Pub Date : 2023-06-13DOI: 10.17212/1994-6309-2023-25.2-17-31
I. Berezin, A. Zalazinsky, D. Kryuchkov
Introduction. The use of equal-channel angular pressing (ECAP) of metal powder makes it possible to obtain practically non-porous blanks with high hardness, with a high level of accumulated deformation and with the formation of an ultra-fine-grained structure. A relevant issue for the study of the semi-continuous ECAP process remains a reliable assessment of the energy-power parameters of the process and the prediction of the porosity of compressed materials. This, in turn, is due to the need to develop sufficiently accurate, reliable and simple mathematical models for practical application. The purpose of the work is to develop an analytical model of the process of equal-channel angular pressing of porous material. Powdered screening of spongy titanium of the TG-100 brand was selected as a model of the material for the study. The object of the study is the process of semi-continuous equal-channel angular pressing of axisymmetric porous briquette of titanium sponge in the channel of the mold. It is assumed that the ECAP uses a punch to create back pressure. For the solution, a process scheme, a statically permissible load scheme on a layer of intense deformation and a kinematically permissible flow scheme of a plastically compressible medium in a layer are determined. A system of equations is constructed in accordance with the accepted schemes. The equation power balance is applied. The analytical equation is solved by the method of successive approximations. Finite element simulation of the porous titanium ECAP process was carried out at the angles of intersection of the mold channels at 45°, 50°, 55° and 60°. Results and Discussion. The porosity of the blank is determined at different stages of the ECAP process. A diagram of the change in pressure on the punch using the analytical solution and finite element simulation is obtained. It is revealed that the results of the analytical solution are consistent with the data of the finite element simulation. The highest stress level occurs in the process of equal-channel angular pressing at α = 45°, however, the distribution of relative density over the cross section is most uniform. The maximum value of the pressure on the working punch decreases with an increase in the angle α. Rational technological parameters of pressing porous blanks should provide the maximum permissible pressure on the deforming tool. From this condition, in each specific ECAP process, it is possible to determine the optimal angle value from the analytical solution.
{"title":"Analytical model of equal-channel angular pressing of titanium sponge","authors":"I. Berezin, A. Zalazinsky, D. Kryuchkov","doi":"10.17212/1994-6309-2023-25.2-17-31","DOIUrl":"https://doi.org/10.17212/1994-6309-2023-25.2-17-31","url":null,"abstract":"Introduction. The use of equal-channel angular pressing (ECAP) of metal powder makes it possible to obtain practically non-porous blanks with high hardness, with a high level of accumulated deformation and with the formation of an ultra-fine-grained structure. A relevant issue for the study of the semi-continuous ECAP process remains a reliable assessment of the energy-power parameters of the process and the prediction of the porosity of compressed materials. This, in turn, is due to the need to develop sufficiently accurate, reliable and simple mathematical models for practical application. The purpose of the work is to develop an analytical model of the process of equal-channel angular pressing of porous material. Powdered screening of spongy titanium of the TG-100 brand was selected as a model of the material for the study. The object of the study is the process of semi-continuous equal-channel angular pressing of axisymmetric porous briquette of titanium sponge in the channel of the mold. It is assumed that the ECAP uses a punch to create back pressure. For the solution, a process scheme, a statically permissible load scheme on a layer of intense deformation and a kinematically permissible flow scheme of a plastically compressible medium in a layer are determined. A system of equations is constructed in accordance with the accepted schemes. The equation power balance is applied. The analytical equation is solved by the method of successive approximations. Finite element simulation of the porous titanium ECAP process was carried out at the angles of intersection of the mold channels at 45°, 50°, 55° and 60°. Results and Discussion. The porosity of the blank is determined at different stages of the ECAP process. A diagram of the change in pressure on the punch using the analytical solution and finite element simulation is obtained. It is revealed that the results of the analytical solution are consistent with the data of the finite element simulation. The highest stress level occurs in the process of equal-channel angular pressing at α = 45°, however, the distribution of relative density over the cross section is most uniform. The maximum value of the pressure on the working punch decreases with an increase in the angle α. Rational technological parameters of pressing porous blanks should provide the maximum permissible pressure on the deforming tool. From this condition, in each specific ECAP process, it is possible to determine the optimal angle value from the analytical solution.","PeriodicalId":42889,"journal":{"name":"Obrabotka Metallov-Metal Working and Material Science","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2023-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45014419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-13DOI: 10.17212/1994-6309-2023-25.2-32-44
V. Kuts, Sergey Сhevychelov
Introduction. The paper discusses the methods of processing large parts having curved convex surfaces with a rectilinear guide on multi-coordinate CNC machining centers using the touch method with a discrete motion of the tool feed along the profile of the part. It is shown that the main disadvantages of this method are lower productivity, which is due to the presence of discrete tool motions between cycles of its translation mode, where the value of discrete tool motion for a given processing accuracy depends on the curvature of the surface being processed. To improve processing performance, it is proposed to use prefabricated disc cutters equipped with replaceable polyhedral inserts (RPI) with rectilinear cutting edges. Its installation in the cutter body with non-zero angles of inclination of the main cutting edge, in combination with an additional rotation of the cutter, during processing, along the direction of the translational feed movement, allows you to obtain a concave surface and ensure a tighter fit of the producing surface of the tool and the machined surface of the part. The aim of the work is to reduce the error of approximation of the profile when it is processed using the touch method with discrete motion of prefabricated disc cutters along the profile and, consequently, to ensure workpiece the possibility of increasing the step of tool movement along the profile being formed to improve processing performance. Research methods: geometrical theory of designing metal-cutting tools. Results and discussion. The regularities established in the work made it possible to create a method for determining the angle of inclination of the main cutting edge of the RPI milling cutter and the angles of rotation of the milling cutter along the direction of translational feed movement during line-by-line processing of extended sections of parts with a curved profile on multi-coordinate CNC machines by turning the milling cutter to ensure the best fit of its producing surface to the surface being processed at the point of its contact, to reduce the approximation error processed profile and improve processing performance, due to the possibility of increasing the tool movement step.
