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1
Korolkova, L. I., and N. M. Mashrabov. "Surface Hardening of Parts Arc." Materials Science Forum 843 (February 2016): 225–30. http://dx.doi.org/10.4028/www.scientific.net/msf.843.225.
Повний текст джерелаАнотація:
The paper presents the results of studies aimed at justifying and developing the ways and means of cylindrical parts made of hardenable alloys surface hardening by heating of the electric arc between the inert electrode and the element. The shapes of electrode sharpening and the position of the electrode relative to the element are substantiated. The sequence of surface hardening operations is revealed and the critical rate of cooling is determined and its value is proved with numerical experiments. It was necessary to develop a program for calculating temperature fields in details, with a difference-differential scheme obtained from a combination of explicit and implicit schemes being developed for the first time. A number of investigations were conducted to determine the mechanical properties, the residual stresses, the fatigue resistance, the hardness and the microstructure of hardened layers. As a result, the surface hardening technology is recommended for reconditioning and manufacturing cylindrical machine elements.
2
Zubchenko, O. I., and V. B. Margolin. "Combined hardening of the working surface of machine parts." Strength of Materials 19, no. 11 (November 1987): 1591–96. http://dx.doi.org/10.1007/bf01523052.
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3
Yatsenko, V. K., and N. A. Kostenko. "Criteria for evaluating the surface strain-hardening of machine parts." Strength of Materials 17, no. 3 (March 1985): 325–28. http://dx.doi.org/10.1007/bf01755915.
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4
Yakovleva, A. P. "Improving the Durability of Machine Parts Using a Combined Method." Materials Science Forum 946 (February 2019): 37–41. http://dx.doi.org/10.4028/www.scientific.net/msf.946.37.
Повний текст джерелаАнотація:
A combined processing method for improving the performance features of machine parts (durability), that works under intense wear and high lubricated or boundary friction has been developed; a working installation based on a CNC lathe has been developed. The research on resulting surface hardness material of steels: С45Е; 1.1191 (1 option); SA-240 TP 310S (2 option); 34CrNiMo6, 36CrNiMo4, 40NiCrMo4KD (3 option) and hardening depth variation under different combined processing conditions has been carried out. Surface roughness parameters have been calculated. The suggested method can increase the operational life of a machine part due to improving features, such as surface hardening, creating a favorable surface topography.
5
Оdosii, Z. М., V. Ya Shymanskyi, and B. V. Pindra. "Influence of reinforcing plastic surface deformation on surface performance of machine parts." Scientific Bulletin of Ivano-Frankivsk National Technical University of Oil and Gas, no. 2(47) (December 26, 2019): 7–14. http://dx.doi.org/10.31471/1993-9965-2019-2(47)-7-14.
Повний текст джерелаАнотація:
The performance of the machines part reinforcement using surface plastic deformation shall be considered as formation of the whole complex of surface parameters and quality and their impact on the operational properties of these parts. The main surface quality parameters, affecting the performance of machine parts are geometric (microgeometry, wavelength, roughness, shape of inequalities, the size of the supporting surface, the direction of the traces of processing); physical parameters (structure, degree and slander depth, residual stresses in the surface layer). In the machine building, many methods of superficial plastic deformation are used for part reinforcement; these methods essentially differ in the scheme of impact of the surface deforming part to be treated. After analyzing the results obtained by scientists, involved in research on surface plastic deformation of surface layers and surfaces of parts, it was found that after hardening, practically all structural changes contribute to reinforcement of the surface layer material and increase the plastic deformation resistance. Increasing the density of dislocations and the separation of carbides, which block the shear slides and create obstacles to the movement of dislocations. Due to these changes, resistance to formation and spread of fatigue cracks have increased. The treatment depth, magnitude of residual stresses and increase in hardness depends on the original structure and chemical composition of the material. Reinforcement regimes have significant effects on the wear resistance. Use of diamond smoothing, vibration processing, combined methods (surface plastic deformation in combination with other reinforcement methods, as well as the use of a combined tool) opens up new possibilities for increasing the quality characteristics of the surface and the surface layer of parts, and accordingly, increasing their operational properties with all the diversity and complexity of used processes. Based on the results of the studies, practical recommendations on the application of methods of hardening by surface plastic deformation of machine parts and a methodology for designing technological processes for their manufacture considering manufacturing capabilities are proposed.
6
Pukhov, E. V., V. L. Sidorenkov, and I. V. Shchegolev. "Determining the temperature values on the surface of complex curvilinearly bent agricultural machine parts during the formation of powder coatings by thermal methods." IOP Conference Series: Earth and Environmental Science 845, no. 1 (November 1, 2021): 012139. http://dx.doi.org/10.1088/1755-1315/845/1/012139.
Повний текст джерелаАнотація:
Abstract The development of modern technologies for the restoration and hardening of agricultural machine parts require the development of a mathematical apparatus that simulates the involved processes. For this purpose, the models should take into account the technological features of the process of hardening and restoration of machine parts, including: cleaning; determination of geometric indicators; surface preparation; choice of technology; subsequent machining of the resulting surface; surface quality control. One of the priority directions in the development of technologies for the restoration and hardening of parts is the formation of coatings on machine parts using powder materials applied by the gas-thermal method. One of the most important conditions for obtaining high-quality coatings is temperature control on the surface of the part. In this regard, it is of scientific interest to study the effect of the distance from the surface of the part to the flame nozzle when applying self-fluxing powder on the time-average temperature at the point of coating, the maximum temperature on the back side of the part, and the total power transferred to the part by the gas burner. This paper presents a mathematical model for determining the above-mentioned influence, and also presents the results obtained using a computer program. The novelty of the model is the ability to use it to study temperature values for complex curved-bent machine parts (crankshafts and camshafts of agricultural machines). To check the reliability of the dependences obtained, experiments were carried out and the convergence with theoretical developments was confirmed.
7
KOLOSOVSKIY, A. M., E. B. TRISTANOVA, and E. F. CHERKASHINA. "THE MODERN LASER METHODS OF MACHINE AND TOOL PARTS HARDENING ANALYSIS." Fundamental and Applied Problems of Engineering and Technology, no. 1 (2021): 53–59. http://dx.doi.org/10.33979/2073-7408-2021-345-1-53-59.
Повний текст джерелаАнотація:
The article offers a retrospective analysis of the development of laser and combined lasers based on the use of laser radiation methods of hardening the responsible parts of machines and tools. It is shown that the combination of laser radiation and other advanced technological methods creates contact surface layers of machine with unique physical-mechanical and operational properties forming is the current and promising direction in an improving technologies for their application with high physical and mechanical properties of responsible parts.
8
Buglaev, Anatoly M. "Device for Wood-Cutting Tool Hardening." Lesnoy Zhurnal (Forestry Journal), no. 5 (October 15, 2021): 134–41. http://dx.doi.org/10.37482/0536-1036-2021-5-134-141.
