Using the method of mathematical planning of the experiment, the influence of two-stage (low-temperature + high-temperature) aging on the hardness and high-temperature (750 °C) impact strength of a stamped alloy ХН35ВТЮ (EK39) for hot pressing of metals was investigated. The need to increase the high-temperature impact strength of the alloy is a significant decrease (failure) with increasing test temperature from room temperature to 700… 750 °C. To isolate the particles of the reinforcing γ′-phase of the Ni3(Al,Ti) type during aging, the alloy was previously hardened in oil from a temperature of 1150 °C. Determination of the most effective modes of two-stage aging was performed using a small replica of the orthogonal plan of the second order type 24-1. The first (low-temperature) stage corresponds to the beginning of spinodal decay of supersaturated solid solution at the stage of formation of Guinness-Preston zones, and the second (high-temperature) - to the formation of particles of stable γ′-phase type Ni3(Ti,Al). Temperature and aging time on each step varied. According to the planning matrix, regression equations were calculated, and additional experiments were performed to determine the modes of step aging, which provide the alloy with a higher level of selected properties compared to the recommended single aging (780 °C, 10 hours). According to the obtained regression equations, the change in the aging temperature at the second stage of aging does not affect the hardness of the alloy within its variation (750 °C–800 °C). The effect on impact strength of changes in temperature (650 °C–700 °C) and holding time (2–6 hours) at the first stage of aging is also insignificant. According to the results of processing and analysis of experimental data, it is established that the increase of high-temperature impact strength from 38 to 120 J/cm2 (while maintaining hardness and high-temperature strength at the same level) is achieved after step aging 700 °C, 20 hours + 750 °C, 2 hours. The increase in hardness from 29 to 33 HRC with a simultaneous increase in impact strength to 55 J/cm2 provides step aging of 725 °C, 10 hours + 775 °C, 6 hours. According to the results of electron microscopic study of the microstructure, it was found that the achieved level of impact strength after step aging is provided by increasing the dispersion of spherical particles of the γ′-phase of the type Ni3(Al,Ti). The increase in hardness is due to a more uniform volume distribution and a smaller cross-sectional scatter of γ′-phase particles. Keywords: aging, dispersion hardening, impact strength, microstructure, stamping tool.
{"title":"Determination of step aging effective modes of a stamped alloy for hot deformation","authors":"V.Ya. Grabovsky, V. Kanyuka, O. Lysytsia","doi":"10.15407/mom2021.03.032","DOIUrl":"https://doi.org/10.15407/mom2021.03.032","url":null,"abstract":"Using the method of mathematical planning of the experiment, the influence of two-stage (low-temperature + high-temperature) aging on the hardness and high-temperature (750 °C) impact strength of a stamped alloy ХН35ВТЮ (EK39) for hot pressing of metals was investigated. The need to increase the high-temperature impact strength of the alloy is a significant decrease (failure) with increasing test temperature from room temperature to 700… 750 °C. To isolate the particles of the reinforcing γ′-phase of the Ni3(Al,Ti) type during aging, the alloy was previously hardened in oil from a temperature of 1150 °C. Determination of the most effective modes of two-stage aging was performed using a small replica of the orthogonal plan of the second order type 24-1. The first (low-temperature) stage corresponds to the beginning of spinodal decay of supersaturated solid solution at the stage of formation of Guinness-Preston zones, and the second (high-temperature) - to the formation of particles of stable γ′-phase type Ni3(Ti,Al). Temperature and aging time on each step varied. According to the planning matrix, regression equations were calculated, and additional experiments were performed to determine the modes of step aging, which provide the alloy with a higher level of selected properties compared to the recommended single aging (780 °C, 10 hours). According to the obtained regression equations, the change in the aging temperature at the second stage of aging does not affect the hardness of the alloy within its variation (750 °C–800 °C). The effect on impact strength of changes in temperature (650 °C–700 °C) and holding time (2–6 hours) at the first stage of aging is also insignificant. According to the results of processing and analysis of experimental data, it is established that the increase of high-temperature impact strength from 38 to 120 J/cm2 (while maintaining hardness and high-temperature strength at the same level) is achieved after step aging 700 °C, 20 hours + 750 °C, 2 hours. The increase in hardness from 29 to 33 HRC with a simultaneous increase in