O. Shcheretskyi, A. Verkhovliuk, D. S. Kanibolotsky
Literature review on magnesium, zinc and aluminum-based sacrificial anode alloys chemical and phase compositions have been performed. Technological phase diagrams of aluminum-based sacrificial anode alloys with different content of harmful additives, such as iron, silicon and copper, have been calculated and constructed. It is determined that the harmful effect of iron is in faster dissolution of the anode due to large inclusions of iron intermetallic. This iron negative effect can be eliminated in several ways: a) maximization of the melt cooling rate, which will lead to significant grinding of the intermetallics and thus reduce their negative impact; b) high-temperature homogenization of the alloy with subsequent rapid cooling, which will reduce the size of the iron intermetallic inclusions; c) doping the alloy with additional manganese to bind iron in ternary compound, which has a different shape and size than the binary intermetallic and has less negative effect on the sacrificial anode alloy. To eliminate the negative effects of silicon, the alloy has to be additionally doped with magnesium in an amount that will ensure the silicon complete binding. In this case, the phase composition of the alloy will correspond the AP4 alloy (% wt.%: (4.0-6.0) Zn), (0.5-1.0) Mg, (0.05-1.00) Sn , ˂ 0.10 Si, ˂ 0.10 Fe, ˂ 0.01 Cu). Long-term heat treatment of the alloy at a temperature of 120 ° C is proposed to reduce the copper harmful effect on the aluminum-based sacrificial anode alloys. Almost all copper can pass from the solid aluminum solution into the Al2Cu compound during this processing. Keywords: sacrificial anode alloys, aluminum alloys, impurities, technological phase diagrams.
{"title":"Thermodynamic analysis of aluminium-based sacrificial anode alloys phase composition","authors":"O. Shcheretskyi, A. Verkhovliuk, D. S. Kanibolotsky","doi":"10.15407/mom2022.01.003","DOIUrl":"https://doi.org/10.15407/mom2022.01.003","url":null,"abstract":"Literature review on magnesium, zinc and aluminum-based sacrificial anode alloys chemical and phase compositions have been performed. Technological phase diagrams of aluminum-based sacrificial anode alloys with different content of harmful additives, such as iron, silicon and copper, have been calculated and constructed. It is determined that the harmful effect of iron is in faster dissolution of the anode due to large inclusions of iron intermetallic. This iron negative effect can be eliminated in several ways: a) maximization of the melt cooling rate, which will lead to significant grinding of the intermetallics and thus reduce their negative impact; b) high-temperature homogenization of the alloy with subsequent rapid cooling, which will reduce the size of the iron intermetallic inclusions; c) doping the alloy with additional manganese to bind iron in ternary compound, which has a different shape and size than the binary intermetallic and has less negative effect on the sacrificial anode alloy. To eliminate the negative effects of silicon, the alloy has to be additionally doped with magnesium in an amount that will ensure the silicon complete binding. In this case, the phase composition of the alloy will correspond the AP4 alloy (% wt.%: (4.0-6.0) Zn), (0.5-1.0) Mg, (0.05-1.00) Sn , ˂ 0.10 Si, ˂ 0.10 Fe, ˂ 0.01 Cu). Long-term heat treatment of the alloy at a temperature of 120 ° C is proposed to reduce the copper harmful effect on the aluminum-based sacrificial anode alloys. Almost all copper can pass from the solid aluminum solution into the Al2Cu compound during this processing. Keywords: sacrificial anode alloys, aluminum alloys, impurities, technological phase diagrams.","PeriodicalId":33600,"journal":{"name":"Metaloznavstvo ta obrobka metaliv","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42096755","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}
The effect of melt overheating over the equilibrium liquidus to temperatures of 1570 ºС, 1620 ºС and 1670 ºС and heat removal conditions (normal and rapid cooling) on the formation of a gradient structure and fracture characteristics over the cross section of castings of 25L and 30HGSL steels was investigated. The differentiated phase-structural state of rectangular castings (60x60x100 mm) was provided by the predominant one-sided heat removal in foundry molds with different heat removal capacity and average cooling rate 2 – 5 ºС/s and 300 – 350 ºС/s. Regular changes in the length of the main macrostructural zones in castings are established depending on the crystallization conditions, in particular, an increase in the zone of near-surface small crystals and the transcrystallization zone during rapid cooling of the melt. It is shown that depending on the temperature conditions of melt preparation and cooling during crystallization, the grain size in the cross section of castings varies by 4-5 numbers (steel 25L) and by 6-8 numbers (steel 30HGSL). The rapid cooling of the melt causes a significant increase in the impact strength of the cross section of the castings in the range of 50-35 J/cm2 (steel 25L) and 40-20 J/cm2 (steel 30HGSL), even under conditions of significant overheating of the melt. Under normal cooling conditions, there is a significant decrease in the values of impact strength in the cross section of the castings from 30 to 15 J/cm2. According to the results of determining the toughness in castings with differentiated structure depending on the crystallization conditions and test temperature (+20 ºС… -60 ºС) the regression equation for changing its values in the range of viscous-brittle transition temperatures and brittleness temperature (Tbrtl50) of steels in the volume of castings. The obtained results create preconditions for the development of technological principles of engineering of cast steel products to ensure the specified properties in accordance with the requirements of their operation. Keywords: steel, crystallization, gradient structure, toughness.