Повний текст джерелаАнотація:
Choosing effective methods and devices for surface hardening of wood-cutting tools is problematic due to the variety of their designs and operating conditions. In this regard, the development of such devices becomes an urgent task. According to the literature, one of the effective methods for increasing the service life of machine parts and tools is electrospark hardening or electrospark alloying. Industrial electrospark installations such as “EFI” (electrophysical measurements) and “Elitron” with manual vibrators are used for electrospark hardening. However, using manual vibrators significantly increases the labour intensity and hardening time. Moreover, the surface quality after hardening with manual vibrators is often unsatisfactory. Various mechanized installations have been developed in order to reduce the labour intensity of electrospark hardening. Nevertheless, these installations are designed to harden specific parts and do not allow hardening tools of various designs, including woodcutting tools. The surface quality after hardening in mechanized installations does not always satisfy the customer. Further surface plastic deformation treatments, such as rolling and unrolling with rollers and balls, as well as diamond burnishing, are often used to improve the surface quality after electrospark hardening. The surface quality after additional processing by these methods boosts, although the labour intensity and cost of the hardening process increase. To increase the wear resistance of machine parts and tools, it is reasonable to reduce the height parameters of roughness, increase microhardness, and form the residual compressive stresses, which is ensured by the methods of surface plastic deformation. In this regard, it becomes necessary to use electrospark hardening simultaneously with surface plastic deformation. The work presents the design and features of using the device for hardening. The device was used to strengthen the thicknesser machine knives, which made it possible to almost double their durability. Applying this device, in comparison with using the electrospark hardening with a manual vibrator, reduces the roughness of the hardened surface and improves the surface quality of the processed workpieces. The modes of hardening have been installed, making it possible to effectively harden wood-cutting tools. For citation: Buglaev A.M. Device for Wood-Cutting Tool Hardening. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 5, pp. 134–141. DOI: 10.37482/0536-1036-2021-5-134-141
9
Krioni, N. K., A. A. Mingazheva, and A. Yu Kononova. "Nitriding of Parts of Alloyed Steels with High-Energy Surface Treatment." Materials Science Forum 843 (February 2016): 85–90. http://dx.doi.org/10.4028/www.scientific.net/msf.843.85.
Повний текст джерелаАнотація:
The increased wear resistance of machine parts continues to be one of the most urgent problems of modern machine engineering. Despite the intensive development of different ways of protective hardening treatment, the technologies based on thermochemical methods are quite popular and widely used to improve the performance characteristics of parts. Nitriding of the surface layer of parts as a way of improving their reliability has a considerable history of development and improvement and continues to develop relying on scientific advances in the field of high energies. However, tightened operating conditions of modern machines and equipment require creating new nitriding technologies that can provide a complex of properties of parts surface layer and therefore specified performance characteristics. This article is devoted to the research and development of a new technology of nitriding parts made of alloyed steels. The specific feature of the proposed nitriding technology consists in creating the conditions for thermochemical treatments of parts allowing forming a nitrided layer which is homogeneous in structure and composition.
10
KOLOSOVSKII, A. M., V. I. VICHTEVSKII, E. F. CHERKASHINA, and E. B. TRISTANOVA. "THE DEVELOPMENT OF COMBINED ELECTROPHYSICAL METHODS OF MACHINE AND INSTRUMENT PARTS HARDENING ANALYSIS." Fundamental and Applied Problems of Engineering and Technology 2 (2021): 77–85. http://dx.doi.org/10.33979/2073-7408-2021-346-2-77-85.
Повний текст джерелаАнотація:
The article proposes an analysis of the development of combined electrophysical methods of hardening machine parts and tools based on the use of radiation (laser, electro-beam, ultrasonic, etc.) processing and electromagnetic fields. It is shown that the current and promising direction in improving the performance of the contact surface layers of machine parts, creating high-performance coatings (as well as technologies for their application) with high physical and mechanical properties of responsible parts is the combination of high-energy (laser, electronic, etc.) radiation and electromagnetic fields as a technological factor, as well as other sources of technological energy, which are advanced electrophysical methods of forming working surfaces of mechanical parts of mechanical and mechanical components.
11
Metel, Alexander, Sergey Grigoriev, Yury Melnik, Marina Volosova, and Enver Mustafaev. "Surface Hardening of Machine Parts Using Nitriding and TiN Coating Deposition in Glow Discharge." Machines 8, no. 3 (July 24, 2020): 42. http://dx.doi.org/10.3390/machines8030042.
Повний текст джерелаАнотація:
Surface hardening of machine parts substantially improves their performance. The best results are obtained when combined hardening consists of surface nitriding and subsequent deposition of hard coatings. The nitriding of machine parts immersed in the plasma of glow coatings have been studied, and the study results are presented. Titanium atoms for coating synthesis are obtained via titanium evaporation in a hollow molybdenum anode of the discharge. Stable evaporation of titanium occurs only when the power density of electrons heating the liquid titanium does not exceed ~500 W/cm2. To start evaporation, it is only necessary to reduce the gas pressure to 0.02 Pa. To stop evaporation, it is enough to increase the gas pressure to 0.1 Pa. Fast argon and nitrogen atoms used for cleaning the machine parts, heating them, and bombarding the growing coating are obtained using a grid composed of plane-parallel plates under high negative voltage and immersed in plasma.
12
Djema, Mohamed Amine, Khaled Hamouda, Anatoly P. Babichev, Djamel Saidi, and D. Halimi. "The Impact of Mechanical Vibration on the Hardening of Metallic Surface." Advanced Materials Research 626 (December 2012): 90–94. http://dx.doi.org/10.4028/www.scientific.net/amr.626.90.
Повний текст джерелаАнотація:
One of functional parameters which have a big influence on the reliability of machine is the surface quality of mobile and immobile parts. The quality working ability of the surface in contact is depending of their surfaces strength. In this regard, we used vibro-mechanical treatment to increase the hardness of the contact surfaces which is considered as formed surface of plastic deformation. The formed plastic deformation surface is also a kind of micro relief surface, characterized by multitude closed and superimposed on each other traces of contact with the particles working environment cultivated surface. The quality of the surface resulting from the vibro-impact treatment, provide a sufficiently high wear parts. This paper presents experimental results of using the vibro-impact treatment on surface fatigue strength using samples of steels, aluminums and titans alloys. The objective of this study is to improve performance functional surfaces in contact by choosing optimal hardening parameters.
13
Veretelnik, Oleg, Mykola M. Tkachuk, Serhii Kravchenko, Mariia Saverska, Serhii Kutsenko, Andrey Grabovskiy, Illia Klochkov, and Mykola А. Tkachuk. "RESEARCH AND EXPERIMENTAL STUDIES OF STRESS-STRAIN STATE OF DISCRETE-CONTINUAL HARDENED MACHINE PARTS." Bulletin of the National Technical University «KhPI» Series: Engineering and CAD, no. 2 (December 30, 2021): 5–21. http://dx.doi.org/10.20998/2079-0775.2021.2.03.
Повний текст джерелаАнотація:
Research and experimental studies of stress-strain state of discrete-continual hardened machine parts are presented in this work. This hardening method is distinguished by incorporation of numerous hard spots into the surface layer of one of the bodies. Meanwhile the other part is covered by a continuous corundum layer. Correspondingly, a network of microchannels for lubricant is formed between the bodies. Furthermore the contact loads are intensified in the vicinity of the harder material in the discrete zones. As a result the strength and durability of the loaded parts is increased. The technological parameters of the hardening process have great impact on the resulting characteristics. In particular, this concern the shape of the discrete hardening zones and the material properties of the corundum layer. These factors were varied in stress-strain analyses of the contacting bodies. The dependence of the stress-strain state characteristics on the varied parameters was established. The justified recommendations regarding the technological parameters of the discrete-continual hardening have been developed. Keywords: stress-strain state, discrete-continual hardening, contact interaction, finite element method, contact pressure, machine parts
14
Grum, Janez, and Uros Zupanc. "Surface Analysis after Shot Peening Processing of ENAW 7075 Aluminium." Materials Science Forum 589 (June 2008): 385–90. http://dx.doi.org/10.4028/www.scientific.net/msf.589.385.