impact strength to 55 J/cm2 provides step aging of 725 °C, 10 hours + 775 °C, 6 hours. According to the results of electron microscopic study of the microstructure, it was found that the achieved level of impact strength after step aging is provided by increasing the dispersion of spherical particles of the γ′-phase of the type Ni3(Al,Ti). The increase in hardness is due to a more uniform volume distribution and a smaller cross-sectional scatter of γ′-phase particles. Keywords: aging, dispersion hardening, impact strength, microstructure, stamping tool.","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":"49070200","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 results of research of structural steel brand 4Kh4N5М4F2 after heat treatment are given. Manifestations of tempering brittleness at a temperature of 450-500 °C, associated with the maximum value of the parameter «a» of the crystal structure during the formation of a solid substitution solution in the system "Fe-C". The connection between the peculiarities of the crystal structure of the studied steel and the complex of physical and mechanical properties is established. The maximum value of the parameter «а» (a = 0.28848 nm) of the elementary cell of martensite crystal lattice reflects the maximum saturation of the α-solid solution, which increases the resistance of the crystal lattice to deformation, increase the hardness of tempering martensite (up to 56 HRC), change the physical structure sensitive value (increase in specific conductivity to 0,200 Om•mm2/m), increase the tensile strength, reduce the impact strength (up to 15 J/cm2) and increase the brittleness at temperatures of 450-500 °C. The possibility of using matrices (steel 4Kh4N5М4F2, without forging technology) for hot deformation of aluminum alloy AK7ch, which during operation does not reach the temperature of brittleness (above 460 ºC), is demonstrated. Keywords: die steel, crystal structure, heat treatment, physical and mechanical properties.
{"title":"Tempering brittleness of die steel 4Kh4N5М4F2","authors":"O. Sydorchuk, O. Bykov, A. P. Pozniy","doi":"10.15407/mom2021.03.057","DOIUrl":"https://doi.org/10.15407/mom2021.03.057","url":null,"abstract":"The results of research of structural steel brand 4Kh4N5М4F2 after heat treatment are given. Manifestations of tempering brittleness at a temperature of 450-500 °C, associated with the maximum value of the parameter «a» of the crystal structure during the formation of a solid substitution solution in the system \"Fe-C\". The connection between the peculiarities of the crystal structure of the studied steel and the complex of physical and mechanical properties is established. The maximum value of the parameter «а» (a = 0.28848 nm) of the elementary cell of martensite crystal lattice reflects the maximum saturation of the α-solid solution, which increases the resistance of the crystal lattice to deformation, increase the hardness of tempering martensite (up to 56 HRC), change the physical structure sensitive value (increase in specific conductivity to 0,200 Om•mm2/m), increase the tensile strength, reduce the impact strength (up to 15 J/cm2) and increase the brittleness at temperatures of 450-500 °C. The possibility of using matrices (steel 4Kh4N5М4F2, without forging technology) for hot deformation of aluminum alloy AK7ch, which during operation does not reach the temperature of brittleness (above 460 ºC), is demonstrated. Keywords: die steel, crystal structure, heat treatment, physical and mechanical properties.","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":"47441166","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 results of the study of the influence of nickel and molybdenum on the structure and chemical composition of the fracture surface of cast iron with spherical graphite are presented in the paper. It is shown that the fracture of cast iron with spherical graphite occurs along the boundaries of the distribution of graphite balls with matrix, and the fracture of the matrix occurs both by the mechanism of intergranular and transgranular fractures. Molybdenum and nickel alloying changes the mechanism of transgranular fracture of the matrix from brittle for ordinary cast iron to viscous for molybdenum and nickel alloying. It is established that the fracture surfaces of cast iron, depending on the analysis places there are elements such as O, C, P, N, Cu, Ni, Si, Mg. Studies of the distribution of impurities in the near-surface layers of the destroyed samples have shown that the quantity of elements such as oxygen, phosphorus and nitrogen decreases with increasing distance from the fracture surface. The phosphorus quantity is reduced by 40 - 45% in the places of the cast iron matrix, where the graphite balls were located during the alloying of cast iron by molybdenum and nickel. Keywords: cast iron, nickel, molybdenum, alloying, Auger spectroscopy, chemical composition, structure, fracture, surface.
