Pub Date : 2021-09-30DOI: 10.18323/2073-5073-2021-3-67-73
L. Rezyapova, R. Valiev, E. I. Usmanov, R. Valiev
It is known that titanium and its alloys are one of the promising materials in the industry, especially in medicine, due to their excellent biocompatibility and corrosion resistance. The latest modern equipment and instruments used in traumatology, orthopedics, dentistry, etc. demand increasingly higher mechanical properties for materials. In comparison with commercially pure titanium, alloys do not have such high corrosion-resistant properties and biocompatibility. In this regard, improving the mechanical characteristics of a pure material is an urgent issue. The authors studied the effect of annealing on the structure and properties of commercially pure grade 4 titanium in the coarse-grained and ultrafine-grained states. The ultrafine-grained state was obtained using high-pressure torsion (HPT) under the pressure of 6 GPa at N=10 revolutions at room temperature. In the microstructure investigated using transmission electron microscopy, the authors could detect particles of precipitated phases after annealing, which had different morphologies. Deformation leads to an increase in the precipitated particles after annealing. The authors carried out an X-ray phase analysis, which showed the approximation of the lattice parameters of the α-phase after deformation and annealing at 700 °C to the values of the parameters of pure titanium. Thus, aging processes occur in the material, accompanied by the decomposition of the supersaturated solid solution and the release of particles of the second phase. The paper shows the results of titanium microhardness measurements in different states. The combined treatment, consisting of HPT at N=5 revolutions, annealing at 700 °C, and additional HPT deformation at N=5 revolutions, allowed obtaining the record strength for commercially pure grade 4 titanium.
{"title":"THE RESEARCH OF AGING AND MECHANICAL PROPERTIES OF NANOSTRUCTURAL TITANIUM","authors":"L. Rezyapova, R. Valiev, E. I. Usmanov, R. Valiev","doi":"10.18323/2073-5073-2021-3-67-73","DOIUrl":"https://doi.org/10.18323/2073-5073-2021-3-67-73","url":null,"abstract":"It is known that titanium and its alloys are one of the promising materials in the industry, especially in medicine, due to their excellent biocompatibility and corrosion resistance. The latest modern equipment and instruments used in traumatology, orthopedics, dentistry, etc. demand increasingly higher mechanical properties for materials. In comparison with commercially pure titanium, alloys do not have such high corrosion-resistant properties and biocompatibility. In this regard, improving the mechanical characteristics of a pure material is an urgent issue. The authors studied the effect of annealing on the structure and properties of commercially pure grade 4 titanium in the coarse-grained and ultrafine-grained states. The ultrafine-grained state was obtained using high-pressure torsion (HPT) under the pressure of 6 GPa at N=10 revolutions at room temperature. In the microstructure investigated using transmission electron microscopy, the authors could detect particles of precipitated phases after annealing, which had different morphologies. Deformation leads to an increase in the precipitated particles after annealing. The authors carried out an X-ray phase analysis, which showed the approximation of the lattice parameters of the α-phase after deformation and annealing at 700 °C to the values of the parameters of pure titanium. Thus, aging processes occur in the material, accompanied by the decomposition of the supersaturated solid solution and the release of particles of the second phase. The paper shows the results of titanium microhardness measurements in different states. The combined treatment, consisting of HPT at N=5 revolutions, annealing at 700 °C, and additional HPT deformation at N=5 revolutions, allowed obtaining the record strength for commercially pure grade 4 titanium.","PeriodicalId":23555,"journal":{"name":"Vektor nauki Tol'yattinskogo gosudarstvennogo universiteta","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85661065","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 : 2021-01-01DOI: 10.18323/2073-5073-2021-1-7-15
S. Ermakov
Additive technologies are among the most rapidly developing areas of modern production. To ensure the progressive movement of additive technologies development in the Russian Federation, it is necessary to provide maximum availability of additive raw materials – spherical metal powders for the domestic enterprises; however, the absence of domestic assemblies to produce such powders hampers the solution of this issue. Peter the Great St. Petersburg Polytechnic University has developed and successfully carried out industrial tests of a plasma atomization system for solid metal feedstocks of various chemical compositions. The paper presents the results of the study of the influence of some technological parameters on the granulometric size, shape, and defect structure of 12H18N9 steel and VG98 alloy powders. The paper includes the results of the research of the influence of such spraying parameters as the current strength and the plasma-forming gas velocity supplied to the plasma generator and the volume of protective gas supplied to the spray torch through the fluidized bed system nozzles located in the midsection of the atomizer spraying chamber. The study showed that by increasing the current strength and the plasma-forming gas velocity, it is possible to reduce the average size of the powder particles; and by changing the volume of the protective gas supply, it is possible to control the particle shape. The analysis of the chemical composition of the obtained powders shows that during the spraying process, there is no loss of alloying elements and the powder composition is the same as the original feedstock compositions. The paper gives the developed modes for the alloy feedstocks spraying, shows the possibility to produce metal powders with the level of the spherical shape factor of 92–96 % and minimal – not exceeding 0.5 % of powder aggregate weight – number of particles with nonmetallic inclusions, external and internal defects.