Повний текст джерелаАнотація:
Shot peening has been a very important and well-known surface cold-hardening process applicable to various machine parts and tool surfaces for quite a long time since it improves fatigue strength and corrosion resistance of stressed surfaces. Hardening by shot peening provides, because of plastic deformation, an increase in hardness and induces compressive residual stresses in the thin surface layer, which reduces material fatigue and prevents the generation and propagation of cracks. The present paper reports of results of shot peening hardening of specimens made of 7075-T651 aluminium. They were surface-hardened by steel shots M170 with Almen hardening intensity of 8A and 12A respectively and by glass beads GP165 with Almen hardening intensity of 12A. The steel shots and glass beads had the same diameter but differed considerably in hardness and density. The surface condition after shot peening processing was assessed in terms of surface integrity, which establishes a relation between processing conditions and roughness state and hardened-layer depth supported by an analysis of residual-stress variations.
15
Afonin, A. N., A. I. Larin, and A. V. Makarov. "HETEROGENEOUS HARDENING OF MACHINES PARTS BY SURFACE PLASTIC DEFORMATION." Izvestiya Visshikh Uchebnykh Zavedenii. Chernaya Metallurgiya = Izvestiya. Ferrous Metallurgy 58, no. 11 (January 23, 2016): 823–27. http://dx.doi.org/10.17073/0368-0797-2015-11-823-827.
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16
Aftanaziv, Ivan, Lily Shevchuk, Orissa Strogan, Lesya Strutynska, and I. Strogan. "Increasing the durability of cylindrical parts of wheelcarms of railway." Mechanics and Advanced Technologies 5, no. 1 (June 23, 2021): 136–45. http://dx.doi.org/10.20535/2521-1943.2021.5.1.234478.
Повний текст джерелаАнотація:
A description of a new design of a vibrating machine for strengthening the surface plastic deformation of cylindrical long parts, in particular stabilizers of wheeled carriages of railway cars, is given. The main design and technological parameters of the process of vibration – centrifugal strengthening of these parts are outlined. The influence of technological parameters of this hardening process on such basic indicator of hardening processing as depth of hardening is experimentally investigated on cylindrical samples from 45 steel. Mathematical dependences for the choice of optimal values of design and technological parameters of this hardening treatment are given.
The list of long cylindrical parts for which vibration – centrifugal strengthening treatment is suitable and effective is outlined, among which torsion shafts of suspension of military tanks, axles of wheels of railway transport, drilling and casing pipes of gas and oil wells.
17
Krasheninnikov, Valeriy V., Аleksandr G. Malikov, Аnatolii M. Orishich, and Аleksandr O. Tokarev. "Investigation of the Laser-Powder Cladding Effect on Steel Surface Hardening." Applied Mechanics and Materials 788 (August 2015): 52–57. http://dx.doi.org/10.4028/www.scientific.net/amm.788.52.
Повний текст джерелаАнотація:
The investigation was carried out in the laser-technological complex with the power up to 8 kW, ITAM SB RAS. An inert-gas jet was supplied coaxially with the beam. A protective nozzle from which gaseous Ar was injected was used to protect the hardening joint. The parameters of the laser hardening process with the surface alloying was optimized on the samples of low-carbon steel 20, construction steel 45, and spring steel 65G.Special cladding powders containing carbon, manganese, nickel, chromium, molybdenum, tungsten, silicon, boron, and nitrogen were chosen for laser-powder cladding. They are intended for cladding wear-resistant layers onto machine parts, tools and equipment operated under abrasion-wear conditions with moderate shock loading.It was found that an optimal radiation power was 2 kW. Extra water cooling of treated parts is unpractical during laser hardening because it did not improve the hardening effect. The best effect of surface alloying was reached when the powder of rapid tool steel Р6М5 was injected in the liquid metal pool. High hardness of the clad layer remained at further heating up to 550°C. The use of laser thermal treatment and laser-powder cladding provides thermal hardening and enables increasing hardness and hence wear resistance of low-carbon steel parts by 3 - 4 times, whereas the base part remains viscous.
18
BELASHOVA, I. S., L. N. RABINSKI, and O. V. TURSHAVINA. "EVALUATION OF HARDENING EFFICIENCY WITH CONVECTIVE HEAT AND MASS TRANSFER MECHANISM DURING LASER SURFACE ALLOYING IN REFLOW MODE." Periódico Tchê Química 16, no. 33 (March 20, 2019): 498–504. http://dx.doi.org/10.52571/ptq.v16.n33.2019.513_periodico33_pgs_498_504.pdf.
Повний текст джерелаАнотація:
The modern stage of equipment development imposes increased requirements for the performance characteristics of parts. Different components and parts of machines, metal-cutting tools and metal structural elements work in the conditions of high friction, high specific loads, high temperatures, a wide range of speeds and impact of aggressive media, for instance. Therefore, improvement the quality, reliability, economical efficiency and productivity of machines, tools, equipment and other engineering products as well as reduction of their specific material consumption and energy consumption is achieved primarily by the use of materials and progressive strengthening technology that improve the hardening, wear resistance, corrosion resistance and other physical and mechanical properties of machine parts and tool. Therefore, the main objective of the paper was to evaluate the mass-transfer during laser surface alloying in the reflow mode. To evaluate the effectiveness of surface hardening technology, it was proposed to use two new parameters – reduced wear and reduced integrated micro hardness of the modified surface layer. Based on an analysis of the experimental data on the wear of a cutter made of HVG and U10 steel, processed by a laser with smears in the reflow mode, the existence of a correlation between the entered parameters is demonstrate and the regression equation is obtained. The proposed approach to evaluating the effectiveness of surface hardening can be used not only in the special case of laser modification but also for any other technology for creating gradient and functional coatings.
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Li, Guang Hong, and Chao Wu. "Development of Open CNC System of Constant Linear Speed Quenching Machine." Applied Mechanics and Materials 312 (February 2013): 719–22. http://dx.doi.org/10.4028/www.scientific.net/amm.312.719.
Повний текст джерелаАнотація:
The inconsistent requirement of surface and core section can be solved through system construction of open CNC quenching machine based on PC + motion control card, to realize surface quenching of mechanical parts. The establishment of mathematical model and algorithm researching of the hardening methods is studied in this paper, especially for the outer edge of the non-circular discoid parts, so as to guarantee the consistence of quenching. The result of the experiments shows that the workpiece such as gear, crankshaft, cam and etc. can obtain higher strength, hardness, wear resistance on the surface, while maintaining original good toughness in the core section.
20
Blumenstein, Valeriy, Maksim Mahalov, and Oleg Ostanin. "Simulation and Calculation of Residual Stresses in Mining Machines Components." E3S Web of Conferences 41 (2018): 03012. http://dx.doi.org/10.1051/e3sconf/20184103012.
Повний текст джерелаАнотація:
Technologies of surface plastic deformation (SPD) provide a hardening effect and create compressive residual stresses in the surface layer of mining machine parts. This leads to a significant increase in the limit of endurance and fatigue cyclic life, increases the life in fretting conditions, improves the quality of assembly joints fit, etc. Very complex are both the physical nature of the occurrence and the estimation of residual stresses, since the machining processes are related to complex nonmonotonic types of loading. The study shows the relevance of the development of computational methods for determining residual stresses in the processes of hardening treatment of critical surfaces of mining machine parts. At the same time, the design and development of experimental nondestructive express methods based on the determination of various physical parameters (acoustic, magnetic noise, coercive force, etc.) are relevant and promising. A model of the process is developed and numerical calculations of the residual stresses arising during the SPD treatment are carried out. The results of the calculations are in good agreement with the experimental data.
