Surface Layer Of Machine Parts Research Articles

FEATURES OF THE FORMATION OF THE NANOSTRUCTURAL STATE OF THE SURFACE LAYER OF STEEL PARTS DURING PROCESSING AND OPERATION

Considered patterns of formation of the nanostructural state of the surface layer of machine parts during friction under conditions of complex dynamic loading. The results of the complex assessment of the state of the surface layer of samples after friction continuous indentation and scanning methods indenter, an analysis of changes in the work function of the electron from the surface of the samples. Shown that during the friction of steel surfaces, an increase in transverse slippage contributes to the formation of a more uniform surface layer. This decreases its strength, wear resistance, and a more uniform surface microgeometry. This is accompanied by a decrease in the magnitude and spread of the electron work function over the surface. The relationship between the nanostructural state of a polished surface and roughness and reflectivity is presented.

REFINEMENT OF THE PARAMETRIC MODEL OF ROUGHNESS FORMATION BY CONDUCTING AN EXPERIMENT

The article deals with the influence of lubricating and cooling technological medium and cutting temperature regime on the efficiency of the cutting process. The article presents the results of experimental studies, which showed that the use of optimal lubricant and cutting temperature control allows to increase the efficiency of the cutting process in the following directions:– Increase of tool durability. The application of coolant allows to reduce the temperature in the cutting zone, which leads to a decrease in tool wear.– Reduction of roughness of the machined surface. The use of coolants allows to reduce the temperature in the cutting zone, which leads to a decrease in the deformation of the machined material and, as a consequence, to an improvement in the quality of the machined surface.– Reduction of cutting forces. The application of coolants allows to reduce the temperature in the cutting zone, which leads to a decrease in friction between the tool and the processed material and, as a consequence, to a decrease in cutting forces.The obtained results indicate that the use of optimal coolant and cutting temperature control are effective ways to improve the efficiency of the cutting process.Recommendations on the use of coolants (lubricating and cooling liquids) and types of coolants to improve the accuracy of the surface layer of machine parts; Recommendations on the creation of new types of environmentally friendly coolants are given.A multifaceted method of selecting new compositions of coolants is proposed. The method is based on the fact that the chemical composition of the part and tool material, machining methods, cutting modes, requirements to accuracy and quality of the surface layer of the part are taken into account when selecting coolants.

Оценка влияния параметров режима лазерной закалки на качество поверхности и поверхностного слоя деталей станков (обзор)

This review provides an assessment of the influence of the parameters of the laser hardening mode on the quality of the surface and the surface layer. It is presented how the processing speed, radiation power, surface heating temperature, initial structure during, the number of passes laser hardening affect the geometric parameters of the laser exposure zone, roughness, hardness and wear resistance of the surface, deformation, magnitude and sign of residual stresses in the surface layer. The conclusion is made in the form of recommendations on the selection of parameters of the laser hardening mode to obtain a given surface quality and surface layer of machine parts.

Effect of kinematics of working tool during surface plastic deformation on performance characteristics of reinforced parts

The article presents the results of experimental studies to determine the influence of the kinematics of the working tool during surface plastic deformation (SPD) on the operational properties of machine parts: wear resistance, corrosion resistance and flexural rigidity. As a result of experimental studies of the quality of the surface layer of machine parts, it was established that when hardened by surface plastic deformation with a toroidal roller with reverse circular motion, in comparison with a similar roller, but rotating relative to the central axis and with a roller that performs circular rotation relative to the central axis passing through the plane, connecting single-radius elements, wear resistance increases by 69,6 % and 29,8 %, the corrosion rate decreases by 53,0 % and 23,8 % and flexural stiffness increases by 58,0 % and 36,8 %, respectively.

Development of a Progressive Design of a Ground Centrifugal Pump

The processes and technologies of gas-flame surfacing of metal powders are considered, promising modern gas-thermal methods for creating a hardened surface layer of machine parts are established. The use of a specific surfacing method from the considered ones is due to the production conditions, the number, shape and size of the surfaced parts, the permissible share of the base metal in the surfaced, technical and economic indicators, and for restorative surfacing – the amount of wear. The choice of the type of deposited metal and, consequently, the grade of the filler material is made in accordance with the type of working loading of the deposited part. Therefore, when choosing the type of deposited metal, they focus on the prevailing type of wear. Based on the conducted studies of the gas-thermal method of applying wear-resistant coatings, a new design of the impeller of a centrifugal ground pump has been developed.