{"title":"Theoretical study of the curvature of the treated surface during oblique milling with prefabricated milling cutters","authors":"V. Kuts, Sergey Сhevychelov","doi":"10.17212/1994-6309-2023-25.2-32-44","DOIUrl":"https://doi.org/10.17212/1994-6309-2023-25.2-32-44","url":null,"abstract":"Introduction. The paper discusses the methods of processing large parts having curved convex surfaces with a rectilinear guide on multi-coordinate CNC machining centers using the touch method with a discrete motion of the tool feed along the profile of the part. It is shown that the main disadvantages of this method are lower productivity, which is due to the presence of discrete tool motions between cycles of its translation mode, where the value of discrete tool motion for a given processing accuracy depends on the curvature of the surface being processed. To improve processing performance, it is proposed to use prefabricated disc cutters equipped with replaceable polyhedral inserts (RPI) with rectilinear cutting edges. Its installation in the cutter body with non-zero angles of inclination of the main cutting edge, in combination with an additional rotation of the cutter, during processing, along the direction of the translational feed movement, allows you to obtain a concave surface and ensure a tighter fit of the producing surface of the tool and the machined surface of the part. The aim of the work is to reduce the error of approximation of the profile when it is processed using the touch method with discrete motion of prefabricated disc cutters along the profile and, consequently, to ensure workpiece the possibility of increasing the step of tool movement along the profile being formed to improve processing performance. Research methods: geometrical theory of designing metal-cutting tools. Results and discussion. The regularities established in the work made it possible to create a method for determining the angle of inclination of the main cutting edge of the RPI milling cutter and the angles of rotation of the milling cutter along the direction of translational feed movement during line-by-line processing of extended sections of parts with a curved profile on multi-coordinate CNC machines by turning the milling cutter to ensure the best fit of its producing surface to the surface being processed at the point of its contact, to reduce the approximation error processed profile and improve processing performance, due to the possibility of increasing the tool movement step.","PeriodicalId":42889,"journal":{"name":"Obrabotka Metallov-Metal Working and Material Science","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2023-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46149772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-13DOI: 10.17212/1994-6309-2023-25.2-68-80
A. Vorontsov, A. Filippov, N. Shamarin, E. Moskvichev, O. Novitskaya, Evgenii Knyazhev, Yu. I. Denisova, A. Leonov, V. Denisov
Introduction. Advanced hard coatings combine different properties such as high hardness, wear resistance, corrosive resistance. At present, layer-by-layer deposited zirconium and chromium nitrides are promising hard coating materials. Currently, the multilayer coating process is not sufficiently described in the literature to understand all the processes involved. The problem is the complexity of depositing thick layers of multilayer, multicomponent coatings with different physical characteristics of the coating components. First and foremost this concerns the coefficient of linear thermal expansion (CTE). Since the coating and operating processes consist in heating, coating components with different CTE will be susceptible to cracking, further failure and product failure over time. The purpose of work is in-situ study of multilayer ZrN/CrN coatings by X-ray analysis using synchrotron radiation and qualitative microstress behavior of multilayer coatings formed by plasma-assisted vacuum-arc method on substrate of alloy VK8 (92% WC–8% Co) under heating up to 750°С. Research methodology. Samples of coatings made of chromium and zirconium nitrides deposited on a substrate of the hard alloy VK8 are investigated. The basic method is the X-ray analysis using synchrotron radiation. We used the most common techniques to study the characteristics of multilayered coatings such as the coefficient of linear thermal expansion and the qualitative measurement of microstresses. Results and discussion. The result is the ability to determine changes in the characteristics of multilayer coatings during heating, such as changes in the crystal lattice parameter of each of the coating components separately, the possibility to determine the coefficient of linear thermal expansion of the coating components and the qualitative measurement of microstresses, as well as providing the opportunity, based on the analysis, to form recommendations for further application of the technology of applying multilayer coatings with given characteristics.