21
Gurey, V. I. "The investigation of forces' component during frictional hardening of cylindrical surfaces of machine parts." Scientific Bulletin of Ivano-Frankivsk National Technical University of Oil and Gas, no. 2(49) (December 30, 2020): 81–90. http://dx.doi.org/10.31471/1993-9965-2020-2(49)-81-90.
Повний текст джерелаАнотація:
Friction treatment refers to methods of surface hardening (strengthening) using highly concentrated energy sources. After processing in the surface layers of the parts a hardened (reinforced) white layer with a nanocrystal-line structure is formed. Friction treatment of the cylindrical surfaces of the samples was performed on an upgrad-ed lathe (model 16K20), on which instead of a tool-post was installed a special device for autonomous tool drive. A metal disk made of steel 45 is used as a tool. Mineral oil with active additives containing polymers was used as a technological medium in the process of friction treatment. A special dynamometer was developed to study the components of the force that occurs in the contact area of the tool-part during the frictional hardening of the cy-lindrical surfaces of the parts. The immovable elastic elements of the dynamometer are fixed on conical holes in the rear headstock and spindle. To make rotation impossible of the elastic element in the spindle, it is mounted in the adapter bushing through the bearings. Studies have shown that the modes of friction treatment significantly affect the normal Py and the tangential component Pz of the force that occurs in the contact area of the tool-part. The increasing of the part’s rotational velocity slightly affects into magnitude of the force components that occurs in the contact area of the tool-part during processing with the longitudinal feed S = 0.3 mm/rev and the depth of pressing the tool into the workpiece t = 0.1 mm. When increase the depth of pressing the tool into the workpiece from 0.1 to 0.3 mm and part’s rotational velocity equal n = 40 rpm, the normal force component Py increased from 380 N to 690 N, and the tangential component Pz – from 28 N to 47 N. And in that the same time increasing the part’s rotational velocity to 125 rpm leads to an increase the normal component Py from 510 N to 1160 N, and the tangential component Pz – from 38 N to 69 N.
22
Tang, Yu Lan, Ya Ting He, Guo Zhi Liu, Jing Xiang Fu, Hong Sun, Ke Zhang, and Yu Hou Wu. "Effect of Surface Relaxation on Characteristics of Nanomachined Surface." Advanced Materials Research 211-212 (February 2011): 742–46. http://dx.doi.org/10.4028/www.scientific.net/amr.211-212.742.
Повний текст джерелаАнотація:
With the development of Micro-electro-mechanical systems (MEMS) and Nano-electro-mechanical systems (NEMS), dimension of their parts is required to nanometer scale, and the characteristics of machined-surface of nano-scale parts affect strongly its application. Surface relaxation plays an important role to the characteristics of the machined-surface. In this paper, machined-surface of monocrystal copper used as the specimen of surface relaxation, and its surface relaxation process is simulated. The influences of surface relaxation on surface energy, atom array, surface roughness, surfaces hardness and surface residual stress of the monocrystal copper are analyzed. Results show that surface energy and surface hardness decrease due to relaxation; work-hardening can’t be completely eliminated by the relaxation; compression residual stress of the machined surface is changed gradually to tensile stress during the relaxation. These research results are very helpful to the application of nano-machined parts.
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Ogar, P. M., and D. B. Gorokhov. "Influence of Materials Hardenability Parameters on the Machine Parts Characteristics after Unloading." Key Engineering Materials 723 (December 2016): 369–75. http://dx.doi.org/10.4028/www.scientific.net/kem.723.369.
Повний текст джерелаАнотація:
This paper studies the problem of the relative area changing on a decrease of the load applied to the joint of roughness surfaces. The penetration of a rigid rough sphere (indenter) into the elastic hardenable half-space is initially considered, then the elastic crater restoring by unloading is considered. To defining elastic-plastic material, Hollomon’s power law is used. To describe a contact of a rigid rough surface with an elastic plastic half-space, the discrete model of a rough surface is used. Microasperities are represented as a set of identical spherical segments, the height distribution of which corresponds to the bearing profile curve of the real surface. The dependence the dimensionless force elastic-geometric parameter Fq on a relative amount of indentation ε at loading and the dependence of analogous parameter Fqe on amount of ε-Dε at unloading are obtained. The relations of relative contact areas h and he on dimensionless loading Fq and Fqe at loading and unloading for different values of a hardening exponent n and parameter are given. The obtained results are of practical importance for the performance prediction of fixed machine elements’ joints at the design stage, in particular for tightness supply of flange couplings and high pressure vessels seals.
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Istomin, A. B., I. V. Lizunov, V. O. Dmitriev, and V. B. Kozlov. "Methods of restoring parts in repairs." Glavnyj mekhanik (Chief Mechanic), no. 6 (May 25, 2021): 59–73. http://dx.doi.org/10.33920/pro-2-2106-05.
Повний текст джерелаАнотація:
The article presents the review of the main methods of restoration and repair of machine parts: mechanical and bench work, welding, surfacing, metal coating, chrome plating, nickel plating, steeling (iron plating), bonding, hardening the surface of parts and restoring their shape under pressure. The areas of application of each method, its advantages and disadvantages are noted. Welding and surfacing are used to restore more than half of all repaired car parts. With the help of welding, cracks and fractures on the frame and platform are repaired, patches, various overlays and reinforcing gussets are put, and the crankcases of the units are restored. Damaged or worn threads on stub axles and other parts are restored by welding, followed by cutting a new thread. The internal threads are restored in the same way. Restoration of parts by surfacing consists in surfacing the worn working surfaces in such a way that they can be processed to the nominal or repair dimensions. When repairing cars, automatic and semi-automatic surfacing and welding under a layer of flux or in a carbon dioxide environment are used. Damaged and worn parts can be repaired by pressure. This method is based on the use of the ductility of metals. The parts are restored to their nominal dimensions with the help of special devices, by moving a part of the metal from non-working areas of the part to its worn surfaces. When restoring parts by pressure, not only their external shape changes, but also the structure and mechanical properties of the metal. Plastics are used to restore worn parts when repairing metal-cutting machines. As an adhesive, plastics are widely used for bonding broken parts, as well as for obtaining a fixed connection of parts made of metallic and non-metallic materials. When repairing metal-cutting machines, the most widely used plastics are textolite, wood laminated plastics and fast-hardening plastic — styracryl.
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Gurey, Volodymyr, and Ihor Kuzio. "Mathematical model of dynamic processes during frictional hardening of the cylindrical surfaces of parts." Scientific journal of the Ternopil national technical university 100, no. 4 (2020): 29–39. http://dx.doi.org/10.33108/visnyk_tntu2020.04.029.
Повний текст джерелаАнотація:
The mathematical model of the elastic machine system has been developed, and describes the dynamic processes that occur during the frictional hardening of cylindrical surfaces of parts using a tool with transverse grooves on its working part, which forms a surface hardened metal layer with nanocrystalline structure. Transverse grooves on the working part of the tool increase the intensity of deformation of the surface layer in the contact area of the tool-part and the oscillating processes of the system. Differential equations that describe this process are based on Lagrange equations of the second kind. Based on the solution of the model’s the systems of equations, it is possible to determine the velocity and magnitude of displacement of a special device with autonomous drive of the tool, tool and treatment part during machining, reaction of device supports and spindle unit.
