strength and ultimate strength of coatings increase during crystallization annealing by only 12 – 15 MPa, and the elongation drops to zero, which is due to the formation of brittle Ni3P compounds. Annealing with short soaking at crystallization temperatures leads to the fact that silicon carbides exhibit a barrier effect, reducing the intensity of formation of crystalline Ni3P and corrosion resistance, while long soaking at lower crystallization temperatures forms about 70 % Ni3P, contributing to consistently high hardness and improved corrosion resistance. Corrosion resistance of composite coatings Ni-P + silicon carbides, regardless of the heat treatment modes, is maximum in acetic and orthophosphoric acids at 70 % nickel phosphide and minimum in nitric acid and its mixtures with other acids.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"15 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78913591","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 : 2023-03-01DOI: 10.17073/0368-0797-2023-1-112-118
I. B. Abdukodirov, A. V. Vargin, I. A. Levitskii
Slab heating before hot rolling is necessary for obtaining required metal ductility. The most effective for this purpose are furnaces with walking beams that provide heat supply to all sides of the slab. However, the areas of slabs lower surfaces, contacting with water-cooled beams, are shielded from the radiation of the furnace lower heating zones and take the heat from the beams.To study the inhomogeneity of the slab temperature field and its dependence on the peculiarities of their transport system design, a mathematical model of slab heating in a furnace with walking beams was developed and programmatically implemented, based on numerical solution of a three-dimensional heat conduction problem with piecewise defined boundary conditions on the lower surface. For the open areas of the slab bottom surface, the same boundary conditions were set as on the top surface; and for the areas of contact with the beams, modified boundary conditions were set, taking into account the duration of this contact. For the numerical solution of the system of difference equations, the line-by-line method was applied, which allows us to obtain a system with a three-diagonal matrix of coefficients. The calculations carried out in the approximation of adiabaticity of the contact areas of the slab with the beams during the contact period allowed us to obtain temperature fields for different slab sections. As a result, a significant irregularity of temperature field of the slab lower surface was revealed, affecting the irregularity of temperature field of the entire slab. The developed program for calculating and visualizing the results can be used to study the temperature field of the slab under various heating modes if there is experimental information that allows one to clarify the tuning parameters of the model.
{"title":"Mathematical model of slab heating in a furnace with walking beams","authors":"I. B. Abdukodirov, A. V. Vargin, I. A. Levitskii","doi":"10.17073/0368-0797-2023-1-112-118","DOIUrl":"https://doi.org/10.17073/0368-0797-2023-1-112-118","url":null,"abstract":"Slab heating before hot rolling is necessary for obtaining required metal ductility. The most effective for this purpose are furnaces with walking beams that provide heat supply to all sides of the slab. However, the areas of slabs lower surfaces, contacting with water-cooled beams, are shielded from the radiation of the furnace lower heating zones and take the heat from the beams.To study the inhomogeneity of the slab temperature field and its dependence on the peculiarities of their transport system design, a mathematical model of slab heating in a furnace with walking beams was developed and programmatically implemented, based on numerical solution of a three-dimensional heat conduction problem with piecewise defined boundary conditions on the lower surface. For the open areas of the slab bottom surface, the same boundary conditions were set as on the top surface; and for the areas of contact with the beams, modified boundary conditions were set, taking into account the duration of this contact. For the numerical solution of the system of difference equations, the line-by-line method was applied, which allows us to obtain a system with a three-diagonal matrix of coefficients. The calculations carried out in the approximation of adiabaticity of the contact areas of the slab with the beams during the contact period allowed us to obtain temperature fields for different slab sections. As a result, a significant irregularity of temperature field of the slab lower surface was revealed, affecting the irregularity of temperature field of the entire slab. The developed program for calculating and visualizing the results can be used to study the temperature field of the slab under various heating modes if there is experimental information that allows one to clarify the tuning parameters of the model.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"24 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76483664","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 : 2023-03-01DOI: 10.17073/0368-0797-2023-1-105-111
E. L. Vorozheva, K. Smetanin, V. Kislitsa, D. Kudashov
The authors determined the level of zonal and dendritic segregation in slabs poured by thin-slab technology. The calculated variation coefficients of the content of basic and impurity chemical elements over the slab cross-section do not exceed 10 %, zonal segregation is low. The manganese content measured with the area occupied by the dendritic axes and the interstitial spaces showed the level of dendritic segregation. The manganese concentration varies from 0.6 to 1.1 %, respectively. It was established that the use of dynamic soft compression during solidification makes it possible to grind the primary dendritic structure to form additional centers during the phase transformation of δ-ferrite into austenite. Dimensions of the initial austenitic grains formed taking into account the primary dendritic structure are 3 times smaller in a thin slab than in a slab with a thickness of more than 200 mm. Transformations of the dendritic structure during compression show high workability necessary for the formation of uniform austenitic grains in the fullering before finishing rolling. The study has not confirmed the hypothesis that bainite of coarse morphology in the microstructure of hot-rolled products is formed in segregation areas. The hereditary influence of the primary dendritic structure on the structure formation during rolling was revealed. The manganese concentration varies between the bainite and the “neighboring” structure from 0.68 to 1.01 %, similar to the level of the initial dendritic segregation. Difference in the content of chemical elements affects the processes of recrystallization of austenitic grains during high-temperature rough rolling. Bainite was formed within the framework of chemically “depleted” large austenitic grains that are stable during phase transformation.