{"title":"Nickel and molybdenum influence on the structure and chemical composition of surface destruction of iron with spherical graphite","authors":"Y. Aftandiliants","doi":"10.15407/mom2021.03.040","DOIUrl":"https://doi.org/10.15407/mom2021.03.040","url":null,"abstract":"The results of the study of the influence of nickel and molybdenum on the structure and chemical composition of the fracture surface of cast iron with spherical graphite are presented in the paper. It is shown that the fracture of cast iron with spherical graphite occurs along the boundaries of the distribution of graphite balls with matrix, and the fracture of the matrix occurs both by the mechanism of intergranular and transgranular fractures. Molybdenum and nickel alloying changes the mechanism of transgranular fracture of the matrix from brittle for ordinary cast iron to viscous for molybdenum and nickel alloying. It is established that the fracture surfaces of cast iron, depending on the analysis places there are elements such as O, C, P, N, Cu, Ni, Si, Mg. Studies of the distribution of impurities in the near-surface layers of the destroyed samples have shown that the quantity of elements such as oxygen, phosphorus and nitrogen decreases with increasing distance from the fracture surface. The phosphorus quantity is reduced by 40 - 45% in the places of the cast iron matrix, where the graphite balls were located during the alloying of cast iron by molybdenum and nickel. Keywords: cast iron, nickel, molybdenum, alloying, Auger spectroscopy, chemical composition, structure, fracture, surface.","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":"44249625","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, G. I. Shevchenko
The influence of melt overheating in the range of 50-150 °C on the equilibrium liquidus and its cooling rate during crystallization of castings on the formation of macrostructural zones along their cross section, on the change of grain dispersion, dendritic structure characteristics and mechanical properties was investigated on the example of 25L steel. It is established that the macrostructure of castings in the direction of unilateral heat removal as it moves away from the cooled surface consists of four main structural zones - small coaxial crystals, columnar, branched and large coaxial crystals, the length and morphology of which naturally change depending on thermokinetic conditions of crystallization. The decisive role of the cooling rate at significant overheating of the melt to increase the number of crystallization nuclei, the formation of a more dispersed cast structure by increasing the degree of supercooling of the melt during crystallization is shown. The regularities of quantitative characteristics change of microstructure and dendritic structure depending on change of temperature-time parameters of crystallization in different structural zones of castings and their connection with characteristics of mechanical properties of steel are established. On the basis of mathematical processing of experimental data by linear regression analysis interpolation models and their graphical interpretations are obtained, which allow to quantify and predict the change of mechanical properties in different structural zones of gradient castings depending on melt overheating temperature and cooling modes within the investigated factor space. Keywords: gradient structure, structural zones, melt, mechanical properties.
{"title":"Gradient structure and properties of steel castings","authors":"S. Kondratyuk, V. I. Veis, Z. Parkhomchuk, G. I. Shevchenko","doi":"10.15407/mom2021.03.003","DOIUrl":"https://doi.org/10.15407/mom2021.03.003","url":null,"abstract":"The influence of melt overheating in the range of 50-150 °C on the equilibrium liquidus and its cooling rate during crystallization of castings on the formation of macrostructural zones along their cross section, on the change of grain dispersion, dendritic structure characteristics and mechanical properties was investigated on the example of 25L steel. It is established that the macrostructure of castings in the direction of unilateral heat removal as it moves away from the cooled surface consists of four main structural zones - small coaxial crystals, columnar, branched and large coaxial crystals, the length and morphology of which naturally change depending on thermokinetic conditions of crystallization. The decisive role of the cooling rate at significant overheating of the melt to increase the number of crystallization nuclei, the formation of a more dispersed cast structure by increasing the degree of supercooling of the melt during crystallization is shown. The regularities of quantitative characteristics change of microstructure and dendritic structure depending on change of temperature-time parameters of crystallization in different structural zones of castings and their connection with characteristics of mechanical properties of steel are established. On the basis of mathematical processing of experimental data by linear regression analysis interpolation models and their graphical interpretations are obtained, which allow to quantify and predict the change of mechanical properties in different structural zones of gradient castings depending on melt overheating temperature and cooling modes within the investigated factor space. Keywords: gradient structure, structural zones, melt, mechanical properties.","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":"49576237","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}