{"title":"In-situ analysis of ZrN/CrN multilayer coatings under heating","authors":"A. Vorontsov, A. Filippov, N. Shamarin, E. Moskvichev, O. Novitskaya, Evgenii Knyazhev, Yu. I. Denisova, A. Leonov, V. Denisov","doi":"10.17212/1994-6309-2023-25.2-68-80","DOIUrl":"https://doi.org/10.17212/1994-6309-2023-25.2-68-80","url":null,"abstract":"Introduction. Advanced hard coatings combine different properties such as high hardness, wear resistance, corrosive resistance. At present, layer-by-layer deposited zirconium and chromium nitrides are promising hard coating materials. Currently, the multilayer coating process is not sufficiently described in the literature to understand all the processes involved. The problem is the complexity of depositing thick layers of multilayer, multicomponent coatings with different physical characteristics of the coating components. First and foremost this concerns the coefficient of linear thermal expansion (CTE). Since the coating and operating processes consist in heating, coating components with different CTE will be susceptible to cracking, further failure and product failure over time. The purpose of work is in-situ study of multilayer ZrN/CrN coatings by X-ray analysis using synchrotron radiation and qualitative microstress behavior of multilayer coatings formed by plasma-assisted vacuum-arc method on substrate of alloy VK8 (92% WC–8% Co) under heating up to 750°С. Research methodology. Samples of coatings made of chromium and zirconium nitrides deposited on a substrate of the hard alloy VK8 are investigated. The basic method is the X-ray analysis using synchrotron radiation. We used the most common techniques to study the characteristics of multilayered coatings such as the coefficient of linear thermal expansion and the qualitative measurement of microstresses. Results and discussion. The result is the ability to determine changes in the characteristics of multilayer coatings during heating, such as changes in the crystal lattice parameter of each of the coating components separately, the possibility to determine the coefficient of linear thermal expansion of the coating components and the qualitative measurement of microstresses, as well as providing the opportunity, based on the analysis, to form recommendations for further application of the technology of applying multilayer coatings with given characteristics.","PeriodicalId":42889,"journal":{"name":"Obrabotka Metallov-Metal Working and Material Science","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2023-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42399407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-13DOI: 10.17212/1994-6309-2023-25.2-104-116
Y. Émurlaeva, D. Lazurenko, Z. Bataeva, I. Petrov, G. Dovzhenko, Lubov Makogon, M. Khomyakov, K. Emurlaev, I. Bataev
Introduction. Vacancies are among the crystal lattice defects that have a significant effect on the structural transformations processes during thermal, chemical-thermal, thermomechanical, and other types of alloys treatment. The vacancy formation energy is one of the most important parameters used to describe diffusion processes. An effective approach to its definition is based on the use of the density functional theory (DFT). The main advantage of this method is to carry out computations without any parameters defined empirically. The purpose of the work is to estimate vacancy formation energy of BCC-, FCC- and HCP-metals widely used in mechanical engineering and to compare these findings obtained using various exchange-correlation functionals (GGA and meta-GGA). Computation procedure. The computations were carried out using the projector-augmented wave method using the GPAW code and the atomic simulation environment (ASE). The Perdew-Burke-Ernzerhof, MGGAC and rMGGAC functionals were used. The wave functions were described by plane waves within simulations. Vacancies formation energy was evaluated using supercells approach with a size 3 × 3 × 3. Computations were carried out for BCC-metals (Li, Na, K, V, Cr, Fe, Rb, Nb, Mo, Cs, Ta, W), FCC-metals (Al, Ni, Cu, Rh, Pd, Ag, Ir, Pt, Au, Pb, Co) and HCP-metals (Be, Ti, Zr, Mg, Sc, Zn, Y, Ru, Cd, Hf, Os, Co, Re). Results and discussion. A comparison of the defined vacancy formation energies indicates the validity of the following ratio of values: . The values obtained using the open source GPAW code are characterized by the same patterns as for widely spread commercially distributed program VASP. It was revealed that the use of the PBE and MGGAC functionals leads to a slight deviation relative to the experimentally determined vacancies formation energy in contrast to the computations using rMGGAC.
{"title":"Evaluation of vacancy formation energy for BCC-, FCC-, and HCP-metals using density functional theory","authors":"Y. Émurlaeva, D. Lazurenko, Z. Bataeva, I. Petrov, G. Dovzhenko, Lubov Makogon, M. Khomyakov, K. Emurlaev, I. Bataev","doi":"10.17212/1994-6309-2023-25.2-104-116","DOIUrl":"https://doi.org/10.17212/1994-6309-2023-25.2-104-116","url":null,"abstract":"Introduction. Vacancies are among the crystal lattice defects that have a significant effect on the structural transformations processes during thermal, chemical-thermal, thermomechanical, and other types of alloys treatment. The vacancy formation energy is one of the most important parameters used to describe diffusion processes. An effective approach to its definition is based on the use of the density functional theory (DFT). The main advantage of this method is to carry out computations without any parameters defined empirically. The purpose of the work is to estimate vacancy formation energy of BCC-, FCC- and HCP-metals widely used in mechanical engineering and to compare these findings obtained using various exchange-correlation functionals (GGA and meta-GGA). Computation procedure. The computations were carried out using the projector-augmented wave method using the GPAW code and the atomic simulation environment (ASE). The Perdew-Burke-Ernzerhof, MGGAC and rMGGAC functionals were used. The wave functions were described by plane waves within simulations. Vacancies formation energy was evaluated using supercells approach with a size 3 × 3 × 3. Computations were carried out for BCC-metals (Li, Na, K, V, Cr, Fe, Rb, Nb, Mo, Cs, Ta, W), FCC-metals (Al, Ni, Cu, Rh, Pd, Ag, Ir, Pt, Au, Pb, Co) and HCP-metals (Be, Ti, Zr, Mg, Sc, Zn, Y, Ru, Cd, Hf, Os, Co, Re). Results and discussion. A comparison of the defined vacancy formation energies indicates the validity of the following ratio of values: . The values obtained using the open source GPAW code are characterized by the same patterns as for widely spread commercially distributed program VASP. It was revealed that the use of the PBE and MGGAC functionals leads to a slight deviation relative to the experimentally determined vacancies formation energy in contrast to the computations using rMGGAC.","PeriodicalId":42889,"journal":{"name":"Obrabotka Metallov-Metal Working and Material Science","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2023-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49444796","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-13DOI: 10.17212/1994-6309-2023-25.2-6-16
A. Kisel’, V. Churankin