{"title":"Regulation of powder particles shape and size at plasma spraying","authors":"S. Ermakov","doi":"10.18323/2073-5073-2021-1-7-15","DOIUrl":"https://doi.org/10.18323/2073-5073-2021-1-7-15","url":null,"abstract":"Additive technologies are among the most rapidly developing areas of modern production. To ensure the progressive movement of additive technologies development in the Russian Federation, it is necessary to provide maximum availability of additive raw materials – spherical metal powders for the domestic enterprises; however, the absence of domestic assemblies to produce such powders hampers the solution of this issue. Peter the Great St. Petersburg Polytechnic University has developed and successfully carried out industrial tests of a plasma atomization system for solid metal feedstocks of various chemical compositions. The paper presents the results of the study of the influence of some technological parameters on the granulometric size, shape, and defect structure of 12H18N9 steel and VG98 alloy powders. The paper includes the results of the research of the influence of such spraying parameters as the current strength and the plasma-forming gas velocity supplied to the plasma generator and the volume of protective gas supplied to the spray torch through the fluidized bed system nozzles located in the midsection of the atomizer spraying chamber. The study showed that by increasing the current strength and the plasma-forming gas velocity, it is possible to reduce the average size of the powder particles; and by changing the volume of the protective gas supply, it is possible to control the particle shape. The analysis of the chemical composition of the obtained powders shows that during the spraying process, there is no loss of alloying elements and the powder composition is the same as the original feedstock compositions. The paper gives the developed modes for the alloy feedstocks spraying, shows the possibility to produce metal powders with the level of the spherical shape factor of 92–96 % and minimal – not exceeding 0.5 % of powder aggregate weight – number of particles with nonmetallic inclusions, external and internal defects.","PeriodicalId":23555,"journal":{"name":"Vektor nauki Tol'yattinskogo gosudarstvennogo universiteta","volume":"24 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75685070","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 : 2021-01-01DOI: 10.18323/2073-5073-2021-2-47-56
M. Seleznev, A. Vinogradov
The ultrasonic fatigue testing (USFT) is an effective method for rapid determination of the fatigue properties of structural materials under high cycle (≥106 cycles) loading. However, the occurrence and accumulation of fatigue damage with this test method remain uncertain due to the limitations of the existing measurement methods. Currently used monitoring methods allow detecting the fatigue cracks, but only in the late stages of failure. Despite the superior sensitivity to localized processes in materials, the use of the acoustic emission (AE) method in ultrasonic testing is extremely difficult due to the presence of resonant noise. This work aimed to suppress resonant noise and extract the signal for early detection of fatigue damage. The authors tested the samples of the AlSi9Cu3 aluminum alloy under the asymmetric cyclic loading (R=0.1) at a resonant frequency of 19.5 kHz with a non-threshold AE registration. The fracture surfaces were analyzed by electron and optical microscopy. The authors processed AE by two different methods: (1) the digital filtering method consisted of detecting resonant noise and removing it from the spectrum; (2) the φ-function method consisted of differentiating the spectrogram by time. The processed spectrograms were integrated by the frequency with further extraction of the AE events using the threshold method. The digital filtering method revealed a correlation between AE signals and fatigue damage, whereas the undamaged control sample showed no signals. The φ-function technique demonstrated ambiguous results, showing high AE activity on the control sample.