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Pastukhov, A. G., and O. A. Sharaya. "Cases of application of the installation for electromechanical processing in the hardening of machine parts." Glavnyj mekhanik (Chief Mechanic), no. 1 (January 25, 2021): 38–45. http://dx.doi.org/10.33920/pro-2-2101-05.
Повний текст джерелаАнотація:
The paper presents the cases of using the UEMO-standard installation based on the 1M63F101 screw-cutting lathe for electromechanical hardening of the working surfaces of agricultural machinery and equipment parts. According to the results of hardening of the spider ends of the cardan joints crosses of the tractor Belarus 82.1/102.1, plunger of milk homogenizer A1-ОG2М and disc coulters of the seeder SZT-3,6A, operational properties of the working surfaces of the said parts increased 1,5…2,0 times. To ensure the processing of parts of various shapes, the tooling for installing, positioning and fixing parts on basic equipment has been developed. Technical solutions of the tooling are protected by patents.
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Kovalevskyу, S., О. Kovalevska, and Yu Lupa. "IMPROVING THE PERFORMANCE CHARACTERISTICS OF MACHINE PARTS BASED ON THE COMBINED INFLUENCE OF STRONG MAGNETIC FIELDS." Collection of scholarly papers of Dniprovsk State Technical University (Technical Sciences) 2, no. 39 (December 21, 2021): 42–50. http://dx.doi.org/10.31319/2519-2884.39.2021.5.
Повний текст джерелаАнотація:
Magnetic treatment is a promising method of hardening. Metal exposed to alternating magnetic fields changes the performance properties of the surface layer of a combination of magnetic and ultrasonic effects, provides a combined method of processing and strengthening surfaces of machine parts, which eliminates the main disadvantages of magnetic and electrical hardening — instability of physical and mechanical properties of this layer with detail.
The purpose of the work is to investigate the possibility of improving the performance of machine parts based on the combined effect of strong magnetic fields.
The study of the use of a uniform flux of magnetic fields generated by powerful permanent magnets was performed to affect the material volume of non-grinding plates of the cutting tool CNMG_120508E-M. The effect of uniform magnetic flux is initiated as a result of resonant oscillations of the sample caused by broadband exposure of equal amplitude by means of a "white noise" generator and a piezo emitter.
The authors found that as a result of volumetric strengthening of non-grinding plates of carbide cutting tools, by exposure to polyfrequency oscillations in the form of a broadband frequency spectrum of equal amplitudes, a significant reduction in dimensional wear of the plates is achieved. Adding mechanical vibrations to the samples in a uniform constant magnetic field allowed to achieve volumetric hardening of the samples from 150 HB to 240 ÷ 250 HB, ie 60 ÷ 65% in 10—12 minutes, which is the hardening of the samples by 5—6% in one minute.
The work on determining the relationship of changing properties with processing time, frequency range, amplitude and other modes to find the optimal values of processing parameters, has great prospects for the ability to obtain a set of performance characteristics, control external and internal properties of products.
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Burlachenko, O. V., V. N. Zlobin, and A. O. Burlachenko. "Technical Support for the Health of the Reducers of Construction Machines on the Basis of Application Device for the Application of Hard Coatings." Materials Science Forum 945 (February 2019): 724–28. http://dx.doi.org/10.4028/www.scientific.net/msf.945.724.
Повний текст джерелаАнотація:
The new technology of ensuring efficiency of reducers of construction machines is offered. The technology is based on the application of hardening coatings on the contact surface of the gear teeth. To implement the method, the authors developed an installation for applying hardening coatings by ion implantation. Similar devices used for the application of hard materials in the form of diffusion coatings on hot parts of tooling and machine parts are described. It is shown that the proposed installation has a greater technical and economic efficiency compared to existing analogues. The description of the design and operating principle of the proposed device is presented. The results of experimental researches of efficiency of the offered technology are presented. The modes of processing allowing to achieve the maximum indexes of working capacity are picked up. The conducted researches have shown the efficiency of the offered technology for the details from hard alloys.
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Kogan, Ya D. "Research of Lakhtin’s school on advanced processes of surface hardening of machine parts and tools." Metal Science and Heat Treatment 52, no. 5-6 (November 2010): 195–203. http://dx.doi.org/10.1007/s11041-010-9264-z.
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Kirichek, Andrei, Oleg Fedonin, Dmitry Solovyov, and Svetlana Fedonina. "Expanding Technological Capabilities of The Combined Hardening of Steel by Deformation." MATEC Web of Conferences 297 (2019): 05004. http://dx.doi.org/10.1051/matecconf/201929705004.
Повний текст джерелаАнотація:
The technology of wave deformation hardening of metal machine parts is described, which allows obtaining a hardened surface layer up to 10 mm deep. The article presents the results of studying the microstructure and hardness of the samples strengthened as a result of chemical heat treatment and combined hardening consisting of preliminary wave deformation hardening and subsequent chemical heat treatment of structural alloyed steel 15CrС2Ni2Mg. It is established that a preliminary impact on the cemented material by a deformation wave contributes to creating uniformly high packing density of martensite, as well as smaller sizes of martensite needles in the subsurface layer and at the border of the cemented layer, in the core of the sample and contributes to the absence of large-needle martensite. Applying this technology allows forming a high uniform hardness at 65 HRC at a depth of 1.5 mm, with its gradual reduction to the core of the sample, while maintaining a high level of toughness. The results obtained allow recommending wave deformation hardening and the combined technology based on it to improve the performance properties of variable machine parts that operate under the conditions of sliding friction and impact loads.
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Levashova, Elena, Nikolai Ababkov, and Maksim Pimonov. "Influence of the Method of Strengthening the Surface of Parts on Acoustic Characteristics." MATEC Web of Conferences 297 (2019): 05010. http://dx.doi.org/10.1051/matecconf/201929705010.
Повний текст джерелаАнотація:
The article is devoted to the consideration of the method of increasing the mechanical and tribological properties of parts of mining machines due to quenching and electric arc hardening of the restored surface layer by welding. The essence of the proposed method was to restore the geometric dimensions of the part with cored wire with guaranteed hardness of 50-55 HRC and an increase in values up to 60 HRC due to electric arc hardening (EAH), which uses equipment available at each mining enterprise, namely, a tungsten-electrode torch cooled water and protective gas. Argon, which has a relatively low ionization potential, was used as a protective gas, and the use of carbon dioxide was not considered, owing to the increased tendency to crack formation of layers strengthened in this way. The results of studies of the acoustic characteristics of the restored part of the rotation of the welding, made of steel 30HGSA in the initial state of surfacing after electric arc hardening, after quenching and the combined combination of hardening and electric arc hardening are shown.
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Skeeba, Vadim, and Vladimir Ivancivsky. "Improving the efficiency of surface-thermal hardening of machine parts in conditions of combination of processing technologies, integrated on a single machine tool base." Metal Working and Material Science 23, no. 3 (September 15, 2021): 45–71. http://dx.doi.org/10.17212/1994-6309-2021-23.3-45-71.