Introduction. The processes occurring in the cutting zone contribute to the rapid wear of the cutting tool and a decrease in the quality of the workpiece. It is possible to reduce the impact of negative factors during metal cutting through a rational choice of coolant. The aim of the work is to develop a methodology for the accelerated assessment of the coolant lubricating properties. Methods. Experimental studies of the lubricating effect of seven different grades of coolant, during friction of a T15K6 (15% TiC–79% WC–6% Co) hard alloy pad and a rotating roller made of carbon structural Steel 45 (0.45% C) are presented. As a parameter of coolant efficiency in terms of lubricating effect, paper proposes an efficiency coefficient Kc, which is equal to the ratio between the friction coefficient that occurs when using coolant and the friction coefficient during friction without coolant. The lower the coefficient Kc, the more effective this coolant is in terms of lubricating effect. Results. Empirical dependences of the coefficient Kc on the coolant density ρ and the limiting wetting angle Θ (Kc = f(ρ;Θ)) are established. Since the low significance of the parameter ρ is established, the formula for the dependence of the Kc only on the limiting wetting angle Θ (Kc = f(Θ)) is established in the work. It is established that the dependence formula (Kc = f(Θ) provides the highest accuracy of calculations. Discussion. After evaluating the research results presented in this paper, the following conclusions are made: 1) the paper establishes the influence of the coolant density and the limiting wetting angle on the coolant efficiency coefficient for the lubricating effect determined for the friction between a roller made of Steel 45 and a pad made of T15K6 alloy: Kc = f(ρ;Θ) and Kc = f(Θ); 2) the greatest accuracy of calculations from 2.75 to 15% is provided by the formula for the dependence Kc = f(Θ); 3) the dependence Kc = f(Θ)is proposed to be used for the method for the accelerated assessment of the coolant lubricating properties during friction of a pad made of T15K6 alloy and a rotating roller made of Steel 45. The proposed method consists in measuring the limiting wetting angle of a coolant drop on the surface of the workpiece and calculating the derived empirical dependence of the coolant efficiency coefficient on the lubricating effect.
{"title":"Predicting the coolant lubricating properties based on its density and wetting effect","authors":"A. Kisel’, V. Churankin","doi":"10.17212/1994-6309-2023-25.2-6-16","DOIUrl":"https://doi.org/10.17212/1994-6309-2023-25.2-6-16","url":null,"abstract":"Introduction. The processes occurring in the cutting zone contribute to the rapid wear of the cutting tool and a decrease in the quality of the workpiece. It is possible to reduce the impact of negative factors during metal cutting through a rational choice of coolant. The aim of the work is to develop a methodology for the accelerated assessment of the coolant lubricating properties. Methods. Experimental studies of the lubricating effect of seven different grades of coolant, during friction of a T15K6 (15% TiC–79% WC–6% Co) hard alloy pad and a rotating roller made of carbon structural Steel 45 (0.45% C) are presented. As a parameter of coolant efficiency in terms of lubricating effect, paper proposes an efficiency coefficient Kc, which is equal to the ratio between the friction coefficient that occurs when using coolant and the friction coefficient during friction without coolant. The lower the coefficient Kc, the more effective this coolant is in terms of lubricating effect. Results. Empirical dependences of the coefficient Kc on the coolant density ρ and the limiting wetting angle Θ (Kc = f(ρ;Θ)) are established. Since the low significance of the parameter ρ is established, the formula for the dependence of the Kc only on the limiting wetting angle Θ (Kc = f(Θ)) is established in the work. It is established that the dependence formula (Kc = f(Θ) provides the highest accuracy of calculations. Discussion. After evaluating the research results presented in this paper, the following conclusions are made: 1) the paper establishes the influence of the coolant density and the limiting wetting angle on the coolant efficiency coefficient for the lubricating effect determined for the friction between a roller made of Steel 45 and a pad made of T15K6 alloy: Kc = f(ρ;Θ) and Kc = f(Θ); 2) the greatest accuracy of calculations from 2.75 to 15% is provided by the formula for the dependence Kc = f(Θ); 3) the dependence Kc = f(Θ)is proposed to be used for the method for the accelerated assessment of the coolant lubricating properties during friction of a pad made of T15K6 alloy and a rotating roller made of Steel 45. The proposed method consists in measuring the limiting wetting angle of a coolant drop on the surface of the workpiece and calculating the derived empirical dependence of the coolant efficiency coefficient on the lubricating effect.","PeriodicalId":42889,"journal":{"name":"Obrabotka Metallov-Metal Working and Material Science","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2023-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42121526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-13DOI: 10.17212/1994-6309-2023-25.2-81-92
E. Kornienko, I. Gulyaev, V. Kuzmin, A. Tambovtsev, Pavel Tyryshkin
Introduction. Carbon steel is often used for the manufacture of various machine parts, but its operation in aggressive conditions (operation of steel parts under conditions of wear, high temperatures and aggressive corrosive environments) contributes to an extreme decline in properties, up to failure. To solve this problem the modification of the working surfaces of steel parts can be used. It increases its wear resistance, corrosion resistance, and service life. Metal-ceramic coatings based on WC are often used to improve the hardness, wear resistance and corrosion resistance of steel parts. The work purpose is to study the effect of high velocity atmospheric plasma spraying (HV-APS) modes on the structure, phase composition and properties of WC-Co coatings. Materials and methods. 86% WC-10% Co-4% Cr coatings were deposited on a mild steel substrate with help of the HV-APS method. The structure and phase composition of the coatings were analyzed using optical microscopy, scanning electron microscopy, and X-ray phase analysis. In addition, the results of measurements of porosity, microhardness, wear resistance, as well as a qualitative assessment of the adhesion are shown in this paper. Results and discussion. It is shown that all coatings are characterized by high density, absence of cracks and oxide films. Using the SEM and XRD methods, it is found that the coatings contain WC and W2C particles uniformly distributed in the metal matrix. The matrix is an amorphous or nanocrystalline supersaturated Co(W,C) solid solution. The maximum amount of carbides (49%) is observed in coatings obtained by deposition from a distance of 170 mm, arc current — 140 A; the minimum (25%) is observed in coatings obtained by deposition from a distance of 250 mm, arc current — 200 A. The coatings with the maximum amount of carbides have the maximum values of microhardness (1,284 HV0.1) and wear resistance. It is established that all coatings are characterized by high adhesion.