{"title":"The application of acoustic emission method for ultrasonic fatigue testing monitoring","authors":"M. Seleznev, A. Vinogradov","doi":"10.18323/2073-5073-2021-2-47-56","DOIUrl":"https://doi.org/10.18323/2073-5073-2021-2-47-56","url":null,"abstract":"The ultrasonic fatigue testing (USFT) is an effective method for rapid determination of the fatigue properties of structural materials under high cycle (≥106 cycles) loading. However, the occurrence and accumulation of fatigue damage with this test method remain uncertain due to the limitations of the existing measurement methods. Currently used monitoring methods allow detecting the fatigue cracks, but only in the late stages of failure. Despite the superior sensitivity to localized processes in materials, the use of the acoustic emission (AE) method in ultrasonic testing is extremely difficult due to the presence of resonant noise. This work aimed to suppress resonant noise and extract the signal for early detection of fatigue damage. The authors tested the samples of the AlSi9Cu3 aluminum alloy under the asymmetric cyclic loading (R=0.1) at a resonant frequency of 19.5 kHz with a non-threshold AE registration. The fracture surfaces were analyzed by electron and optical microscopy. The authors processed AE by two different methods: (1) the digital filtering method consisted of detecting resonant noise and removing it from the spectrum; (2) the φ-function method consisted of differentiating the spectrogram by time. The processed spectrograms were integrated by the frequency with further extraction of the AE events using the threshold method. The digital filtering method revealed a correlation between AE signals and fatigue damage, whereas the undamaged control sample showed no signals. The φ-function technique demonstrated ambiguous results, showing high AE activity on the control sample.","PeriodicalId":23555,"journal":{"name":"Vektor nauki Tol'yattinskogo gosudarstvennogo universiteta","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89626087","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 : 2021-01-01DOI: 10.18323/2073-5073-2021-3-57-66
V. Moskvina, E. Melnikov, E. Zagibalova
The main problem of additively manufactured chromium-nickel austenitic stainless steels is the formation of a two-phase γ-austenite/δ-ferrite dendritic microstructure, which complicates their use and distinguishes them from cast single-phase analogs. The reasons for the formation of a two-phase structure are nonequilibrium solidification conditions, complex thermal history, and melt depletion by austenite-forming elements (nickel and manganese). Therefore, additional nickel alloying under the additive manufacturing of steels can stabilize the austenitic structure in them. In this work, the authors used electron-beam additive production with simultaneous feeding of two wires from austenitic stainless steel Fe-18.2Cr-9.5Ni-1.1Mn-0.7Ti-0.5Si-0.08C wt.% (SS, Cr18Ni10Ti) and alloy 77.7Ni-19.6Cr-1.8Si-0.5Fe-0.4Zr wt.% (Ni-Cr alloy, Cr20Ni80) to obtain two gradient billets. The authors used two wire-feeding strategies (the first one is four layers of SS/one layer of Cr20Ni80; the second one is one layer of SS/one layer of a mixture 80 % SS + 20 % Cr20Ni80). The study identified that the Ni-Cr alloying in the process of electron-beam additive production of SS billets suppressed δ-ferrite formation and contributes to the stabilization of the austenite phase. The deposition of Ni-Cr alloy next to the four layers of SS leads to inhomogeneity of the structure and chemical composition in the billet, low plasticity, and premature failure of these specimens during tensile tests. The sequential alternation of pure SS layers with those of a mixture of wires (80 % SS + 20 % Cr20Ni80) promotes the uniform mixing of two wires components and the formation of a more homogeneous structure in the gradient billet, which leads to an increase in the ductility of the specimens during mechanical tests.
增材制造铬镍奥氏体不锈钢的主要问题是两相γ-奥氏体/δ-铁素体枝晶组织的形成，这使其使用复杂化，并使其与铸造的单相类似物区别开来。形成两相结构的原因是不平衡凝固条件、复杂的热历史和奥氏体形成元素(镍和锰)的熔体耗损。因此，在钢的增材制造中添加镍合金可以稳定钢的奥氏体组织。本文采用电子束增材生产的方法，同时喂入奥氏体不锈钢Fe-18.2Cr-9.5Ni-1.1Mn-0.7Ti-0.5Si-0.08C wt.% (SS, Cr18Ni10Ti)和合金77.7Ni-19.6Cr-1.8Si-0.5Fe-0.4Zr wt.% (Ni-Cr alloy, Cr20Ni80)两种钢丝，得到两种梯度坯。作者采用了两种送丝策略(第一种是四层SS/一层Cr20Ni80;第二种是一层SS/一层80% SS + 20% Cr20Ni80的混合物)。研究发现，在电子束添加剂生产SS方坯的过程中，Ni-Cr合金抑制了δ-铁素体的形成，有助于奥氏体相的稳定。Ni-Cr合金在四层SS旁的沉积导致坯料组织和化学成分不均匀，塑性低，在拉伸试验中过早失效。纯SS层与混合丝层(80% SS + 20% Cr20Ni80)的顺序交替促进了两种丝成分的均匀混合，并在梯度坯料中形成了更均匀的组织，从而导致力学试验中试样的延展性增加。
{"title":"CHARACTERISTICS OF A GRADIENT MATERIAL BASED ON NI-CR STAINLESS STEEL AND H20N80 ALLOY PRODUCED BY ELECTRON-BEAM 3D-PRINTING","authors":"V. Moskvina, E. Melnikov, E. Zagibalova","doi":"10.18323/2073-5073-2021-3-57-66","DOIUrl":"https://doi.org/10.18323/2073-5073-2021-3-57-66","url":null,"abstract":"The main problem of additively manufactured chromium-nickel austenitic stainless steels is the formation of a two-phase γ-austenite/δ-ferrite dendritic microstructure, which complicates their use and distinguishes them from cast single-phase analogs. The reasons for the formation of a two-phase structure are nonequilibrium solidification conditions, complex thermal history, and melt depletion by austenite-forming elements (nickel and manganese). Therefore, additional nickel alloying under the additive manufacturing of steels can stabilize the austenitic structure in them. In this work, the authors used electron-beam additive production with simultaneous feeding of two wires from austenitic stainless steel Fe-18.2Cr-9.5Ni-1.1Mn-0.7Ti-0.5Si-0.08C wt.% (SS, Cr18Ni10Ti) and alloy 77.7Ni-19.6Cr-1.8Si-0.5Fe-0.4Zr wt.% (Ni-Cr alloy, Cr20Ni80) to obtain two gradient billets. The authors used two wire-feeding strategies (the first one is four layers of SS/one layer of Cr20Ni80; the second one is one layer of SS/one layer of a mixture 80 % SS + 20 % Cr20Ni80). The study identified that the Ni-Cr alloying in the process of electron-beam additive production of SS billets suppressed δ-ferrite formation and contributes to the stabilization of the austenite phase. The deposition of Ni-Cr alloy next to the four layers of SS leads to inhomogeneity of the structure and chemical composition in the billet, low plasticity, and premature failure of these specimens during tensile tests. The sequential alternation of pure SS layers with those of a mixture of wires (80 % SS + 20 % Cr20Ni80) promotes the uniform mixing of two wires components and the formation of a more homogeneous structure in the gradient billet, which leads to an increase in the ductility of the specimens during mechanical tests.","PeriodicalId":23555,"journal":{"name":"Vektor nauki Tol'yattinskogo gosudarstvennogo universiteta","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89929567","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 : 2021-01-01DOI: 10.18323/2073-5073-2021-3-28-36