Повний текст джерелаАнотація:
Introduction. In the manufacturing industry, there is a particular interest in the development of a new type of technological equipment, which makes it possible to implement methods for modifying the parts surface layers 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 neutralize the disadvantages of monotechnologies and obtain new effects that are unattainable when using technologies separately. The use of hybrid machine tools in conjunction with the developed technological recommendations will allow achieving a multiple increase in the technical and economic efficiency of production, resource and energy saving, which in turn will contribute to an increase in the competitiveness of products and the renewal of the technological paradigm. Purpose of work: increasing productivity and reducing energy consumption during surface-thermal hardening of machine parts by exposure to concentrated energy sources under conditions of integrated processing. Theory and methods: studies of the possible structural composition and layout of hybrid equipment during the integration of mechanical and surface-thermal processes are carried out taking into account the main provisions of structural synthesis and the components of metalworking systems. Theoretical studies are carried out using the basic provisions of system analysis, geometric theory of surface formation, design of metalworking machines, finite-element method, mathematical and computer simulation. Mathematical simulation of thermal fields and structural-phase transformations in the case of HEH HFC is carried out in the ANSYS and SYSWELD software packages, using numerical methods for solving the differential equations of unsteady thermal conductivity (Fourier's equation), carbon diffusion (Fick's second law), and elastoplastic behavior of the material. The verification of the simulation results is carried out by conducting field experiments using: optical and scanning microscopy; mechanical and X-ray methods for determining residual stresses. In the study, Uone JD520 and Form Talysurf Series 2 profilograph-profilometers are used to simultaneously measure shape deviations, waviness and surface roughness. Surface topography is assessed using a Zygo New View 7300 laser profilograph-profilometer. The microhardness of the hardened surface layer of parts is evaluated on a Wolpert Group 402MVD device. Results and discussion. An original method of structural-kinematic analysis for pre-design research of hybrid metalworking equipment is presented. Methodological recommendations are developed for the modernization of metal-cutting machine tools, the implementation of which will allow the implementation of high-energy heating by high-frequency currents (HEH HFC) on a standard machine-tool system and ensure the formation of high-tech technological equipment with expanded functionality. A unified integral parameter of the temperature-time effect on a structural material is proposed when the modes of hardening by concentrated heating sources are assigned, which guarantee the required set of quality indicators of the surface layer of machine parts, while ensuring energy efficiency and processing productivity in general. It is experimentally confirmed that the introduction into production of the proposed hybrid machine tool in conjunction with the developed recommendations for the purpose of the HEH HFC modes in the conditions of integral processing of a “Plunger bushing” type part in relation to the factory technology allows increasing the productivity of surface hardening by 3.5 ... 4.1 times, and reduce energy consumption by 9.5 ... 11.3 times.
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Safin, Eduard Vilardovich, and Anatoliy Mikhailovich Smyslov. "Peculiarities of Quality Ensuring in Parts from Ti-Based Alloy VT6 with Ultrafine-Grained Structure." Key Engineering Materials 684 (February 2016): 440–44. http://dx.doi.org/10.4028/www.scientific.net/kem.684.440.
Повний текст джерелаАнотація:
The work analyzes application perspectives of Ti-based alloy VT6 (Ti-6Al-4V) with an ultrafine-grained structure with different grain sizes as structural material to produce high-load machine parts. The paper considers technological factors for ensuring quality of parts with account of assumed conditions of their exploitation, differently directed change of mechanical properties with reduction of an average grain size and choice of surface hardening technique.
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Kostyk, Kateryna. "DEVELOPMENT OF INNOVATIVE METHOD OF STEEL SURFACE HARDENING BY A COMBINED CHEMICAL-THERMAL TREATMENT." EUREKA: Physics and Engineering 6 (November 30, 2016): 46–52. http://dx.doi.org/10.21303/2461-4262.2016.00220.
Повний текст джерелаАнотація:
The aim of the article is a hardening of the surface steel layers due to the combination treatment. Samples of steel 38Cr2MoAl were hardened by complex chemical and thermal treatment such as carburizing and subsequent boriding. It was established that surface double-layer hardening for steel 38Cr2MoAl with sequential saturation with atomic carbon (during carburizing) and atomic boron (during furnace boriding) at different temperatures allowed to form a boride layer with transition zone. The obtaining transition zone can improve operational properties of machine parts and tools by micro-friability reduction of diffusion layer. An optimal mode of complex chemical-thermal treatment (CTT) was obtained for the regime, which includes carburizing at 950 °C for 2 hours, boriding at 950 °C for 2 hours, which allows to get the best value for the surface hardness of 22 GPa with a maximum overall diffusion layer 1.4 mm. Due to the technology of combined treatment we can significantly reduce treatment time compared to traditional hardening means and significantly improve product performance properties due to the transition zone between the borides and the matrix of machine elements. The technology can be used in enterprises where there is any hardening furnace without additional installation or conversion of equipment.
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Gurey, Volodymyr, Vitaliy Korendiy, and Ihor Kuzio. "Simulation modelling of dynamic processes due discontinuous frictional treatment of the flat surfaces." Ukrainian Journal of Mechanical Engineering and Materials Science 6, no. 2 (2020): 23–33. http://dx.doi.org/10.23939/ujmems2020.02.023.
Повний текст джерелаАнотація:
Friction treatment refers to surface strengthening (hardening) methods using highly concentrated energy sources. In the course of this processing in the surface layers of the processed surfaces of parts the strengthened layer with nanocrystalline structure is formed. The formed layer has specific physical, mechanical, chemical properties, as well as improved performance properties, which are significantly different from the base metal. A highly concentrated energy source is formed in the contact area of the tool-part due to the high-speed friction (60–90 m/s) of the tool on the treatment surface. Frictional treatment of flat parts according to the kinematics of the process is similar to grinding. The strengthening process was carried out on an upgraded surface grinder. The tool is a metal disk made of stainless-steel. Transverse grooves are formed on the working surface of the tool to intensify the process of forming a strengthened (reinforced) layer with a nanocrystalline structure. The grooves form additional shock loads in the contact area of the tool-treatment surface of the part. These shock loads increase the shear deformation of the metal of the parts’ surface during treatment, which affects into formation the quality parameters of the parts’ surface and surface layer. To study the friction treatment process, the calculation scheme of the elastic system of the machine was developed. A simulation model for the study of dynamic processes that take place during the friction treatment of flat surfaces was built. This model gives possibility to determine the displacements and velocities of the machine table on which the part is fixed and the tool, and to determine their mutual displacement and also calculate the reaction of the machine table.
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Panteleyenko, Fedor, Oleg Ostanin, Katerina Panteleyenko, and Grigory Petrishin. "New Boron-Containing Materials for Surface Hardening." MATEC Web of Conferences 297 (2019): 05011. http://dx.doi.org/10.1051/matecconf/201929705011.
Повний текст джерелаАнотація:
The authors propose the range of new materials for restoring and strengthening coatings deposition, which have the next advantages: they are made of dispersive metal wastes (allows solve the problem of waste recycling), inexpensive, doesn’t require special equipment and expensive expendables, provides high adhesion to the steel underlay, high wear resistance and low porosity. The microstructure and the main regularities in coatings obtained of these new materials via different methods are researched and described in this paper. Based on this, the main recommendations in applying area for these coatings can be formulated. Industrial testing of such coatings confirmed their high exploitation properties. New materials can be applied for restoring and strengthening of metallurgical equipment, agricultural tillage and forage machines, elements of constructing machines metal parts.
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Ciuplys, Antanas, and Valdas Kvedaras. "Peculiarities of Fatigue Fracture of Steel Hardened by Various Surface Treatments." Key Engineering Materials 527 (November 2012): 107–12. http://dx.doi.org/10.4028/www.scientific.net/kem.527.107.