{"title":"Structure and properties of WC-10Co4Cr coatings obtained with high velocity atmospheric plasma spraying","authors":"E. Kornienko, I. Gulyaev, V. Kuzmin, A. Tambovtsev, Pavel Tyryshkin","doi":"10.17212/1994-6309-2023-25.2-81-92","DOIUrl":"https://doi.org/10.17212/1994-6309-2023-25.2-81-92","url":null,"abstract":"Introduction. Carbon steel is often used for the manufacture of various machine parts, but its operation in aggressive conditions (operation of steel parts under conditions of wear, high temperatures and aggressive corrosive environments) contributes to an extreme decline in properties, up to failure. To solve this problem the modification of the working surfaces of steel parts can be used. It increases its wear resistance, corrosion resistance, and service life. Metal-ceramic coatings based on WC are often used to improve the hardness, wear resistance and corrosion resistance of steel parts. The work purpose is to study the effect of high velocity atmospheric plasma spraying (HV-APS) modes on the structure, phase composition and properties of WC-Co coatings. Materials and methods. 86% WC-10% Co-4% Cr coatings were deposited on a mild steel substrate with help of the HV-APS method. The structure and phase composition of the coatings were analyzed using optical microscopy, scanning electron microscopy, and X-ray phase analysis. In addition, the results of measurements of porosity, microhardness, wear resistance, as well as a qualitative assessment of the adhesion are shown in this paper. Results and discussion. It is shown that all coatings are characterized by high density, absence of cracks and oxide films. Using the SEM and XRD methods, it is found that the coatings contain WC and W2C particles uniformly distributed in the metal matrix. The matrix is an amorphous or nanocrystalline supersaturated Co(W,C) solid solution. The maximum amount of carbides (49%) is observed in coatings obtained by deposition from a distance of 170 mm, arc current — 140 A; the minimum (25%) is observed in coatings obtained by deposition from a distance of 250 mm, arc current — 200 A. The coatings with the maximum amount of carbides have the maximum values of microhardness (1,284 HV0.1) and wear resistance. It is established that all coatings are characterized by high adhesion.","PeriodicalId":42889,"journal":{"name":"Obrabotka Metallov-Metal Working and Material Science","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2023-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41436286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-13DOI: 10.17212/1994-6309-2023-25.2-45-67
V Yu Skeeba, Egor Zverev, P. Skeeba, A. Chernikov, Andrey Popkov
Introduction. Improving the competitiveness of manufactured products is impossible without achieving high rates of resource and energy saving, while providing modern machine tools with the proper level of production flexibility in combination with guaranteed high values of processing productivity and the required level of parts manufacturing quality. Insufficient or excess capacity of technological equipment leads to a decrease in its economic efficiency, an increase in capital costs and, as a result, an increase in the cost of production. In the machine tool industry, which is a strategically significant and basic industry for the modernization of mechanical engineering, there is a special interest in the development of a new type of technological equipment that makes it possible to implement methods for modifying the surface layers of parts by processing it with concentrated energy sources. The combination of two processing technologies (mechanical and surface-thermal operations) in the conditions of integrated equipment makes it possible to level the shortcomings of monotechnologies and obtain new effects that are unattainable when using technologies separately. Ensuring an optimal level of quality — one of the unconditional requirements of a market economy — is a priority when developing the overall concept of technological equipment. Thus, it should be noted that the required and specific set of consumer properties are laid down during the design. And, therefore, the problem of quality optimization belongs to the field of forecasting and should be comprehensively addressed at the initial stage of developing the concept of technological equipment. The purpose of this research is to rationally choose the objects of modernization when carrying out work related to retrofitting a standard machine tool system with an additional concentrated energy source. Methods: Theoretical studies of the possible structural composition and layout of hybrid equipment during the integration of mechanical and surface-thermal processes were carried out taking into account the main provisions of structural synthesis and components of metal-cutting systems. During the research, issues related to the main provisions of system analysis, the geometric theory of surface formation, the design of metal-cutting equipment, methods of mathematical and computer modeling were raised. Results and discussion. Theoretical studies is found that currently, most of the parameter-oriented (dimension) series of general-purpose metal-cutting machines, built according to the law of geometric progression with a constant denominator, are the cause of multiple duplication of individual size ranges on machines of the same series. This gives grounds to talk about an unreasonable increase in the number of its members and, as a result, to an increase in the cost of designing, manufacturing and operating equipment. The authors adhere to the point of view that in order to ensure maximum efficienc