A. Valeeva, E. Gotlib, E. Yamaleeva
The use of epoxy antifriction coatings can significantly reduce thermal stress in the friction zone and expand the coating working temperature interval while keeping high wear resistance. The paper considers the effect of non-activated and activated by surfactants silicate filler – rice husk ash on the physicochemical and mechanical properties of epoxy materials applied as antifriction coatings. All studied samples of rice husk ash, both initial and activated with surfactants, have an alkaline surface nature. The study identified that all cationic quaternary ammonium salts (QAS) reduce the pH of rice husk ash. At the same time, nonionic OXIPAV increases this indicator. Activation of the rice husk ash surface, both by the quaternary ammonium salts and aminosilanes, significantly reduces the porosity of this silicate. In this case, the average pore diameter does not change significantly, and their specific surface area decreases significantly, to a lesser extent, when activated by nonionic quaternary ammonium salts. The application of quaternary ammonium salts and aminosilanes in the amount of 33 % for activation of the surface of the investigated silicate filler reduces its modifying effect in epoxy compositions, regardless of the chemical structure of the surfactants used, which is not a typical effect. Therefore, the authors assumed that the suboptimal concentration of quaternary ammonium salts and aminosilanes was used. The study identified that the optimal concentration of 50 % alcohol solution of KATAPAV is 14.7–21 %. In this range of the QAS content, there is a significant increase in hardness (about 40 %), a slight decrease in wear (about 10 %), and a significant decrease in the coefficient of static friction (up to 2 times). At the same time, the authors observed an increase in adhesion to metal up to 3 times and bending strength up to 25 %. Thus, rice husk ash activated with an optimal amount of quaternary ammonium salts is an effective modifier of epoxy coatings, which improves their antifriction properties and increases wear resistance, hardness, strength, and adhesion characteristics.
{"title":"EPOXY ANTIFRICTION COATINGS FILLED WITH THE RICE HUSKS ASH TREATED WITH SURFACTANTS","authors":"A. Valeeva, E. Gotlib, E. Yamaleeva","doi":"10.18323/2073-5073-2021-3-28-36","DOIUrl":"https://doi.org/10.18323/2073-5073-2021-3-28-36","url":null,"abstract":"The use of epoxy antifriction coatings can significantly reduce thermal stress in the friction zone and expand the coating working temperature interval while keeping high wear resistance. The paper considers the effect of non-activated and activated by surfactants silicate filler – rice husk ash on the physicochemical and mechanical properties of epoxy materials applied as antifriction coatings. All studied samples of rice husk ash, both initial and activated with surfactants, have an alkaline surface nature. The study identified that all cationic quaternary ammonium salts (QAS) reduce the pH of rice husk ash. At the same time, nonionic OXIPAV increases this indicator. Activation of the rice husk ash surface, both by the quaternary ammonium salts and aminosilanes, significantly reduces the porosity of this silicate. In this case, the average pore diameter does not change significantly, and their specific surface area decreases significantly, to a lesser extent, when activated by nonionic quaternary ammonium salts. The application of quaternary ammonium salts and aminosilanes in the amount of 33 % for activation of the surface of the investigated silicate filler reduces its modifying effect in epoxy compositions, regardless of the chemical structure of the surfactants used, which is not a typical effect. Therefore, the authors assumed that the suboptimal concentration of quaternary ammonium salts and aminosilanes was used. The study identified that the optimal concentration of 50 % alcohol solution of KATAPAV is 14.7–21 %. In this range of the QAS content, there is a significant increase in hardness (about 40 %), a slight decrease in wear (about 10 %), and a significant decrease in the coefficient of static friction (up to 2 times). At the same time, the authors observed an increase in adhesion to metal up to 3 times and bending strength up to 25 %. Thus, rice husk ash activated with an optimal amount of quaternary ammonium salts is an effective modifier of epoxy coatings, which improves their antifriction properties and increases wear resistance, hardness, strength, and adhesion characteristics.","PeriodicalId":23555,"journal":{"name":"Vektor nauki Tol'yattinskogo gosudarstvennogo universiteta","volume":"114 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88054313","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 : 2021-01-01DOI: 10.18323/2073-5073-2021-2-57-66
V. Sidorov, D. E. Sovetkin