{"title":"Gradient structure and fracture characteristics of steel castings","authors":"S. Kondratyuk, Z. Parkhomchuk, V. I. Veis","doi":"10.15407/mom2022.01.015","DOIUrl":"https://doi.org/10.15407/mom2022.01.015","url":null,"abstract":"The effect of melt overheating over the equilibrium liquidus to temperatures of 1570 ºС, 1620 ºС and 1670 ºС and heat removal conditions (normal and rapid cooling) on the formation of a gradient structure and fracture characteristics over the cross section of castings of 25L and 30HGSL steels was investigated. The differentiated phase-structural state of rectangular castings (60x60x100 mm) was provided by the predominant one-sided heat removal in foundry molds with different heat removal capacity and average cooling rate 2 – 5 ºС/s and 300 – 350 ºС/s. Regular changes in the length of the main macrostructural zones in castings are established depending on the crystallization conditions, in particular, an increase in the zone of near-surface small crystals and the transcrystallization zone during rapid cooling of the melt. It is shown that depending on the temperature conditions of melt preparation and cooling during crystallization, the grain size in the cross section of castings varies by 4-5 numbers (steel 25L) and by 6-8 numbers (steel 30HGSL). The rapid cooling of the melt causes a significant increase in the impact strength of the cross section of the castings in the range of 50-35 J/cm2 (steel 25L) and 40-20 J/cm2 (steel 30HGSL), even under conditions of significant overheating of the melt. Under normal cooling conditions, there is a significant decrease in the values of impact strength in the cross section of the castings from 30 to 15 J/cm2. According to the results of determining the toughness in castings with differentiated structure depending on the crystallization conditions and test temperature (+20 ºС… -60 ºС) the regression equation for changing its values in the range of viscous-brittle transition temperatures and brittleness temperature (Tbrtl50) of steels in the volume of castings. The obtained results create preconditions for the development of technological principles of engineering of cast steel products to ensure the specified properties in accordance with the requirements of their operation. Keywords: steel, crystallization, gradient structure, toughness.","PeriodicalId":33600,"journal":{"name":"Metaloznavstvo ta obrobka metaliv","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47890874","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}
S. Kondratyuk, V. I. Veis, Z. Parkhomchuk, V.A. Loktyonov-Remyzovskii
The effect of overheating of the melt over the equilibrium liquidus in the temperature range 1570 °C – 1670 °C and the rate of its cooling during crystallization and structure formation of castings on the formation of the length and morphology of the main macrostructural zones, grain dispersion, characteristics of the fine crystal structure, hardness and intensity of abrasive wear over the section of 25L steel castings with a differentiated cast structure was investigated. Regular changes of these indicators depending on thermokinetic conditions of crystallization are established. The determining influence of the melt cooling rate on the morphology and dispersion of the cast structure due to different degrees of melt supercooling during crystallization of different structural zones of castings is shown. As the distance from the rapidly cooling surface of the castings and taking into account the increase in the temperature of the melt overheat from 1570 ºC to 1670 ºC, the grain size varies from 5… 7 numbers to 1… 2 numbers, respectively. In the case of normal heat removal rate during crystallization, the grain size in the castings varies from 4… 2 to -1… -2 numbers. The determined characteristics of wear resistance of steel in different structural zones correlate with changes in the characteristics of the cast structure and the cross-sectional strength of castings. The research results open the prospect of developing new foundry technologies for the production of cast products with differential properties for special operating conditions. Keywords: gradient structure, structural zones, melt, wear.
{"title":"Structure and wear of gradient steel castings","authors":"S. Kondratyuk, V. I. Veis, Z. Parkhomchuk, V.A. Loktyonov-Remyzovskii","doi":"10.15407/mom2021.04.016","DOIUrl":"https://doi.org/10.15407/mom2021.04.016","url":null,"abstract":"The effect of overheating of the melt over the equilibrium liquidus in the temperature range 1570 °C – 1670 °C and the rate of its cooling during crystallization and structure formation of castings on the formation of the length and morphology of the main macrostructural zones, grain dispersion, characteristics of the fine crystal structure, hardness and intensity of abrasive wear over the section of 25L steel castings with a differentiated cast structure was investigated. Regular changes of these indicators depending on thermokinetic conditions of crystallization are established. The determining influence of the melt cooling rate on the morphology and dispersion of the cast structure due to different degrees of melt supercooling during crystallization of different structural zones of castings is shown. As the distance from the rapidly cooling surface of the castings and taking into account the increase in the temperature of the melt overheat from 1570 ºC to 1670 ºC, the grain size varies from 5… 7 numbers to 1… 2 numbers, respectively. In the case of normal heat removal rate during crystallization, the grain size in the castings varies from 4… 2 to -1… -2 numbers. The determined characteristics of wear resistance of steel in different structural zones correlate with changes in the characteristics of the cast structure and the cross-sectional strength of castings. The research results open the prospect of developing new foundry technologies for the production of cast products with differential properties for special operating conditions. Keywords: gradient structure, structural zones, melt, wear.","PeriodicalId":33600,"journal":{"name":"Metaloznavstvo ta obrobka metaliv","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46301356","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}