{"title":"Metallographic study on the structural features of thin slab and rolled products made from it","authors":"E. L. Vorozheva, K. Smetanin, V. Kislitsa, D. Kudashov","doi":"10.17073/0368-0797-2023-1-105-111","DOIUrl":"https://doi.org/10.17073/0368-0797-2023-1-105-111","url":null,"abstract":"The authors determined the level of zonal and dendritic segregation in slabs poured by thin-slab technology. The calculated variation coefficients of the content of basic and impurity chemical elements over the slab cross-section do not exceed 10 %, zonal segregation is low. The manganese content measured with the area occupied by the dendritic axes and the interstitial spaces showed the level of dendritic segregation. The manganese concentration varies from 0.6 to 1.1 %, respectively. It was established that the use of dynamic soft compression during solidification makes it possible to grind the primary dendritic structure to form additional centers during the phase transformation of δ-ferrite into austenite. Dimensions of the initial austenitic grains formed taking into account the primary dendritic structure are 3 times smaller in a thin slab than in a slab with a thickness of more than 200 mm. Transformations of the dendritic structure during compression show high workability necessary for the formation of uniform austenitic grains in the fullering before finishing rolling. The study has not confirmed the hypothesis that bainite of coarse morphology in the microstructure of hot-rolled products is formed in segregation areas. The hereditary influence of the primary dendritic structure on the structure formation during rolling was revealed. The manganese concentration varies between the bainite and the “neighboring” structure from 0.68 to 1.01 %, similar to the level of the initial dendritic segregation. Difference in the content of chemical elements affects the processes of recrystallization of austenitic grains during high-temperature rough rolling. Bainite was formed within the framework of chemically “depleted” large austenitic grains that are stable during phase transformation.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84350061","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 : 2023-03-01DOI: 10.17073/0368-0797-2023-1-89-96
A. Vusikhis, L. I. Leont’ev, R. Gulyaeva, S. Sergeeva, S. Tyushnyakov
Metallurgical companies in the Urals account for 50 – 60 % of local raw materials. Its deficit is compensated by the use of materials imported from Central Russia, the Kola Peninsula and Kazakhstan. Replacing them with the local raw materials would increase the competitiveness of metal produced in the Urals, so the question of assessing the possibility of replacing imported raw materials with local ones is very relevant. Such raw materials could be siderite ores from the Bakal deposit. They are not in demand by metallurgists because of their low iron content and high magnesium content. With growth of siderites in a charge the magnesium oxide content in slag increases that influences its viscosity and makes it difficult or impossible to smelt using more than 20 % of siderites. The use of boron oxide has been suggested to liquefy the slag. The synthetic slag containing 26.8 % CaO, 38.1 % SiO2 , 11.8 % Al2O3 , 23.6 % MgO, simulating composition of slag from MMK blast-furnace smelting with the addition of 30 % of burnt siderites is short and unstable. The temperature corresponding to the slag viscosity at the blast furnace outlet (0.5 Pa·s) is 1390 °C and the temperature corresponding to the melting point (viscosity 2.5 Pa·s) is 1367 °C. If boric anhydride is added to such a slag, it becomes long and stable. In the melts, when the proportion of B2O3 is increased from 0 to 12 %, the temperature at which the slag viscosity is 0.5 Pa·s and 2.5 Pa·s decreases to 1260 °C, and 1100 °C, respectively. This makes it possible to significantly increase the siderite content in blast furnace charge.