The authors reviewed the research works on the effective power of direct and reverse polarity welding arcs with a non-consumable electrode in argon. The study shows that it is difficult to use the arc effective efficiency for effective power determination. It applies to the constricted arc more than to the free one. Based on data analysis for the effective power of polarities and the effective efficiency of a constricted arc burning toward the cooper heat flow calorimeter, the authors calculated the specific effective power of polarities and arc stresses. The maximum values are 23.2 W/A for the reverse polarity arc; and 14.2 W/A for the direct polarity arc. The study identified that the decrease in the specific effective power of polarities at the current increase within 100–150 A is well described by linear dependencies. With the current increase, there is a linear decrease in the direct polarity arc stress, while the reverse polarity arc stress remains constant. The spread of data for the specific effective power of polarities is about two times less than the spread for effective efficiency. Using a 2D mathematical model of the constricted arc column in a closed area, the authors calculated the power absorbed by plasma-forming argon and nozzle walls. As a result, the authors obtained the dependencies of the power transferred by argon on the nozzle channel length and the arc current. The specific effective power of argon flow for analyzed current densities and argon consumption shows poor dependence on the arc current and is equal to 5.5 W/A approximately. The power contribution of plasma-forming argon to the effective power of the constricted arc increases with the current increase.
{"title":"Effective power of a constricted welding arc with heteropolar current pulses","authors":"V. Sidorov, D. E. Sovetkin","doi":"10.18323/2073-5073-2021-2-57-66","DOIUrl":"https://doi.org/10.18323/2073-5073-2021-2-57-66","url":null,"abstract":"The authors reviewed the research works on the effective power of direct and reverse polarity welding arcs with a non-consumable electrode in argon. The study shows that it is difficult to use the arc effective efficiency for effective power determination. It applies to the constricted arc more than to the free one. Based on data analysis for the effective power of polarities and the effective efficiency of a constricted arc burning toward the cooper heat flow calorimeter, the authors calculated the specific effective power of polarities and arc stresses. The maximum values are 23.2 W/A for the reverse polarity arc; and 14.2 W/A for the direct polarity arc. The study identified that the decrease in the specific effective power of polarities at the current increase within 100–150 A is well described by linear dependencies. With the current increase, there is a linear decrease in the direct polarity arc stress, while the reverse polarity arc stress remains constant. The spread of data for the specific effective power of polarities is about two times less than the spread for effective efficiency. Using a 2D mathematical model of the constricted arc column in a closed area, the authors calculated the power absorbed by plasma-forming argon and nozzle walls. As a result, the authors obtained the dependencies of the power transferred by argon on the nozzle channel length and the arc current. The specific effective power of argon flow for analyzed current densities and argon consumption shows poor dependence on the arc current and is equal to 5.5 W/A approximately. The power contribution of plasma-forming argon to the effective power of the constricted arc increases with the current increase.","PeriodicalId":23555,"journal":{"name":"Vektor nauki Tol'yattinskogo gosudarstvennogo universiteta","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88345866","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 : 2021-01-01DOI: 10.18323/2073-5073-2021-1-55-62
A. Khazov, A. Unyanin
The study aimed to identify the relations between the sticking intensity and ultrasonic vibrations (UV) used for processing and evaluate the wheels’ performance when grinding ductile materials blank parts. The authors carried out the numerical simulation of local temperatures and the 3H3M3F steel workpiece temperature when grinding by ultrasonic activation. The study determined that the application of ultrasonic vibrations with the amplitude of 3 µm causes the decrease in local temperatures by 13…40 %, and in blank part temperature – up to 20 %. The calculation identified that the activation of ultrasonic vibrations with the amplitude of 3 µm causes the decrease in the glazing coefficient by 33 % for cutting grain and by 7 % for deforming grain. When increasing the longitudinal feed rate or the grinding depth, the glazing coefficient increases to a lesser degree when using the ultrasonic vibration than in the case without ultrasonic activation. The authors carried out the numerical simulation of local temperatures when scratching the 3H3M3F steel specimens by single abrasive grains with ultrasonic activation. The sticking deformation and the stresses resulted from this deformation and affecting the junction points of sticking with grains with and without ultrasonic vibrations application are calculated. The experimental research included the micro-cutting of specimens with single abrasive grains. The experiments identified that the abrasive grains wear out and glaze to a lesser degree when micro-cutting a workpiece with ultrasonic vibrations activation. The lowering of the intensity of sticking of the workpiece material particles to the abrasive grains due to the adhesion causes the decrease in the glazing coefficient when using ultrasonic activation. The study considered the possibility to enhance the efficiency of flat grinding through the use of the energy of ultrasonic vibrations applied to a blank part in the direction with the grinding wheel axis. A workpiece fixed in the device between the vibration transducer and the support is one of the components of a vibration system. The authors performed the experiment when grinding 3H3M3F and 12H18N10T steel workpieces with the wheel face. When grinding with ultrasonic vibrations, the grinding coefficient increases up to 70 %, and the redress life increases twice or thrice.