Results of comprehensive studies of samples of prematurely destroyed 57×4 mm steam superheaer tubes of STBA 22 steel used in a boiler unit of Singburi Sugar Co, Ltd factory (Thailand) are presented. The tubes were manufactured at Interpipe Niko Tube Ltd. (Ukraine) according to JIS G 3462 Standard (Japan). They were destroyed in a short (~240 hrs) term of operation. The cause of premature destruction of tubes of the above steel grade and size assortment in the boiler unit has been established. Based on present-day investigation methods (metallography, X-ray diffraction, etc.), it was found that the tubes were operated with violation of fuel combustion conditions and heat-carrying agent circulation. Characteristic features of operation of damaged tubes include high thermal stresses from the side of the fire-chamber and limitation (or absence) of circulation of the heat-carrying agent (blockage in bends, drum heads, etc.). During operation, the tubes were also exposed to significant thermal vibration stresses (unstable combustion conditions). Prolonged overheating occurred at temperatures above 1000 °C because of violation of circulation of heat-carrying agent and unstable combustion mode. High thermal stresses at almost complete absence of a heat-carrying agent, uneven distribution of growing heat flows caused by violation of the combustion mode in the fire-chamber contributed to accelerated degradation of structure and thermal destruction of the tube metal. In a short term of operation (~240 hours), there was a significant change in the tube size (accelerated high-temperature creep) and complete recrystallization of metal structure throughout the entire wall thickness of the damaged tubes. It has been established that the accelerated degradation of metal microstructure in the destroyed tubes was associated with both overheating of the tube wall and the as-delivered metal structure non-recommended for operation at high temperatures and pressures. It was shown that it is necessary to adjust the heat treatment conditions for these tubes at Interpipe Niko Tube Ltd. The study results have made it possible to develop recommendations for eliminating violations of operating conditions and establishing control of actual heat flows in the most thermally loaded sections of the Singburi Sugar Co. Ltd factory’s steam boiler superheater. Taking into account peculiarities of the boiler equipment and its operating conditions, it was also recommended to use a more heat-resistant and refractory steel instead of the currently used material for manufacture of the steam superheater tubes. Keywords: boiler tube, steam superheater, damage, thermal destruction, structure degradation, combustion conditions, heat carrier circulation, overheating.
本文介绍了泰国Singburi糖业有限公司锅炉机组中stba22钢的57×4 mm蒸汽过热管过早损坏样品的综合研究结果。这些管子由Interpipe Niko Tube Ltd.(乌克兰)根据JIS G 3462标准(日本)制造。它们在短时间内(约240小时)被摧毁。找出了锅炉机组中上述钢种和尺寸组合管过早损坏的原因。根据现有的研究方法(金相、x射线衍射等)，发现这些管道的运行违反了燃料燃烧条件和载热剂循环。损坏管道的运行特征包括来自火室侧面的高热应力和热传导剂循环的限制(或缺乏)(弯道，鼓头等堵塞)。在运行过程中，这些管道还暴露在显著的热振动应力(不稳定的燃烧条件)下。在温度超过1000℃时，由于载热剂的循环被破坏，燃烧方式不稳定，导致长时间过热。在几乎完全没有载热剂的情况下产生的高热应力，以及在火室中违反燃烧模式导致的不断增长的热流分布不均匀，都有助于加速结构的退化和管金属的热破坏。在短时间内(~240小时)，管的尺寸发生了明显的变化(高温蠕变加速)，损坏管的整个壁厚的金属结构完全再结晶。研究表明，破坏后的钢管中金属微观结构的加速退化与管壁过热和交付时的金属结构不适合高温高压运行有关。结果表明，有必要对这些钢管的热处理条件进行调整。研究结果使我们有可能提出建议，以消除违反操作条件的情况，并在Singburi糖业有限公司工厂蒸汽锅炉过热器的最热负荷部分建立实际热流控制。考虑到锅炉设备的特点及其运行条件，建议使用耐热性和耐火性能更好的钢代替目前使用的蒸汽过热器管制造材料。关键词:锅炉管，蒸汽过热器，损坏，热破坏，结构退化，燃烧条件，热载体循环，过热。
{"title":"Studying the causes of destruction of steam superheater tubes in boiler equipment","authors":"L. Opryshko, T. Golovnyak","doi":"10.15407/mom2021.04.052","DOIUrl":"https://doi.org/10.15407/mom2021.04.052","url":null,"abstract":"Results of comprehensive studies of samples of prematurely destroyed 57×4 mm steam superheaer tubes of STBA 22 steel used in a boiler unit of Singburi Sugar Co, Ltd factory (Thailand) are presented. The tubes were manufactured at Interpipe Niko Tube Ltd. (Ukraine) according to JIS G 3462 Standard (Japan). They were destroyed in a short (~240 hrs) term of operation. The cause of premature destruction of tubes of the above steel grade and size assortment in the boiler unit has been established. Based on present-day investigation methods (metallography, X-ray diffraction, etc.), it was found that the tubes were operated with violation of fuel combustion conditions and heat-carrying agent circulation. Characteristic features of operation of damaged tubes include high thermal stresses from the side of the fire-chamber and limitation (or absence) of circulation of the heat-carrying agent (blockage in bends, drum heads, etc.). During operation, the tubes were also exposed to significant thermal vibration stresses (unstable combustion conditions). Prolonged overheating occurred at temperatures above 1000 °C because of violation of circulation of heat-carrying agent and unstable combustion mode. High thermal stresses at almost complete absence of a heat-carrying agent, uneven distribution of growing heat flows caused by violation of the combustion mode in the fire-chamber contributed to accelerated degradation of structure and thermal destruction of the tube metal. In a short term of operation (~240 hours), there was a significant change in the tube size (accelerated high-temperature creep) and complete recrystallization of metal structure throughout the entire wall thickness of the damaged tubes. It has been established that the accelerated degradation of metal microstructure in the destroyed tubes was associated with both overheating of the tube wall and the as-delivered metal structure non-recommended for operation at high temperatures and pressures. It was shown that it is necessary to adjust the heat treatment conditions for these tubes at Interpipe Niko Tube Ltd. The study results have made it possible to develop recommendations for eliminating violations of operating conditions and establishing control of actual heat flows in the most thermally loaded sections of the Singburi Sugar Co. Ltd factory’s steam boiler superheater. Taking into account peculiarities of the boiler equipment and its operating conditions, it was also recommended to use a more heat-resistant and refractory steel instead of the currently used material for manufacture of the steam superheater tubes. Keywords: boiler tube, steam superheater, damage, thermal destruction, structure degradation, combustion conditions, heat carrier circulation, overheating.","PeriodicalId":33600,"journal":{"name":"Metaloznavstvo ta obrobka metaliv","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41947571","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}