{"title":"Effect of B2O3 on viscosity of high-magnesia blast furnace slag","authors":"A. Vusikhis, L. I. Leont’ev, R. Gulyaeva, S. Sergeeva, S. Tyushnyakov","doi":"10.17073/0368-0797-2023-1-89-96","DOIUrl":"https://doi.org/10.17073/0368-0797-2023-1-89-96","url":null,"abstract":"Metallurgical companies in the Urals account for 50 – 60 % of local raw materials. Its deficit is compensated by the use of materials imported from Central Russia, the Kola Peninsula and Kazakhstan. Replacing them with the local raw materials would increase the competitiveness of metal produced in the Urals, so the question of assessing the possibility of replacing imported raw materials with local ones is very relevant. Such raw materials could be siderite ores from the Bakal deposit. They are not in demand by metallurgists because of their low iron content and high magnesium content. With growth of siderites in a charge the magnesium oxide content in slag increases that influences its viscosity and makes it difficult or impossible to smelt using more than 20 % of siderites. The use of boron oxide has been suggested to liquefy the slag. The synthetic slag containing 26.8 % CaO, 38.1 % SiO2 , 11.8 % Al2O3 , 23.6 % MgO, simulating composition of slag from MMK blast-furnace smelting with the addition of 30 % of burnt siderites is short and unstable. The temperature corresponding to the slag viscosity at the blast furnace outlet (0.5 Pa·s) is 1390 °C and the temperature corresponding to the melting point (viscosity 2.5 Pa·s) is 1367 °C. If boric anhydride is added to such a slag, it becomes long and stable. In the melts, when the proportion of B2O3 is increased from 0 to 12 %, the temperature at which the slag viscosity is 0.5 Pa·s and 2.5 Pa·s decreases to 1260 °C, and 1100 °C, respectively. This makes it possible to significantly increase the siderite content in blast furnace charge.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"7 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90821832","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 : 2023-03-01DOI: 10.17073/0368-0797-2023-1-127-132
F. Bahfie, A. Manaf, W. Astuti, F. Nurjaman, S. Suharto, U. Herlina, W. A. Adi, Maykel Manawan
The selective reduction process generates products in the form of concentrates and tailing/by-products. There is high percentage of iron and other elements in the tailings that are not extracted in selective reduction process. Properties of by-products of selective reduction were investigated using X-ray diffraction (XRD), inductively coupled plasma optical emission spectroscopy (ICP–OES), ultraviolet-visible (UV–VIS), and scanning electron microscopy energy dispersion spectroscopy (SEM–EDS). Based on the results of this study, the properties of iron-sulfur, iron-magnesium-aluminium, and silica phases in the tailings can be interpreted experimentally. For future research, it can be the reference for such processes as acid and base leaching. Pure iron extracted from tailings can be used for metal fuel in the future. The tailings composition data will help future researchers to find optimal processes for the tailings.
{"title":"Composition of tailings after selective reduction of laterite","authors":"F. Bahfie, A. Manaf, W. Astuti, F. Nurjaman, S. Suharto, U. Herlina, W. A. Adi, Maykel Manawan","doi":"10.17073/0368-0797-2023-1-127-132","DOIUrl":"https://doi.org/10.17073/0368-0797-2023-1-127-132","url":null,"abstract":"The selective reduction process generates products in the form of concentrates and tailing/by-products. There is high percentage of iron and other elements in the tailings that are not extracted in selective reduction process. Properties of by-products of selective reduction were investigated using X-ray diffraction (XRD), inductively coupled plasma optical emission spectroscopy (ICP–OES), ultraviolet-visible (UV–VIS), and scanning electron microscopy energy dispersion spectroscopy (SEM–EDS). Based on the results of this study, the properties of iron-sulfur, iron-magnesium-aluminium, and silica phases in the tailings can be interpreted experimentally. For future research, it can be the reference for such processes as acid and base leaching. Pure iron extracted from tailings can be used for metal fuel in the future. The tailings composition data will help future researchers to find optimal processes for the tailings.","PeriodicalId":14630,"journal":{"name":"Izvestiya. Ferrous Metallurgy","volume":"154 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79479868","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：