ABOUT THE WORK OF THE TECHNOLOGICAL SCIENTIFIC SCHOOL OF THE RYBINSK STATE AVIATION TECHNICAL UNIVERSITY NAMED AFTER P. A. SOLOVYOV IN THE FIELD OF HIGH-TECH AND PRODUCTION TECHNOLOGIES

The article presents the results of research carried out by the author independently, as well as jointly with his students (9 doctors and 60 candidates of technical sciences). Recommendations on technological support of the accuracy of processing and quality of the surface layer of machine parts are proposed, taking into account the technological conditions of processing (cutting mode, properties of the processed and tool materials, geometry of the cutting part of the tool), as well as indicators of the operational properties of machine parts and products in general, (fatigue strength, contact stiffness of the surfaces of parts and their wear resistance, corrosion resistance, as well as the strength of the press joints). The directions of automation of manufacturing technology and assembly of products, as well as the organization of production (calculation of the number of parts in a batch, justification of the choice of equipment, organization of joint parallel work of the designer and technologist, etc.), problematic issues of repair of high-tech products, including aviation gas turbine engines, and quality management of products and processes are proposed. The article is dedicated to the 40th anniversary of the Department of “Technology of Aircraft Engines and General Mechanical Engineering”, Rybinsk State Aviation Technical University named after P. A. Solovyov.

Effective combined surface hardening processes of structural steels using ultrasound

The effectiveness of hardening of the surface layer of machine parts is evaluated by the operational properties of the surface layer and depends on many conditions that characterize the specific features of the technological process in which this method of hardening is carried out. The surface plastic deformation of structural steels with the use of ultrasound is studied. Four variants of hardening are considered: ultrasonic treatment with continuous supply of ultrasonic energy, pulse ultrasonic treatment, combination of ultrasonic treatment with subsequent pulse treatment, ultrasonic treatment after hardening with induction heating. It is shown that ultrasonic treatment increases microhardness of surface layer of structural steels by 1.5 times, HF hardening by more than 2 times, HF hardening + UZO combination by 3 times and HF hardening + IUZO combination by 3.2 times. Ultrasonic treatment increases compression stresses occurring in steel surface hardened by HFI hardening. The compressive stresses increase especially strongly after pulse ultrasonic treatment with five passes and reach the value of 1200 Pa.

Intensification of stress state at deformation site under local action of a deformation tool

This paper discusses the development of a new procedure for finishing and hardening treatment by changing the kinematics of a deformation tool having a double-radius shape of the profile of the working surface, along with the determination of the stress-strain state in the site of elastic-plastic deformation and residual stresses in the hardened zone of the surface layer. The SOLIDWORKS 2018 software for 3D design and the ANSYS Work-bench 19.1 soft-ware using the finite element method were used to build a mathematical model of local loading. The temporary and residual stresses, the strain state in the loading zone, the depth of the plastic layer and the maximum value of the relative plastic deformation under various loading procedures of the working tool were determined. It was established that, at the reversible rotation of a double-radius roller, the values of temporary stresses are over 15% higher compared to those during static hardening, while the residual stresses are 5.7% higher. With the reversible rotation of the double-radius roll-er, the value of the maximum strain intensity becomes 2.11 times higher than that during static hardening. The intensity of the maximum residual stresses during the reverse rotation of the double-radius roller occurs at a depth 3 times greater than the indentation of the double-radius roller, rather than on the surface of the sample. The results of computer model-ling and numerical calculations indicate that the procedure of reversible rotation of a toroidal double-radius roller has the greatest influence on the intensity of the stress state in the deformation site, while the procedure of static hardening by a single-radius roller has the least impact. The obtained results suggest that the proposed technological process of surface plastic deformation based on the reversible rotation of the working tool will allow the radial tension to be reduced while maintaining the high quality of the surface layer of machine parts.

The choice of finishing methods and cutting modes in the development of technological operations based on the analysis of data on the quality of the surface layer

In the article, the authors conducted a brief review of the quality indicators of the surface layer of machine parts with various methods of abrasive processing. Recommendations are given on the choice of cutting modes during grinding, recommendations are also given on the refinement of grinding modes based on measurement data in real production conditions. The application of the approaches presented in the article may vary depending on the situation and the current production conditions, it is useful in the implementation of the educational process in the relevant specialized areas of training specialists in the development of course and diploma projects.

The effect of nanostructured coatings of cutting tools on the quality parameters of the surface layer of machine parts during turning, taking into account the action of volumetric heat sources and hardening of the processed material

The influence of the nanostructured coating of the cutting tool on the quality parameters of the surface layer of the workpiece is considered.

Повышение эффективности поверхностно-термического упрочнения деталей машин в условиях совмещения обрабатывающих технологий, интегрируемых на единой станочной базе

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.

Optimal electroacoustic coating modes investigation for production of nanostructured materials

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.

Laser Modification: Increasing the Wear Resistance of Friction Surfaces

The article deals with topical issues of studying the physical, mechanical and tribological parameters of the surface layer of machine parts subjected to laser processing. Various options for modifying mating surfaces are evaluated and analyzed. The data of microstructural analysis and indicators of wear resistance are presented. A theoretical model of the wear of heat-strengthened surfaces is proposed, explaining the mechanism for increasing their wear resistance as a result of homogenization of the microstructure of a special surface layer with increased bearing capacity. It is experimentally confirmed that the greatest wear resistance is observed in friction units during mutual modification of mating surfaces.