K. Gogaev, Y. Podrezov, S. Voloshchenko, M. Askerov, M. Minakov
The effect of manganese content on the phase composition and mechanical properties was studied on ADI materials that are isothermally quenchеd at different temperatures. ADI samples with Mn content of 0.78% and 0.24% were analyzed. The final structure of the cast iron was created by austenitizing heating at 900 ° C for 30 minutes. and subsequent isothermal quenching in liquid tin at temperatures of 310, 330, 350, 380 ° C for samples with high manganese content and at 350, 370 ° C for samples with low content. It is shown that increasing the manganese content increases the amount of residual austenite under the same quenching conditions. This enhances the positive role of the TRIP effect on the hardening processes. In particular, ADI with a high content of Mn show a higher rate of strengthening at the initial region of loading diagram, higher hardness and increased damping capacity. Instead, due to the embrittlement action of manganese, such materials have lower mechanical characteristics, which determined fracture moment. It was found that for the same quenching conditions, deformation to fracture and toughness are reduced by half on samples with higher manganese content. The negative effect of manganese on the fatigue is less significant, because the embrittlement action is compensated by phase transformations in the crack head, which inhibits its spread under cyclic loading. Due to the fact that manganese enhances the positive role of the TRIP effect but decrease fracture résistance, it is proposed to use ADI materials with high Mn content in products that operate in conditions of wear but are not subject to extreme stress. Keywords: ADI materials, manganese alloying, isothermal hardening, TRIP effect, retained austenite, strengthening, hardness. damping capacity.
{"title":"Sensitivity to Mn content mechanical properties of phase composition of ADI","authors":"K. Gogaev, Y. Podrezov, S. Voloshchenko, M. Askerov, M. Minakov","doi":"10.15407/mom2021.04.003","DOIUrl":"https://doi.org/10.15407/mom2021.04.003","url":null,"abstract":"The effect of manganese content on the phase composition and mechanical properties was studied on ADI materials that are isothermally quenchеd at different temperatures. ADI samples with Mn content of 0.78% and 0.24% were analyzed. The final structure of the cast iron was created by austenitizing heating at 900 ° C for 30 minutes. and subsequent isothermal quenching in liquid tin at temperatures of 310, 330, 350, 380 ° C for samples with high manganese content and at 350, 370 ° C for samples with low content. It is shown that increasing the manganese content increases the amount of residual austenite under the same quenching conditions. This enhances the positive role of the TRIP effect on the hardening processes. In particular, ADI with a high content of Mn show a higher rate of strengthening at the initial region of loading diagram, higher hardness and increased damping capacity. Instead, due to the embrittlement action of manganese, such materials have lower mechanical characteristics, which determined fracture moment. It was found that for the same quenching conditions, deformation to fracture and toughness are reduced by half on samples with higher manganese content. The negative effect of manganese on the fatigue is less significant, because the embrittlement action is compensated by phase transformations in the crack head, which inhibits its spread under cyclic loading. Due to the fact that manganese enhances the positive role of the TRIP effect but decrease fracture résistance, it is proposed to use ADI materials with high Mn content in products that operate in conditions of wear but are not subject to extreme stress. Keywords: ADI materials, manganese alloying, isothermal hardening, TRIP effect, retained austenite, strengthening, hardness. damping capacity.","PeriodicalId":33600,"journal":{"name":"Metaloznavstvo ta obrobka metaliv","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46811090","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}
Modern technological schemes of steel production do not allow to achieve low (< 0.01 % S) and ultra-low (<0.005 % S) sulfur content on the production of in the metal directly. That is why out-of-furnace steel treatment is often used to remove sulfur. Desulfurization process of steel depends on the chemical composition of the slag, the time of its formation in the ladle, metal oxidation, conditions of mixing of steel in a ladle, additional technological operations and ladle metal processing. Methods are widely used for desulfurization of steel treatment of steel with solid slag-forming mixtures, synthetic slag, lime-aluminous slag, silico-calcium and other powdered materials. Modern approaches to the process of steel desulfurization in conditions steel production are analyzed in the Study. In particular, the Ukrainian (on the example of PJSC ‘Azovstal Iron & Steel Works’ and PJSC ‘Dneprovsky Integrated Iron & Steel Works named after Dzershinsky’) and foreign (on the example of PJSC ‘Severstal’ and PJSC ‘Magnitogorsk Iron & Steel Works’) experience of desulfurization under oxygen converter production. The use of technological complexes ‘Installation of pig iron desulfurization steel making unit’ and ‘Cast iron desulfurization installation steel making unit is ‘oven-bucket’ installation’ provides a deeper desulfurization of steel, the possibility of optimizing the cost of steel production, expands range of scarce products and eliminates a number of restrictive conditions that