{"title":"The enhancement of cutting capacity of a grinding wheel when processing ductile steel blank parts by ultrasonic activation","authors":"A. Khazov, A. Unyanin","doi":"10.18323/2073-5073-2021-1-55-62","DOIUrl":"https://doi.org/10.18323/2073-5073-2021-1-55-62","url":null,"abstract":"The study aimed to identify the relations between the sticking intensity and ultrasonic vibrations (UV) used for processing and evaluate the wheels’ performance when grinding ductile materials blank parts. The authors carried out the numerical simulation of local temperatures and the 3H3M3F steel workpiece temperature when grinding by ultrasonic activation. The study determined that the application of ultrasonic vibrations with the amplitude of 3 µm causes the decrease in local temperatures by 13…40 %, and in blank part temperature – up to 20 %. The calculation identified that the activation of ultrasonic vibrations with the amplitude of 3 µm causes the decrease in the glazing coefficient by 33 % for cutting grain and by 7 % for deforming grain. When increasing the longitudinal feed rate or the grinding depth, the glazing coefficient increases to a lesser degree when using the ultrasonic vibration than in the case without ultrasonic activation. The authors carried out the numerical simulation of local temperatures when scratching the 3H3M3F steel specimens by single abrasive grains with ultrasonic activation. The sticking deformation and the stresses resulted from this deformation and affecting the junction points of sticking with grains with and without ultrasonic vibrations application are calculated. The experimental research included the micro-cutting of specimens with single abrasive grains. The experiments identified that the abrasive grains wear out and glaze to a lesser degree when micro-cutting a workpiece with ultrasonic vibrations activation. The lowering of the intensity of sticking of the workpiece material particles to the abrasive grains due to the adhesion causes the decrease in the glazing coefficient when using ultrasonic activation. The study considered the possibility to enhance the efficiency of flat grinding through the use of the energy of ultrasonic vibrations applied to a blank part in the direction with the grinding wheel axis. A workpiece fixed in the device between the vibration transducer and the support is one of the components of a vibration system. The authors performed the experiment when grinding 3H3M3F and 12H18N10T steel workpieces with the wheel face. When grinding with ultrasonic vibrations, the grinding coefficient increases up to 70 %, and the redress life increases twice or thrice.","PeriodicalId":23555,"journal":{"name":"Vektor nauki Tol'yattinskogo gosudarstvennogo universiteta","volume":"37 12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75860536","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 : 2021-01-01DOI: 10.18323/2073-5073-2021-2-35-46
E. Reshetnikova, P. Bochkarev
The relevance of the study is in the solution of an important problem – the improvement of the development of engineering procedures for producing goods within the production systems of conventional machine-building enterprises performing the transition to automation and intellectualization of their production cycle. To solve the above-stated task, the authors propose an innovative approach involving the development of efficient manufacturing procedures of producing goods by a multiproduct production system based on making effective project technology solutions. The suggested method of designing effective manufacturing procedures for producing goods by a multiproduct production system is implemented in the System of Computer-Aided Planning of Manufacturing Procedures developed by the authors. The System of Computer-Aided Planning of Manufacturing Procedures is a modern tool for automation of engineering process preparation corresponding to the relevant concept of production digitalization. The set of monitoring and measuring procedures developed by the authors and promoting the improvement of the System of Computer-Aided Planning of Manufacturing Procedures is aimed at the modernization of machining productions with the traditional production cycle and supporting their digital transformation process. The set of monitoring and measuring procedures performs the automated designing of efficient individual manufacturing procedures within a small-series production based on the information about actual dimensional parameters of the part blank surfaces at the initial stage of creation of a manufacturing procedure and based on the integration into the manufacturing procedure structure of an efficient set of monitoring and measuring tools formed on the base of the complex of monitoring and measuring procedures to evaluate the prescribed accuracy of part production. The paper presents methodological and algorithmic provisions of implementing complex of monitoring and measuring procedures, which include the development of the technique of the parts’ coordinate metrology serving as a structural element of an efficient manufacturing procedure and the algorithm of formation of the efficient set of monitoring and measuring tools when designing efficient manufacturing procedure.