{"title":"Hybrid technological equipment: on the issue of a rational choice of objects of modernization when carrying out work related to retrofitting a standard machine tool system with an additional concentrated energy source","authors":"V Yu Skeeba, Egor Zverev, P. Skeeba, A. Chernikov, Andrey Popkov","doi":"10.17212/1994-6309-2023-25.2-45-67","DOIUrl":"https://doi.org/10.17212/1994-6309-2023-25.2-45-67","url":null,"abstract":"Introduction. Improving the competitiveness of manufactured products is impossible without achieving high rates of resource and energy saving, while providing modern machine tools with the proper level of production flexibility in combination with guaranteed high values of processing productivity and the required level of parts manufacturing quality. Insufficient or excess capacity of technological equipment leads to a decrease in its economic efficiency, an increase in capital costs and, as a result, an increase in the cost of production. In the machine tool industry, which is a strategically significant and basic industry for the modernization of mechanical engineering, there is a special interest in the development of a new type of technological equipment that makes it possible to implement methods for modifying the surface layers of parts by processing it with concentrated energy sources. The combination of two processing technologies (mechanical and surface-thermal operations) in the conditions of integrated equipment makes it possible to level the shortcomings of monotechnologies and obtain new effects that are unattainable when using technologies separately. Ensuring an optimal level of quality — one of the unconditional requirements of a market economy — is a priority when developing the overall concept of technological equipment. Thus, it should be noted that the required and specific set of consumer properties are laid down during the design. And, therefore, the problem of quality optimization belongs to the field of forecasting and should be comprehensively addressed at the initial stage of developing the concept of technological equipment. The purpose of this research is to rationally choose the objects of modernization when carrying out work related to retrofitting a standard machine tool system with an additional concentrated energy source. Methods: Theoretical studies of the possible structural composition and layout of hybrid equipment during the integration of mechanical and surface-thermal processes were carried out taking into account the main provisions of structural synthesis and components of metal-cutting systems. During the research, issues related to the main provisions of system analysis, the geometric theory of surface formation, the design of metal-cutting equipment, methods of mathematical and computer modeling were raised. Results and discussion. Theoretical studies is found that currently, most of the parameter-oriented (dimension) series of general-purpose metal-cutting machines, built according to the law of geometric progression with a constant denominator, are the cause of multiple duplication of individual size ranges on machines of the same series. This gives grounds to talk about an unreasonable increase in the number of its members and, as a result, to an increase in the cost of designing, manufacturing and operating equipment. The authors adhere to the point of view that in order to ensure maximum efficienc","PeriodicalId":42889,"journal":{"name":"Obrabotka Metallov-Metal Working and Material Science","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2023-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41767986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-13DOI: 10.17212/1994-6309-2023-25.2-93-103
A. Balanovsky, V. V. Nguyen, N. Astafieva, R. Gusev
Introduction. One of the effective thermochemical methods for increasing the hardness of steel is boronizing by diffusion of boron atoms into the steel surface at high temperatures. As a result of boronizing, coatings are formed on the steel surface, consisting of columnar crystals of FeB and Fe2B. The volume fraction of phases and the thickness of the coatings depend on the heating temperature and the chemical composition of the base material and the saturating medium. The main disadvantage of these boronized layers is its high brittleness. Boronizing by plasma heating is one of the alternatives to the diffusion boronizing process to minimize the brittleness of the boronized layer. The purpose of the work: to form boride coatings on low-carbon steel using plasma-jet hard-facing. The research methods are: determination of the content of chemical elements using an electron probe micro-analyzer, metallographic studies, analysis of the phase composition of the boronized layer, as well as measurement of the microhardness of the coating after plasma-jet hard-facing. In this work boronized layers obtained on low-carbon steel 20 by plasma-jet hard-facing of a boron-containing coating are studied. Powdered amorphous boron was used as an alloying element. The parameter varied during plasma-jet hard-facing process is the current strength (120 A, 140 A and 160 A). Results and discussions. Based on the studies performed, it is found that it is possible to form boronized layers on the steel surface using plasma-jet hard-facing method. It is noted that the surface layer of the coating of the 1st and 2nd specimens after plasma-jet hard-facing has a heterogeneous structure, consisting of rows of different zones. The first zone has a hypereutectic structure, which consists of primary borides FeB and Fe2B, located in the eutectic, consisting of Fe2B and α-Fe. The second zone above the boundary with the base metal is represented by eutectic colonies composed of Fe2B and α-Fe. The third specimen is characterized by a hypoeutectic structure consisting of boride eutectic and primary dendrites of the α-solid solution of boron in iron. The maximum hardness is fixed on the surface of the first specimen and is 1,575 HV. The depth of the hardened layer increases with increasing current, but the hardness value and boron content decrease after treatment. The slight hardness gradient observed over the depth of the coating, as well as the gradual decrease in hardness due to the presence of the transition zone, are considered favorable for good adhesion of the boronized layer to the surface of the base material.