complicate current production. The analysis of steel C80D desulfurization process is given in the conditions of JSC ‘Moldova Steel Works’, in which partial sulfur removal occurs in an arc steel making furnace, and the ultra-low content is achieved by creating a highly basic refining slag in the process out-of-furnace processing of steel. The study of the kinetics of the desulfurization process of 20GL steel in the conditions of JSC ‘Tashkent Mechanical Plant’ with the use of solid slag-forming mixtures and modification of steel with rare-earth metals is analyzed. The issue of desulfurization of electric steel in the conditions of OJSC ‘Byelorussian Steel Works’ with injection of powdered materials through the installation ‘Velko’ during out-of-furnace processing of steel is considered. Keywords: steel desulfurization, desulfurizer reagent, degree of desulfurization, cast iron desulfurization installation, out-of-furnace processing of steel, ‘‘oven-bucket’’ installation.
{"title":"Modern view on steel desulfurization","authors":"O. Vodennikova, P.V. Holovkov","doi":"10.15407/mom2021.04.033","DOIUrl":"https://doi.org/10.15407/mom2021.04.033","url":null,"abstract":"Modern technological schemes of steel production do not allow to achieve low (< 0.01 % S) and ultra-low (<0.005 % S) sulfur content on the production of in the metal directly. That is why out-of-furnace steel treatment is often used to remove sulfur. Desulfurization process of steel depends on the chemical composition of the slag, the time of its formation in the ladle, metal oxidation, conditions of mixing of steel in a ladle, additional technological operations and ladle metal processing. Methods are widely used for desulfurization of steel treatment of steel with solid slag-forming mixtures, synthetic slag, lime-aluminous slag, silico-calcium and other powdered materials. Modern approaches to the process of steel desulfurization in conditions steel production are analyzed in the Study. In particular, the Ukrainian (on the example of PJSC ‘Azovstal Iron & Steel Works’ and PJSC ‘Dneprovsky Integrated Iron & Steel Works named after Dzershinsky’) and foreign (on the example of PJSC ‘Severstal’ and PJSC ‘Magnitogorsk Iron & Steel Works’) experience of desulfurization under oxygen converter production. The use of technological complexes ‘Installation of pig iron desulfurization steel making unit’ and ‘Cast iron desulfurization installation steel making unit is ‘oven-bucket’ installation’ provides a deeper desulfurization of steel, the possibility of optimizing the cost of steel production, expands range of scarce products and eliminates a number of restrictive conditions that complicate current production. The analysis of steel C80D desulfurization process is given in the conditions of JSC ‘Moldova Steel Works’, in which partial sulfur removal occurs in an arc steel making furnace, and the ultra-low content is achieved by creating a highly basic refining slag in the process out-of-furnace processing of steel. The study of the kinetics of the desulfurization process of 20GL steel in the conditions of JSC ‘Tashkent Mechanical Plant’ with the use of solid slag-forming mixtures and modification of steel with rare-earth metals is analyzed. The issue of desulfurization of electric steel in the conditions of OJSC ‘Byelorussian Steel Works’ with injection of powdered materials through the installation ‘Velko’ during out-of-furnace processing of steel is considered. Keywords: steel desulfurization, desulfurizer reagent, degree of desulfurization, cast iron desulfurization installation, out-of-furnace processing of steel, ‘‘oven-bucket’’ installation.","PeriodicalId":33600,"journal":{"name":"Metaloznavstvo ta obrobka metaliv","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42849051","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}
A. Narivsky, O. Smirnov, V. Panarin, Yu.P. Skorobagatko, M. Goryuk, V. O. Tverdokhvalov, V.M. Lomakin
Growth of production of cast products and the desire of enterprises to reduce the cost of manufacturing metal products led to a significant increase in requirements for the structure and properties of aluminum alloys. Increasing of physical and mechanical properties of alloys is most effectively at the stages of their preparation in liquid state. At that, it is possible to affect effectively on the quality of cast metal by external actions on alloys, deep refining from gases and harmful impurities, active modifying of alloy, reducing or eliminating the negative impact of heredity of charge materials. The main disadvantage of the processes of structure refinement of alloys by using modifiers is instability of their results, which depends on various reasons. One of the most important reasons is providing conditions for the formation and preservation of active modifier particles in the melt volume. They are assimilating by liquid alloy and acting on crystal nucleus at crystallization. It is known that only ~10% particles are active of the total number of particles added with the ligature into the melt. Other particles dissolve in the melt, take away by the crystallization front, or push back on to intergranular boundaries. The considered methods of electromagnetic, MHD and plasma actions on liquid metal allow to refine and modify alloys without use of special reagents. The paper presents studying of the structure and properties of supereutectic silumin A390 after treatment in casting magnetodynamic installation (MDI) by submerged into melt the plasma argon jet and alternating electromagnetic field & magnetohydrodynamic (MHD) effects, including simultaneous combination. There are developed the scientific and technological bases of MHD-plasma processing of liquid hypereutectic silumin A390 and original equipment for their realization. It provides dispersed structure of solidified alloy. Thus, there is a significant decreasing of sizes both particles of primary silicon and dendrites of α-solid solution of aluminium. Also, strength characteristics of alloys increased to 10%, and elongation rises up in 1.5-2 times. Keywords: plasma jet, magnetodynamic installation (MDI), aluminum alloy, mechanical properties.