{"title":"Innovative approach to the development of manufacturing procedures of producing goods in a multiproduct manufacture","authors":"E. Reshetnikova, P. Bochkarev","doi":"10.18323/2073-5073-2021-2-35-46","DOIUrl":"https://doi.org/10.18323/2073-5073-2021-2-35-46","url":null,"abstract":"The relevance of the study is in the solution of an important problem – the improvement of the development of engineering procedures for producing goods within the production systems of conventional machine-building enterprises performing the transition to automation and intellectualization of their production cycle. To solve the above-stated task, the authors propose an innovative approach involving the development of efficient manufacturing procedures of producing goods by a multiproduct production system based on making effective project technology solutions. The suggested method of designing effective manufacturing procedures for producing goods by a multiproduct production system is implemented in the System of Computer-Aided Planning of Manufacturing Procedures developed by the authors. The System of Computer-Aided Planning of Manufacturing Procedures is a modern tool for automation of engineering process preparation corresponding to the relevant concept of production digitalization. The set of monitoring and measuring procedures developed by the authors and promoting the improvement of the System of Computer-Aided Planning of Manufacturing Procedures is aimed at the modernization of machining productions with the traditional production cycle and supporting their digital transformation process. The set of monitoring and measuring procedures performs the automated designing of efficient individual manufacturing procedures within a small-series production based on the information about actual dimensional parameters of the part blank surfaces at the initial stage of creation of a manufacturing procedure and based on the integration into the manufacturing procedure structure of an efficient set of monitoring and measuring tools formed on the base of the complex of monitoring and measuring procedures to evaluate the prescribed accuracy of part production. The paper presents methodological and algorithmic provisions of implementing complex of monitoring and measuring procedures, which include the development of the technique of the parts’ coordinate metrology serving as a structural element of an efficient manufacturing procedure and the algorithm of formation of the efficient set of monitoring and measuring tools when designing efficient manufacturing procedure.","PeriodicalId":23555,"journal":{"name":"Vektor nauki Tol'yattinskogo gosudarstvennogo universiteta","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77644450","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 : 2021-01-01DOI: 10.18323/2073-5073-2021-3-7-18
A. Atamashkin, E. Priymak
At modern mechanical facilities, the friction-welded joints are getting widespread as the most advanced production technique characterized by high efficiency, processability, cost-effectiveness, and safety. Moreover, it allows producing high-quality joints of a large number of different analogous and opposite metals and alloys. Despite all these advantages, one should consider that metal, in the process of welded joint formation, suffers a local thermo-deformational effect, which causes the gradient nature of the structure and residual strains of a welded joint. These factors directly influence the structure’s working ability and durability under fatigue loads, which are the most common cause for parts failure. The paper contains the assessment of the post-weld tempering influence on the cyclic life of welded joints of 32G2 and 40HN steels produced using the rotational friction welding technique. The authors tested laboratory specimens with welded joints under the high-cycle fatigue using the simulation machine with the two-point fastening of a revolving specimen under the action of even twisting moment. The study involved the statistical processing of the obtained results of cyclic life. Based on the metallographic analysis, the authors identified the weak points in welded points where the fatigue cracks initiation and progress occurred in the initial state and after tempering. The paper presents the fractographs illustrating the fracture mechanism of specimens under the study. The authors identified the influence of different tempering temperature modes on the cyclic life of the studied welded joints and the nature of their fracture. The study shows that tempering at the temperature over 400 °C promotes fracture acceleration under the effect of fatigue loads due to the development of return and polygonization processes in the vulnerable area of the thermomechanical action zone.