ТЕХНОЛОГИЯ КОМБИНИРОВАННОЙ ЭЛЕКТРОМЕХАНОУЛЬТРАЗВУКОВОЙ ОБРАБОТКИ ПОВЕРХНОСТНЫХ СЛОЕВ ДЕТАЛЕЙ МАШИН

The technology of combined electro–mechanical–acoustic treatment is presented, which is a combination of electro–mechanical treatment and surface plastic deformation by ultrasonic treatment. Microhardness and residual stresses in strengthened EMUzO surface layer of machine parts investigated.

Theoretical justifi cation for use of combined methods for hardening of surfaces of machine parts in order to control their fretting resistance

The theoretical justification for the hardening process of the surface layer of machine parts for combined methods of surface hardening with subsequent application of strengthening coatings, as well as reducing or increasing the fatigue limit due to the fretting process is presented.

Optimal Control of the Complex Process of Manufacturing Cylindrical Parts’ Printing Equipment

In the article is considered improvement of quality and performance properties of machines, mechanisms and processing equipment. The fail of service performance and the accelerated failure during operation usually are the result of processes that take place on the surface layers of parts.A significant place in solving these problems is given to the development of new technological processes design of equipment and rational choice of materials for their parts in order to ensure the necessary performance properties of the material from which they are made.One of the important directions of increasing the operational properties of the parts of printing equipment is to obtain the specified properties of the surfaces of the parts by methods of surface hardening.Increasing the operational properties is the combination of galvanic and chemical methods of coating with the simultaneous formation of regular microreliefs on the surface by methods finishing-strengthening treatment. Due to its high corrosion resistance and wear resistance, chromium coating is already used as a protective agent in many industries.When solving the problems of technological quality assurance of the parts' surface and operational properties it is necessary to provide the quality parameters of the surface layer of machine parts according to their purpose in order to predict the processing modes and determine the complex of processing methods that deliver the quality of the set of surface layer parameters with the highest productivity.For purposeful control of technological processes, an algorithm of complex technological process was developed on the basis of the analysis of the specified technological scheme for the calculation of geometric parameters in the case of partial-regular microrelief formation after vibration run-in and chrome plating. The automatic control system adds new features to printing equipment, making it possible to execute a large number of high-quality orders in short time.

On-line diagnostics of the physical and mechanical properties of the surface at the production stage

The article deals with the issues of increasing the efficiency of the formation of the performance of the surface layer of machine parts. The results of computer modeling of thermophysical processes in the cutting zone are presented. The possibility of controlling the process of formation of the surface layer structure on the basis of the measurement of the thermal EMF, which make up the cutting forces, as well as the vibro-acoustic signal is considered.

Numerical Simulation of Temperature Field in Steel under Action of Electron Beam Heating Source

It is impossible to improve the most critical performance properties of machine parts without methods of modifying the surface layer using such concentrated energy as laser, plasma, an electron beam or high-frequency currents. For the rational use of these methods, which are characterized by high heating rates, i.e. about 104 ... 105oC/sec a reliable mechanism for determining the processing modes that ensure the required level of quality characteristics of the hardened surface layer of machine parts, is essential. In this paper, the interrelation between the parameter values of thermal cycles, implemented in the surface layer of steel U8, and the modes of electron beam heating in the atmosphere has been determined.

Integrated Processing: Quality Assurance Procedure of the Surface Layer of Machine Parts during the Manufacturing Step "Diamond Smoothing"

The present study has found that during the integrated processing after the diamond smoothing, in the surface-hardened sample a cold-worked layer 0.01 ... 0.02 mm in thickness, the microhardness value of which reaches 868 HV, is formed. The intensity of compressive stresses on the part surface increases to στ = -678 MPa. The analysis of the experimental data has shown the relationship between the parameter Ra and the processing modes that can be used during diamond smoothing, based on the high performance and the desired surface roughness. It has been found that the minimum value of roughness Ra = 0.18±0.08 μm is reliably achieved by smoothing processing when the smoothing force Py ranges from 100 N to 150 N.

Влияние степени дискретного упрочнения поверхности на триботехнические характеристики сталей и сплавов

The development of modern aviation industry is impossible without improving the durability and reliability of the let-out products and reducing their consumption of materials and cost. While in service parts of aerospace and equipment most intense mechanical and thermal influences exposed surface layer of machine parts, failure of components in some cases due to the lack of resistance to surface abrasion. One effective way of solving this problem is the development and implementation of advanced methods of surface hardening, based on the local impact of highly concentrated energy sources, subordinate to the principle of discrete hardening. The authors propose to use the method of discrete laser hardening. Studies have shown that this method of surface hardening reduces friction and improves wear resistance.