{"title":"Influence of MHD - plasma melt processing on the structure and properties of cast aluminum alloy A390","authors":"A. Narivsky, O. Smirnov, V. Panarin, Yu.P. Skorobagatko, M. Goryuk, V. O. Tverdokhvalov, V.M. Lomakin","doi":"10.15407/mom2021.04.024","DOIUrl":"https://doi.org/10.15407/mom2021.04.024","url":null,"abstract":"Growth of production of cast products and the desire of enterprises to reduce the cost of manufacturing metal products led to a significant increase in requirements for the structure and properties of aluminum alloys. Increasing of physical and mechanical properties of alloys is most effectively at the stages of their preparation in liquid state. At that, it is possible to affect effectively on the quality of cast metal by external actions on alloys, deep refining from gases and harmful impurities, active modifying of alloy, reducing or eliminating the negative impact of heredity of charge materials. The main disadvantage of the processes of structure refinement of alloys by using modifiers is instability of their results, which depends on various reasons. One of the most important reasons is providing conditions for the formation and preservation of active modifier particles in the melt volume. They are assimilating by liquid alloy and acting on crystal nucleus at crystallization. It is known that only ~10% particles are active of the total number of particles added with the ligature into the melt. Other particles dissolve in the melt, take away by the crystallization front, or push back on to intergranular boundaries. The considered methods of electromagnetic, MHD and plasma actions on liquid metal allow to refine and modify alloys without use of special reagents. The paper presents studying of the structure and properties of supereutectic silumin A390 after treatment in casting magnetodynamic installation (MDI) by submerged into melt the plasma argon jet and alternating electromagnetic field & magnetohydrodynamic (MHD) effects, including simultaneous combination. There are developed the scientific and technological bases of MHD-plasma processing of liquid hypereutectic silumin A390 and original equipment for their realization. It provides dispersed structure of solidified alloy. Thus, there is a significant decreasing of sizes both particles of primary silicon and dendrites of α-solid solution of aluminium. Also, strength characteristics of alloys increased to 10%, and elongation rises up in 1.5-2 times. Keywords: plasma jet, magnetodynamic installation (MDI), aluminum alloy, mechanical properties.","PeriodicalId":33600,"journal":{"name":"Metaloznavstvo ta obrobka metaliv","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46232511","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}
The aim of this work is to obtain predictive regression models, with which it is possible to adequately calculate the mechanical properties of heat-resistant nickel alloys, without prior experiments. Industrial alloys of directional crystallization of domestic and foreign production were selected for research. The values were processed by the method of least squares to obtain correlations with the receipt of mathematical equations of regression models that optimally describe these dependencies. As a result of processing of experimental data, the ratio of alloying elements which can be used for an estimation of mechanical properties taking into account complex influence of the main components of an alloy is offered for the first time. Since the dimensional mismatch of the lattice parameters is associated with the degree of concentration of solid-soluble hardening of γ- and γ'-phases, the efficiency of dispersion hardening of the alloy, creep rate and other properties, the obtained ratio allows to link these properties with multicomponent systems. Regression models are presented, with the help of which it is possible to calculate dimensional mismatch, strength, heat resistance, number of phases and density of alloys with high accuracy. The regularities of the composition influence on the properties of heat-resistant nickel alloys of directional crystallization are established. It is shown that for multicomponent nickel systems it is possible to predict with high probability misfit, which significantly affects the strength characteristics of alloys of this class. The decrease in the value of misfit is accompanied by an increase in the solubility of the elements in the -solid solution at a value of the ratio of alloying elements of 1.5 - 1.6. However, an increase in the ratio of alloying elements greater than 2 is accompanied by an increase in misfit, because the -solid solution has reached a maximum of dissolution. The perspective and effective direction in the decision of a problem of forecasting of the basic characteristics influencing a complex of service properties of alloys both at development of new heat-resistant nickel alloys, and at perfection of structures of known industrial marks of this class is shown. Keywords: nickel-based superalloys, dimensional mismatch (γ / γ'- mismatch), strength, heat resistance.