{"title":"THE INFLUENCE OF POSTWELD TEMPERING ON MECHANICAL BEHAVIOR OF FRICTION WELDED JOINTS OF 32G2 AND 40HN STEELS UNDER HIGH-CYCLE FATIGUE","authors":"A. Atamashkin, E. Priymak","doi":"10.18323/2073-5073-2021-3-7-18","DOIUrl":"https://doi.org/10.18323/2073-5073-2021-3-7-18","url":null,"abstract":"At modern mechanical facilities, the friction-welded joints are getting widespread as the most advanced production technique characterized by high efficiency, processability, cost-effectiveness, and safety. Moreover, it allows producing high-quality joints of a large number of different analogous and opposite metals and alloys. Despite all these advantages, one should consider that metal, in the process of welded joint formation, suffers a local thermo-deformational effect, which causes the gradient nature of the structure and residual strains of a welded joint. These factors directly influence the structure’s working ability and durability under fatigue loads, which are the most common cause for parts failure. The paper contains the assessment of the post-weld tempering influence on the cyclic life of welded joints of 32G2 and 40HN steels produced using the rotational friction welding technique. The authors tested laboratory specimens with welded joints under the high-cycle fatigue using the simulation machine with the two-point fastening of a revolving specimen under the action of even twisting moment. The study involved the statistical processing of the obtained results of cyclic life. Based on the metallographic analysis, the authors identified the weak points in welded points where the fatigue cracks initiation and progress occurred in the initial state and after tempering. The paper presents the fractographs illustrating the fracture mechanism of specimens under the study. The authors identified the influence of different tempering temperature modes on the cyclic life of the studied welded joints and the nature of their fracture. The study shows that tempering at the temperature over 400 °C promotes fracture acceleration under the effect of fatigue loads due to the development of return and polygonization processes in the vulnerable area of the thermomechanical action zone.","PeriodicalId":23555,"journal":{"name":"Vektor nauki Tol'yattinskogo gosudarstvennogo universiteta","volume":"395 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79695511","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 : 2021-01-01DOI: 10.18323/2073-5073-2021-2-26-34
D. Rastorguev, K. Semenov
The paper considers the issues of ensuring the uniformity of strain of axisymmetric long-dimensional samples during thermal force processing (TFP), which is the simultaneous application of force and temperature effects for comprehensive improvement of geometric characteristics and physical and mechanical parameters of the workpiece material. This technology is used at various stages of technological processes of parts manufacturing, but its main task is to ensure the axis straightness and the specified distribution of residual technological stresses at the procuring stage. The disadvantage of TFP is that the axial deformation proceeds nonuniformly along the workpiece axis. The core process parameter is the deformation, the control of which is a key factor ensuring the TFP efficiency. The authors studied the plastic strain distribution over the sections of long-length workpieces with different deformation degrees. The study involved the assessment of strain uniformity over the workpiece sections, taking into account the stage of the stress-strain relation at the end of the loading cycle. Based on the concepts of plastic deformation as an auto-wave process, the authors selected the range of technological modes corresponding to the most uniform strain distribution along the workpiece axis with complete processing of the entire workpiece volume. This range corresponds to the stage of parabolic hardening of the plastic flow curve with the formation of the maximum number of stationary zones of localized plasticity. Rheological modeling allows identifying the control points that specify the boundaries of the plastic flow curve stages at various loading parameters, including temperature. To improve the reliability of determining the actual deformation under production conditions, the authors proposed modernizing the TFP process monitoring method by fixing the deformation on a limited workpiece section using the optical technique. The statistical analysis of the strain distribution over the sections for the samples confirms the correctness of this approach. The application of the proposed control method will ensure the most uniform distribution of plastic deformation due to the reliable enter of the workpiece deformation to the range of strain values corresponding to the stage of parabolic hardening of the plastic flow curve.
{"title":"Special aspects of strain localization during thermal power processing","authors":"D. Rastorguev, K. Semenov","doi":"10.18323/2073-5073-2021-2-26-34","DOIUrl":"https://doi.org/10.18323/2073-5073-2021-2-26-34","url":null,"abstract":"The paper considers the issues of ensuring the uniformity of strain of axisymmetric long-dimensional samples during thermal force processing (TFP), which is the simultaneous application of force and temperature effects for comprehensive improvement of geometric characteristics and physical and mechanical parameters of the workpiece material. This technology is used at various stages of technological processes of parts manufacturing, but its main task is to ensure the axis straightness and the specified distribution of residual technological stresses at the procuring stage. The disadvantage of TFP is that the axial deformation proceeds nonuniformly along the workpiece axis. The core process parameter is the deformation, the control of which is a key factor ensuring the TFP efficiency. The authors studied the plastic strain distribution over the sections of long-length workpieces with different deformation degrees. The study involved the assessment of strain uniformity over the workpiece sections, taking into account the stage of the stress-strain relation at the end of the loading cycle. Based on the concepts of plastic deformation as an auto-wave process, the authors selected the range of technological modes corresponding to the most uniform strain distribution along the workpiece axis with complete processing of the entire workpiece volume. This range corresponds to the stage of parabolic hardening of the plastic flow curve with the formation of the maximum number of stationary zones of localized plasticity. Rheological modeling allows identifying the control points that specify the boundaries of the plastic flow curve stages at various loading parameters, including temperature. To improve the reliability of determining the actual deformation under production conditions, the authors proposed modernizing the TFP process monitoring method by fixing the deformation on a limited workpiece section using the optical technique. The statistical analysis of the strain distribution over the sections for the samples confirms the correctness of this approach. The application of the proposed control method will ensure the most uniform distribution of plastic deformation due to the reliable enter of the workpiece deformation to the range of strain values corresponding to the stage of parabolic hardening of the plastic flow curve.","PeriodicalId":23555,"journal":{"name":"Vektor nauki Tol'yattinskogo gosudarstvennogo universiteta","volume":"24 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73403928","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：