{"title":"Structure and properties of low carbon steel after plasma-jet hard-facing of boron-containing coating","authors":"A. Balanovsky, V. V. Nguyen, N. Astafieva, R. Gusev","doi":"10.17212/1994-6309-2023-25.2-93-103","DOIUrl":"https://doi.org/10.17212/1994-6309-2023-25.2-93-103","url":null,"abstract":"Introduction. One of the effective thermochemical methods for increasing the hardness of steel is boronizing by diffusion of boron atoms into the steel surface at high temperatures. As a result of boronizing, coatings are formed on the steel surface, consisting of columnar crystals of FeB and Fe2B. The volume fraction of phases and the thickness of the coatings depend on the heating temperature and the chemical composition of the base material and the saturating medium. The main disadvantage of these boronized layers is its high brittleness. Boronizing by plasma heating is one of the alternatives to the diffusion boronizing process to minimize the brittleness of the boronized layer. The purpose of the work: to form boride coatings on low-carbon steel using plasma-jet hard-facing. The research methods are: determination of the content of chemical elements using an electron probe micro-analyzer, metallographic studies, analysis of the phase composition of the boronized layer, as well as measurement of the microhardness of the coating after plasma-jet hard-facing. In this work boronized layers obtained on low-carbon steel 20 by plasma-jet hard-facing of a boron-containing coating are studied. Powdered amorphous boron was used as an alloying element. The parameter varied during plasma-jet hard-facing process is the current strength (120 A, 140 A and 160 A). Results and discussions. Based on the studies performed, it is found that it is possible to form boronized layers on the steel surface using plasma-jet hard-facing method. It is noted that the surface layer of the coating of the 1st and 2nd specimens after plasma-jet hard-facing has a heterogeneous structure, consisting of rows of different zones. The first zone has a hypereutectic structure, which consists of primary borides FeB and Fe2B, located in the eutectic, consisting of Fe2B and α-Fe. The second zone above the boundary with the base metal is represented by eutectic colonies composed of Fe2B and α-Fe. The third specimen is characterized by a hypoeutectic structure consisting of boride eutectic and primary dendrites of the α-solid solution of boron in iron. The maximum hardness is fixed on the surface of the first specimen and is 1,575 HV. The depth of the hardened layer increases with increasing current, but the hardness value and boron content decrease after treatment. The slight hardness gradient observed over the depth of the coating, as well as the gradual decrease in hardness due to the presence of the transition zone, are considered favorable for good adhesion of the boronized layer to the surface of the base material.","PeriodicalId":42889,"journal":{"name":"Obrabotka Metallov-Metal Working and Material Science","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2023-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43088317","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-15DOI: 10.17212/1994-6309-2023-25.1-110-130
A. Filippov, E. Khoroshko, N. Shamarin, E. Kolubaev, S. Tarasov
Introduction. Additive technologies make it possible to curb material expenses by reducing allowances for the final dimensional machining of workpieces. For such expensive materials as copper and copper alloys, this method is considerably attractive from a perspective of increasing resource efficiency in production. The operational properties of the C65500 alloy manufactured using additive technologies have not been fully studied and require additional research. The aim of the work is to study the structural and phase state, mechanical and operational properties of C65500 bronze specimens printed using electron beam additive manufacturing technology. In the work, specimens made of C65500 wire with different heat input values are studied, some of which were subjected to thermal treatment and mechanical processing, as well as specimens, manufactured using multi-wire technology. The work uses such research methods as the study of corrosion resistance of bronze specimens using a potentiostat, confocal laser scanning microscopy, friction tests and X-ray phase analysis. Results and discussion. Processing of specimens by plastic deformation (compression) and subsequent annealing leads to the most serious structural changes. Based on X-ray phase analysis, it is found that higher silicon content is observed in the case of the addition of silumins to bronze. The study of mechanical properties shows that the specimens, printed using multi-wire technology, have the highest strength properties. During tribological testing, fluctuations in the value of the friction coefficient are revealed, due to the scheme of the experiment and the combined adhesive-oxidative mechanism of specimens’ wear. The addition of 10 wt.% aluminum filament to bronze in the additive manufacturing process is an effective means for increasing the resistance of the material to electrochemical corrosion and increasing its wear resistance.