{"title":"Predicting the properties of nickel-based superalloys directional crystallization","authors":"O. Glotka, V. Olshanetskii","doi":"10.15407/mom2021.03.015","DOIUrl":"https://doi.org/10.15407/mom2021.03.015","url":null,"abstract":"The aim of this work is to obtain predictive regression models, with which it is possible to adequately calculate the mechanical properties of heat-resistant nickel alloys, without prior experiments. Industrial alloys of directional crystallization of domestic and foreign production were selected for research. The values were processed by the method of least squares to obtain correlations with the receipt of mathematical equations of regression models that optimally describe these dependencies. As a result of processing of experimental data, the ratio of alloying elements which can be used for an estimation of mechanical properties taking into account complex influence of the main components of an alloy is offered for the first time. Since the dimensional mismatch of the lattice parameters is associated with the degree of concentration of solid-soluble hardening of γ- and γ'-phases, the efficiency of dispersion hardening of the alloy, creep rate and other properties, the obtained ratio allows to link these properties with multicomponent systems. Regression models are presented, with the help of which it is possible to calculate dimensional mismatch, strength, heat resistance, number of phases and density of alloys with high accuracy. The regularities of the composition influence on the properties of heat-resistant nickel alloys of directional crystallization are established. It is shown that for multicomponent nickel systems it is possible to predict with high probability misfit, which significantly affects the strength characteristics of alloys of this class. The decrease in the value of misfit is accompanied by an increase in the solubility of the elements in the -solid solution at a value of the ratio of alloying elements of 1.5 - 1.6. However, an increase in the ratio of alloying elements greater than 2 is accompanied by an increase in misfit, because the -solid solution has reached a maximum of dissolution. The perspective and effective direction in the decision of a problem of forecasting of the basic characteristics influencing a complex of service properties of alloys both at development of new heat-resistant nickel alloys, and at perfection of structures of known industrial marks of this class is shown. Keywords: nickel-based superalloys, dimensional mismatch (γ / γ'- mismatch), strength, heat resistance.","PeriodicalId":33600,"journal":{"name":"Metaloznavstvo ta obrobka metaliv","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41929678","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}
Z. Duriagina, I. Lemishka, O.S. Filimonov, A. Trostianchyn, V. Kulyk, L. Bohun
Specimens of titanium alloy VT8, which is used for the manufacture of gas turbine engine elements, were investigated in the initial state and after fracture toughness testing by methods of transmission electron microscopy and diffraction analysis. The features of the microstructure, structure morphology, the nature of phase distribution and structural components were established. Defects in the crystal structure, the formations of dislocation inhomogeneities and local concentrators of internal stresses were identified using JEM-200CX transmission electron microscope. The scalar dislocation density is determined by the secant method. The study of VT8 titanium alloy samples before and after destruction, which is used for the manufacture of GTE elements, using the methods of transmission electron microscopy and diffraction analysis was made. Microstructural investigations for a detailed analysis of the structure features, morphology and phase formations distribution, as well as their components establishment, the nature of crystal lattice defects, the formation of dislocation inhomogeneities and local concentrators of internal stresses were performed on a JEM-200CX transmission electron microscope. The scalar dislocation density was measured by the secant method. It is shown that the studied samples of VT8 titanium alloy are characterized by a two-phase (α + β) microstructure in the form of large -phase plates, 0.15 ... 0.76 μm in size, interspersed with an insignificant amount of thin-plate β-phase, with a size of 0.04 ... 0.21 μm. Based on scalar dislocation densities, the level of local internal stresses in the places of dislocation accumulations, which are sources of crack formation, was analytically estimated. Dispersed particles of secondary phases characterized by different sizes and different structure morphologies were identified. The calculated dislocation densities and an estimate of the average distance over which they move in the process of deformation are used as the basis for creating a statistical map of localized deformation level indicators in the alloy structural components and on the fracture surface. It is shown that as a result of fracture after testing for low-cycle fatigue, the dislocation density increases, the level of local internal stresses increases, and the formation of a cellular structure in the α- and β-phases and deformation grain-boundary defects occurs. Keywords: VT8 alloy, dislocation structure, microstructure, transmission electron microscopy, local internal stresses.