M. D. Аikin, V. Shalomeev, É. Tsivirko, Zaporizhzhya Polytechnic, Ukraine Zaporozhye
{"title":"Biosoluble magnesium-based alloy for medical purposes","authors":"M. D. Аikin, V. Shalomeev, É. Tsivirko, Zaporizhzhya Polytechnic, Ukraine Zaporozhye","doi":"10.15407/mom2019.04.038","DOIUrl":"https://doi.org/10.15407/mom2019.04.038","url":null,"abstract":"","PeriodicalId":33600,"journal":{"name":"Metaloznavstvo ta obrobka metaliv","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45997703","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.Ya. Shypytsyn, I. F. Kirchu, T. Stepanova, S. Kucherenko
{"title":"Mechanical and functional properties of Cr-(Ni)-Mn-N austenitic heat-resistant steels","authors":"S.Ya. Shypytsyn, I. F. Kirchu, T. Stepanova, S. Kucherenko","doi":"10.15407/mom2019.03.023","DOIUrl":"https://doi.org/10.15407/mom2019.03.023","url":null,"abstract":"","PeriodicalId":33600,"journal":{"name":"Metaloznavstvo ta obrobka metaliv","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42445801","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}
{"title":"Artificial neural networks using for solving of the tribological problems","authors":"V. Uvarov, S. Bespalov","doi":"10.15407/mom2019.03.003","DOIUrl":"https://doi.org/10.15407/mom2019.03.003","url":null,"abstract":"","PeriodicalId":33600,"journal":{"name":"Metaloznavstvo ta obrobka metaliv","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42774162","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}
{"title":"Application of the method of fractal analysis to the study of metal structure","authors":"O. O. Shyofel, Kyiv Ukraine","doi":"10.15407/mom2019.03.040","DOIUrl":"https://doi.org/10.15407/mom2019.03.040","url":null,"abstract":"","PeriodicalId":33600,"journal":{"name":"Metaloznavstvo ta obrobka metaliv","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44619411","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, A. Nuradinov, Z. Parkhomchuk, V. I. Veis
Методом фізичного моделювання з використанням прозорого модельного матеріалу (камфен 90 % + трициклен 10 %) досліджено вплив температури перегріву розплаву над рівноважним ліквідусом і швидкості охолодження його під час кристалізації, вплив температури ізотермічної обробки розплаву у передкристалізаційний період і в температурному інтервалі кристалізації за умов нормального і швидкісного тепловідбору на процеси формування литої структури. Встановлено, що утворення грубозернистої структури при значному перегріві розплаву може бути усунено швидкісним його охолодженням при кристалізації, що забезпечує формування дрібнозернистої структури з високою дисперсністю дендритної будови. Показано, що у вузькому інтервалі температур у підліквідусній області під час ізотермічної обробки розплаву утворюються і накопичуються кристали твердої фази без суттєвого збільшення їх розмірів, забезпечуючи формування дисперсної литої структури при наступному швидкісному охолодженні розплаву. Ключові слова: фізичне моделювання, ліквідус, температура перегріву, кристалізація, структуроутворення, ізотермічна обробка.
{"title":"Formation of cast structure in relation to temperature and time parameters of melting and crystallization","authors":"S. Kondratyuk, A. Nuradinov, Z. Parkhomchuk, V. I. Veis","doi":"10.15407/mom2019.03.030","DOIUrl":"https://doi.org/10.15407/mom2019.03.030","url":null,"abstract":"Методом фізичного моделювання з використанням прозорого модельного матеріалу (камфен 90 % + трициклен 10 %) досліджено вплив температури перегріву розплаву над рівноважним ліквідусом і швидкості охолодження його під час кристалізації, вплив температури ізотермічної обробки розплаву у передкристалізаційний період і в температурному інтервалі кристалізації за умов нормального і швидкісного тепловідбору на процеси формування литої структури. Встановлено, що утворення грубозернистої структури при значному перегріві розплаву може бути усунено швидкісним його охолодженням при кристалізації, що забезпечує формування дрібнозернистої структури з високою дисперсністю дендритної будови. Показано, що у вузькому інтервалі температур у підліквідусній області під час ізотермічної обробки розплаву утворюються і накопичуються кристали твердої фази без суттєвого збільшення їх розмірів, забезпечуючи формування дисперсної литої структури при наступному швидкісному охолодженні розплаву. Ключові слова: фізичне моделювання, ліквідус, температура перегріву, кристалізація, структуроутворення, ізотермічна обробка.","PeriodicalId":33600,"journal":{"name":"Metaloznavstvo ta obrobka metaliv","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42665563","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}
{"title":"Peculiarities of qualitative indicators of metal of the forged boiler tuber","authors":"L. Opryshko, T. Golovnyak","doi":"10.15407/mom2019.03.047","DOIUrl":"https://doi.org/10.15407/mom2019.03.047","url":null,"abstract":"","PeriodicalId":33600,"journal":{"name":"Metaloznavstvo ta obrobka metaliv","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43665247","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：