{"title":"Study of the properties of silicon bronze-based alloys printed using electron beam additive manufacturing technology","authors":"A. Filippov, E. Khoroshko, N. Shamarin, E. Kolubaev, S. Tarasov","doi":"10.17212/1994-6309-2023-25.1-110-130","DOIUrl":"https://doi.org/10.17212/1994-6309-2023-25.1-110-130","url":null,"abstract":"Introduction. Additive technologies make it possible to curb material expenses by reducing allowances for the final dimensional machining of workpieces. For such expensive materials as copper and copper alloys, this method is considerably attractive from a perspective of increasing resource efficiency in production. The operational properties of the C65500 alloy manufactured using additive technologies have not been fully studied and require additional research. The aim of the work is to study the structural and phase state, mechanical and operational properties of C65500 bronze specimens printed using electron beam additive manufacturing technology. In the work, specimens made of C65500 wire with different heat input values are studied, some of which were subjected to thermal treatment and mechanical processing, as well as specimens, manufactured using multi-wire technology. The work uses such research methods as the study of corrosion resistance of bronze specimens using a potentiostat, confocal laser scanning microscopy, friction tests and X-ray phase analysis. Results and discussion. Processing of specimens by plastic deformation (compression) and subsequent annealing leads to the most serious structural changes. Based on X-ray phase analysis, it is found that higher silicon content is observed in the case of the addition of silumins to bronze. The study of mechanical properties shows that the specimens, printed using multi-wire technology, have the highest strength properties. During tribological testing, fluctuations in the value of the friction coefficient are revealed, due to the scheme of the experiment and the combined adhesive-oxidative mechanism of specimens’ wear. The addition of 10 wt.% aluminum filament to bronze in the additive manufacturing process is an effective means for increasing the resistance of the material to electrochemical corrosion and increasing its wear resistance.","PeriodicalId":42889,"journal":{"name":"Obrabotka Metallov-Metal Working and Material Science","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2023-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48052003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-15DOI: 10.17212/1994-6309-2023-25.1-85-97
D. Lobanov, Olesya Rafanova
Introduction. Trends in the development and application of modern machine-building systems somehow create the problem of analysis and choice in the presence of alternative objects, or with a large number of comparison criteria - indicators of the effectiveness of objects or systems. The main difficulties in optimizing the solution for designing production systems depend on complex technological problems: a large number of influencing factors and the absence of patterns. The choice of effective objects and systems is often a complex and multi-criteria process that requires a lot of time and, as a result, reduces the efficiency of the organization of production preparation. In this regard, for the preparation and adoption of technical and economic decisions of various complexity in production conditions, a systematic approach is required using the most rational forms and methods of organizing production. The purpose of the work: to create a generalized methodology for the criteria analysis of multivariant systems. The methods of investigation. A methodology is proposed aimed at improving the efficiency of the organization of pre-production due to a reasonable choice from a large number of options. The choice of a rational solution option is based on the ranking of indicators by priority at the time of making a reasonable decision in a specific situation and the type of object and system under consideration. Indicators can be variable, taking into account the specifics of production. Results and Discussion. A comparative analysis of the process of edge cutting machining of the STEF-1 fiber-glass polymer composite material with an interlocking side mill carrying various insert materials is conducted as an example of the practical application of the proposed methodology. As comparison parameters, the period of technological tool life, cutting performance and reduced costs in the implementation of cutting are taken. According to the results of a comparative multi-criteria analysis carried out according to the presented method, it follows that the priority in the system under consideration with the specified parameters for the implementation of the technology is the tool equipped with WC–3Co alloy inserts, which has the highest value of the weight criteria coefficient. According to the results of the analysis, a tool equipped with WC–2TaC–6Co alloy inserts is close in rationality, which allows recommending it as an analogue when choosing. The scope of the proposed application of the methodology is seen if it is necessary to analyze complex multivariant systems/objects. The objects/systems can be both variants of scientific solutions under various conditions of comparability, as well as design, technological solutions, structural and instrumental materials at the selection stage in the design and technological preparation of production, variants of the system implementation algorithm. The comparison parameters can be physical, mechanical, technological,
{"title":"Methodology for criteria analysis of multivariant system","authors":"D. Lobanov, Olesya Rafanova","doi":"10.17212/1994-6309-2023-25.1-85-97","DOIUrl":"https://doi.org/10.17212/1994-6309-2023-25.1-85-97","url":null,"abstract":"Introduction. Trends in the development and application of modern machine-building systems somehow create the problem of analysis and choice in the presence of alternative objects, or with a large number of comparison criteria - indicators of the effectiveness of objects or systems. The main difficulties in optimizing the solution for designing production systems depend on complex technological problems: a large number of influencing factors and the absence of patterns. The choice of effective objects and systems is often a complex and multi-criteria process that requires a lot of time and, as a result, reduces the efficiency of the organization of production preparation. In this regard, for the preparation and adoption of technical and economic decisions of various complexity in production conditions, a systematic approach is required using the most rational forms and methods of organizing production. The purpose of the work: to create a generalized methodology for the criteria analysis of multivariant systems. The methods of investigation. A methodology is proposed aimed at improving the efficiency of the organization of pre-production due to a reasonable choice from a large number of options. The choice of a rational solution option is based on the ranking of indicators by priority at the time of making a reasonable decision in a specific situation and the type of object and system under consideration. Indicators can be variable, taking into account the specifics of production. Results and Discussion. A comparative analysis of the process of edge cutting machining of the STEF-1 fiber-glass polymer composite material with an interlocking side mill carrying various insert materials is conducted as an example of the practical application of the proposed methodology. As comparison parameters, the period of technological tool life, cutting performance and reduced costs in the implementation of cutting are taken. According to the results of a comparative multi-criteria analysis carried out according to the presented method, it follows that the priority in the system under consideration with the specified parameters for the implementation of the technology is the tool equipped with WC–3Co alloy inserts, which has the highest value of the weight criteria coefficient. According to the results of the analysis, a tool equipped with WC–2TaC–6Co alloy inserts is close in rationality, which allows recommending it as an analogue when choosing. The scope of the proposed application of the methodology is seen if it is necessary to analyze complex multivariant systems/objects. The objects/systems can be both variants of scientific solutions under various conditions of comparability, as well as design, technological solutions, structural and instrumental materials at the selection stage in the design and technological preparation of production, variants of the system implementation algorithm. The comparison parameters can be physical, mechanical, technological, ","PeriodicalId":42889,"journal":{"name":"Obrabotka Metallov-Metal Working and Material Science","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2023-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47518509","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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