{"title":"Microstructure and dislocation hardening mechanism of VT8 alloy","authors":"Z. Duriagina, I. Lemishka, O.S. Filimonov, A. Trostianchyn, V. Kulyk, L. Bohun","doi":"10.15407/mom2021.03.022","DOIUrl":"https://doi.org/10.15407/mom2021.03.022","url":null,"abstract":"Specimens of titanium alloy VT8, which is used for the manufacture of gas turbine engine elements, were investigated in the initial state and after fracture toughness testing by methods of transmission electron microscopy and diffraction analysis. The features of the microstructure, structure morphology, the nature of phase distribution and structural components were established. Defects in the crystal structure, the formations of dislocation inhomogeneities and local concentrators of internal stresses were identified using JEM-200CX transmission electron microscope. The scalar dislocation density is determined by the secant method. The study of VT8 titanium alloy samples before and after destruction, which is used for the manufacture of GTE elements, using the methods of transmission electron microscopy and diffraction analysis was made. Microstructural investigations for a detailed analysis of the structure features, morphology and phase formations distribution, as well as their components establishment, the nature of crystal lattice defects, the formation of dislocation inhomogeneities and local concentrators of internal stresses were performed on a JEM-200CX transmission electron microscope. The scalar dislocation density was measured by the secant method. It is shown that the studied samples of VT8 titanium alloy are characterized by a two-phase (α + β) microstructure in the form of large -phase plates, 0.15 ... 0.76 μm in size, interspersed with an insignificant amount of thin-plate β-phase, with a size of 0.04 ... 0.21 μm. Based on scalar dislocation densities, the level of local internal stresses in the places of dislocation accumulations, which are sources of crack formation, was analytically estimated. Dispersed particles of secondary phases characterized by different sizes and different structure morphologies were identified. The calculated dislocation densities and an estimate of the average distance over which they move in the process of deformation are used as the basis for creating a statistical map of localized deformation level indicators in the alloy structural components and on the fracture surface. It is shown that as a result of fracture after testing for low-cycle fatigue, the dislocation density increases, the level of local internal stresses increases, and the formation of a cellular structure in the α- and β-phases and deformation grain-boundary defects occurs. Keywords: VT8 alloy, dislocation structure, microstructure, transmission electron microscopy, local internal stresses.","PeriodicalId":33600,"journal":{"name":"Metaloznavstvo ta obrobka metaliv","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46104196","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}
The work is devoted to the Al-10Mo electron-beam prepared master-alloy modifying phases dissolution and assimilation features determination. It is shown that the obtained master-alloy is characterized by uniform distribution and high dispersion of molybdenum aluminide particles. When studying the process of dissolving the master-alloy in pure aluminum, it was determined that the time of modification of the melt more than 20 minutes at a temperature of 740 ± 10 ° C leads to the most complete destruction of the original intermetallics Al22Mo5 and Al17Mo4 and the formation of smaller and evenly distributed particles Al5Mo and Al12Mo with dimensions about 2 μm. As the molybdenum content decreases, the dispersion of the modifying phases and the uniformity of their distribution increase. Increasing the temperature and exposure time do not improve the assimilation of the modifier. The Al-10Mo master-alloy, obtained in the conditions of electron-beam casting technology, has a number of characteristics that allow to consider it as more efficient and cost-effective, compared to known analogues. This is due to the much higher concentration of molybdenum in the modifier (10% wt.), as well as fine dispersion and uniform distribution of the modifying phases. The nonequilibrium composition of aluminides inherent in the ligatures obtained under these conditions contributes to their significant grinding and refining after addition into aluminum melts. The stoichiometry of the phases from Al22Mo5 and Al17Mo4 changes to Al12Mo, which serve as crystallization centers and have a size of about 1 μm, dissolves and changes. The example of industrial casting alloy AlSi9Cu3 shows complete and effective assimilation of the master-alloy in a short time of 5 minutes at a temperature of 740 ± 10 ° C. Such indicators are more economic, in comparison with standard industrial ones, for which both higher temperature of melt preparing ant longer lifetime in liquid state after modification are necessary. Keywords: master-alloys, Al-Mo, modifications, aluminum alloys, AlSi9Cu3, resource saving.
{"title":"Features of Al-10Mo electron-beam produced master-alloy assimilation in liquid aluminum and AlSi9Cu3 alloy","authors":"M. Voron, M. Fon Pruss","doi":"10.15407/mom2021.03.049","DOIUrl":"https://doi.org/10.15407/mom2021.03.049","url":null,"abstract":"The work is devoted to the Al-10Mo electron-beam prepared master-alloy modifying phases dissolution and assimilation features determination. It is shown that the obtained master-alloy is characterized by uniform distribution and high dispersion of molybdenum aluminide particles. When studying the process of dissolving the master-alloy in pure aluminum, it was determined that the time of modification of the melt more than 20 minutes at a temperature of 740 ± 10 ° C leads to the most complete destruction of the original intermetallics Al22Mo5 and Al17Mo4 and the formation of smaller and evenly distributed particles Al5Mo and Al12Mo with dimensions about 2 μm. As the molybdenum content decreases, the dispersion of the modifying phases and the uniformity of their distribution increase. Increasing the temperature and exposure time do not improve the assimilation of the modifier. The Al-10Mo master-alloy, obtained in the conditions of electron-beam casting technology, has a number of characteristics that allow to consider it as more efficient and cost-effective, compared to known analogues. This is due to the much higher concentration of molybdenum in the modifier (10% wt.), as well as fine dispersion and uniform distribution of the modifying phases. The nonequilibrium composition of aluminides inherent in the ligatures obtained under these conditions contributes to their significant grinding and refining after addition into aluminum melts. The stoichiometry of the phases from Al22Mo5 and Al17Mo4 changes to Al12Mo, which serve as crystallization centers and have a size of about 1 μm, dissolves and changes. The example of industrial casting alloy AlSi9Cu3 shows complete and effective assimilation of the master-alloy in a short time of 5 minutes at a temperature of 740 ± 10 ° C. Such indicators are more economic, in comparison with standard industrial ones, for which both higher temperature of melt preparing ant longer lifetime in liquid state after modification are necessary. Keywords: master-alloys, Al-Mo, modifications, aluminum alloys, AlSi9Cu3, resource saving.","PeriodicalId":33600,"journal":{"name":"Metaloznavstvo ta obrobka metaliv","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41721728","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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