Повний текст джерелаАнотація:
Fatigue strength is one of the most important mechanical properties. Durability and reliability of car parts is often defined by their fatigue strength, since most of them are loaded with dynamic, repeating or variable loads and the main type of failure is metal fatigue. Fatigue crack usually starts on the metal surface. The interrelationship of the surface layer together with the characteristics of internal metal volume determine the value of fatigue limit and the coefficient level of stresses’ intensity, which is required for the start of fatigue crack. Various hardening methods of surface have a huge impact on fatigue strength of structural materials. The choice of surface processing method is determined by properties and microstructure of a material, as well as the purpose and working conditions of part’s material. Very often the optimum processing is a combination of several methods, which enables to obtain the required properties (high fatigue strength, wear, etc.). Hardening with high-frequency electric current (HfEC) is widely used process for the surface hardening of steel. The components are heated by means of an alternating magnetic field to a temperature within or above the transformation range followed by immediate quenching. The core of the component remains unaffected by the treatment and its physical properties are those of the bar from which it was machined. Investigation of specific fatigue fracture properties enables to determine the kinetic of processes, related with fatigue crack initiation and propagation. Analysing fractures of machine parts and comparing them with the most specific “mode” fractures it is possible to determine the nature of affecting loads and the reason of part failure. The impact of several combined surfaces processing on the fatigue strength and fractures of carbon steel samples is investigated in the work. The surface was hardened using different processing combinations: by hardening with high frequency electricity currents, rolling by rollers, heating and cooling under different temperatures. Experimentally it was proved that thermal treatment of plastically deformed carbon steel significantly increases fatigue strength. After surface hardening with the given regimes, the microstructure and residual stresses are formed in such way that fatigue crack begins to grow under the hardened sample surface. Samples, in which the fatigue crack initiates inside the sample, have higher fatigue strength than the samples, the fatigue crack of which initiates on the surface.
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Al-Tibbi, Wisam. "Optimal electroacoustic coating modes investigation for production of nanostructured materials." E3S Web of Conferences 273 (2021): 04001. http://dx.doi.org/10.1051/e3sconf/202127304001.
Повний текст джерелаАнотація:
Described the research results of hardening coatings coating modes influence on the microstructure of the surface layer of machine parts. Electroacoustic coating was used as a coating method. X-ray structural analysis and electron microscopy were used to investigate the microstructure of the coatings. The results obtained can be used to determine the optimal technological modes of coating.
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Shepelyakovskiil, K. Z. "Bulk-surface hardening as a method for increasing strength, reliability, and service life of machine parts." Metal Science and Heat Treatment 37, no. 11 (November 1995): 433–40. http://dx.doi.org/10.1007/bf01154216.
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Glushko, S. P. "Investigation of the electrospark coating, alloying and strengthening technology." Advanced Engineering Research 21, no. 3 (October 18, 2021): 253–59. http://dx.doi.org/10.23947/2687-1653-2021-21-3-253-259.
Повний текст джерелаАнотація:
Introduction. The work objectives were the analysis and application of the technology of electrospark deposition of wear-resistant metal coatings on cutting tools or machine parts for their hardening or dimensional restoration.Materials and Methods. The technology, device and principle of operation of the modernized installation intended for electric spark application of wear-resistant metal coatings with composites T15K6, VK8 and VK6 are considered.Results. To determine the parameters of the upgraded electrospark alloying plant, experiments were carried out on hardening of polished samples made of steel 45 with hard alloy T15K6 with dimensions of 25×25×25 mm. As a result of using the experiment planning method, the possibility of selecting and adjusting the installation parameters was confirmed. The following parameters were selected for hardening samples made of steel 45 with hard alloy T15K6: current I = 1-2–A, voltage U = 40-75 V, capacitor bank capacity = 60–100 µF.Discussion and Conclusions. The use of carbon dioxide as a protective medium enables to increase the number of passes and, accordingly, the number of coating layers to twenty, to obtain a total thickness of up to 0.3 mm with a dense structure without oxides. Coatings of this thickness make it possible not only to strengthen, but also to restore the dimensions of worn machine parts. The parameters of the technological modes of electrospark alloying significantly affect the intensity of coating application and the quality of the resulting surface. A rise in the electrical parameters causes an increase in the intensity of each individual discharge and, within certain limits, contributes to an increase in the amount of the transferred coating material, as well as to deeper transformations of the coated surface in the discharge zone. Thus, an electrospark alloying plant equipped with monitoring and diagnostic tools, as well as with a protective gas supply system, can be used for hardening and restoring machine parts and cutting tools.
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Yang, Hong Cai, and Ming Qing Wu. "Machined Surface Quality Improvement Measures Affecting Factors and Research." Applied Mechanics and Materials 496-500 (January 2014): 516–19. http://dx.doi.org/10.4028/www.scientific.net/amm.496-500.516.
Повний текст джерелаАнотація:
The use of mechanical products to improve performance and increase the service life of components and composition of the product processing quality is closely related to machining quality is the basis of product quality assurance. Measure of good or bad quality parts machining the main indicators are: machining accuracy and surface roughness. This paper mainly affect parts of the surface roughness factor, parts of the surface layer of the physical and mechanical properties (surface work hardening, residual stress, microstructure change and grinding burn), surface quality performance parts and other factors affecting the analysis and research to improve the quality of machined surface process measures.
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Sidhom, Habib, Naoufel Ben Moussa, Brahim Ben Fathallah, Naziha Sidhom, and Chedly Braham. "Effect of Surface Properties on the Fatigue Life of Manufactured Parts: Experimental Analysis and Multi-Axial Criteria." Advanced Materials Research 996 (August 2014): 715–21. http://dx.doi.org/10.4028/www.scientific.net/amr.996.715.
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The effects of machined and treated surface characteristics on the fatigue strength were analyzed on the basis of experimental results related to AISI D2 ground surface and AA 5083-H111 hammered surface. The fatigue strength improvement resulting from controlled grinding and mechanical surface treatment was discussed on the basis of the beneficial effect of the work hardening and the stabilized residual stress. A numerical procedure using F.E.M for calculating residual stress and work hardening evolution under cyclic loading has been developed. The validation of the numerical procedure was carried out by comparing the calculated residual stress profiles to those resulted from XRD measurements. The multi-axial criterion accounting for the work hardening and the residual stress was used to predict the fatigue life of notched samples.
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Kostyk, Kateryna, Michal Hatala, Viktoriia Kostyk, Vitalii Ivanov, Ivan Pavlenko, and Darina Duplakova. "Simulation of Diffusion Processes in Chemical and Thermal Processing of Machine Parts." Processes 9, no. 4 (April 15, 2021): 698. http://dx.doi.org/10.3390/pr9040698.
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To solve a number of technological issues, it is advisable to use mathematical modeling, which will allow us to obtain the dependences of the influence of the technological parameters of chemical and thermal treatment processes on forming the depth of the diffusion layers of steels and alloys. The paper presents mathematical modeling of diffusion processes based on the existing chemical and thermal treatment of steel parts. Mathematical modeling is considered on the example of 38Cr2MoAl steel after gas nitriding. The gas nitriding technology was carried out at different temperatures for a duration of 20, 50, and 80 h in the SSHAM-12.12/7 electric furnace. When modeling the diffusion processes of surface hardening of parts in general, providing a specifically given distribution of nitrogen concentration over the diffusion layer’s depth from the product’s surface was solved. The model of the diffusion stage is used under the following assumptions: The diffusion coefficient of the saturating element primarily depends on temperature changes; the metal surface is instantly saturated to equilibrium concentrations with the saturating atmosphere; the surface layer and the entire product are heated unevenly, that is, the product temperature is a function of time and coordinates. Having satisfied the limit, initial, and boundary conditions, the temperature distribution equations over the diffusion layer’s depth were obtained. The final determination of the temperature was solved by an iterative method. Mathematical modeling allowed us to get functional dependencies for calculating the temperature distribution over the depth of the layer and studying the influence of various factors on the body’s temperature state of the body.
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Skeeba, Vadim, Vladimir Ivancivsky, and Egor A. Zverev. "Features of the Structure Formation of the Machine Parts’ Surface Layer in the Conditions of Hybrid Processing." Key Engineering Materials 909 (February 4, 2022): 87–93. http://dx.doi.org/10.4028/p-4wh693.
Повний текст джерелаАнотація:
The object of these studies is the machine parts manufacturing process consisting of the following operations: pre-machining (rough and semi-finishing turning), surface hardening (high-energy heating by high-frequency currents) and finishing machining (finishing turning and diamond smoothing). We present the solution to the problem of quality forecasting in the conceptual design of hybrid process equipment. The developed methodology for substantiating the technical characteristics of machine tools based on mathematical simulation of its operating conditions provides the possibility of using automatic design systems at the initial stage of creating a general concept. We tested the developed design methodology and proposed a scheme for the implementation of hybrid metalworking process equipment based on the lathes. It is experimentally established that under the conditions of the developed hybrid processing it becomes possible to increase the surface microhardness of parts by 12-17 % and to increase the level of compressive residual stresses in the surface layer by 10-21 %.
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Yang, Wen Jie, Su Yu Wang, Yuan Chao Du, and Lin Lin Ma. "Analysis of Surface Morphology in Work Hardening of High-Speed Milling Based on Dislocation Theory." Applied Mechanics and Materials 373-375 (August 2013): 2015–18. http://dx.doi.org/10.4028/www.scientific.net/amm.373-375.2015.
Повний текст джерелаАнотація:
Work hardening is an important index for the evaluation of the machined surface quality in high-speed milling. The morphology of work hardening can be visually observed by the metallographic pictures of high-speed milling gained from the scanning electron microscope which includes the lattice distortion and cracks etc. Forming mechanism of lattice distortion and micro crack of micro morphology under the workpiece surface is analyzed according to the dislocation theory; meanwhile, the effects on surface quality of the microstructure of the work hardening layer are discussed, which have important guiding significances on improving the surface quality and prolonging the service life of the parts.
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Savaria, Vincent, Florent Bridier, and Philippe Bocher. "Measuring in-depth Residual Stress Gradients: The Challenge of Induction Hardened Parts." Materials Science Forum 768-769 (September 2013): 158–65. http://dx.doi.org/10.4028/www.scientific.net/msf.768-769.158.
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Highly stressed machine parts such as gears and shafts are often surface treated to increase wear and fatigue resistance at critical locations. For example, induction surface hardening (ISH) is increasingly used in the automotive and aerospace industries thanks to the availability of modern multiple frequencies generators and complex shaped coils that provide a great flexibility in process control. With similar end-results in terms of hardened depths, very different residual stress profiles may be obtained, and optimized by modifying both heating and quenching kinetics. If hardness and microstructures variations are routinely verified, some challenges raise for the measurement of the residual stress gradients within complex geometry parts, in particular for the case of deep hardened layers. The most commonly used technique is X-ray diffraction (XRD). It requires using successive layer removal to get access to in-depth stresses. The measurements must therefore be corrected for the stress redistribution occurring during layer removal. However, industrial geometries are often not covered by traditional correction methods. The present work aims at applying XRD to precisely measure in-depth residual stress profiles in induction hardened thin discs made of martensitic steel. Both issues of microstructural variations and redistribution of stresses during layer removal are tackled. First, X-ray elastic constants were determined experimentally using a miniature custom-made tensile machine with specimens heat treated to simulate different microstructures found in ISH parts. Second, a recently introduced finite elements based layer removal correction method was applied. The proposed methodology is used to show the impact of preheating and core hardness on the residual stresses obtained after induction hardening.
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Malikov, Vladimir, Alexey Ishkov, Anatoly Sagalakov, and Sergey Dmitriev. "Research of structure and properties of boride hardening coatings." MATEC Web of Conferences 265 (2019): 01014. http://dx.doi.org/10.1051/matecconf/201926501014.
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High strength aluminum alloys are particularly suitable as lightweight materials in vehicle and aircraft engineering. The wear resistance of materials can be improved by surface and coating technology. Strengthening of parts and units of machines, increased reliability and longer service life is an important task of modern industry. The aim of research was to apply boride coatings on surface of steel parts. Timeliness is subject to necessity to harden surface of steel used in high-load conditions. Samples of coatings on 65 G grade steel, applied by HFC-heating, were obtained. Research of samples with different coatings by means of metallurgical microscope was carried out. Data on samples with different coatings research by means of an eddy current measuring system was obtained and conclusion on electrical conductivity distribution along the sample surface depending on flux quantitative content during boriding was made.
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Соловьёв, Д., D. Solovev, Андрей Киричек, Andrey Kirichek, Дмитрий Тарасов, and Dmitriy Tarasov. "MACHINERY LIFE INCREASE BY COMBINED STRENGTHENING." Bulletin of Bryansk state technical university 2016, no. 2 (June 30, 2016): 52–58. http://dx.doi.org/10.12737/20244.
Повний текст джерелаАнотація:
The reason of failure of many machine parts is contact fatigue. To increase contact-fatigue wear resistance it is necessary to create a surface layer possessing increased stress-strain properties which are formed by strengthening. The most effective methods of strengthening are those creating a surface layer with simultaneous high hardness and large reserve of plasticity. One of such methods is combined strengthening at which a surface to be strengthened is affected preliminarily by deformation shock waves forming a deep work-hardened layer and then its case hardening is carried out. As a result of this process a strengthened surface layer is formed which consists of hard uniformly strengthened carburized layer and a softer heterogeneously strengthened sublayer alternating hard and soft areas depending on streng-thening modes with shock waves. The operational researches of samples obtained by the offered combined strengthening have shown high efficiency of the method for life increase under conditions of contact cyclic loads which can increase considerably a range of machine parts to be strengthened.
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Gorlenko, A. O., S. V. Davydov, M. Yu Shevtsov, and D. A. Boldyrev. "Wear-Resistance Increase of Friction Surfaces of Steel Machine Parts by Electro-Mechanical Hardening." Steel in Translation 49, no. 11 (November 2019): 800–805. http://dx.doi.org/10.3103/s0967091219110044.
Повний текст джерела
50
Yang, Xin Chun, and Hong Jun Wang. "Investigation of Precipitated Hardening Layer Performance on Machined NAK80 Steel Surface." Materials Science Forum 704-705 (December 2011): 1219–22. http://dx.doi.org/10.4028/www.scientific.net/msf.704-705.1219.
Повний текст джерелаАнотація:
The surface integrity of NAK80 steel by grinding and electrical discharge machining (EDM) was studied in this paper. Microhardness, 3D topography and surface roughness of machined surface precipitation hardening layer were measured respectively. And the residual stress of the machined steel surface was measured with X-ray diffraction. Further experiments indicated that, compared with EDM, grinding method can obtain better surface integrity, and lower stress concentration sensitivity of NAK80 steel. But when machining the parts with complex shapes, EDM has the unparalleled advantages to grinding method.