Methods Of Surface Plastic Deformation Research Articles

An experimental and computational study of through-depth strain distribution during frictional treatment of a metastable austenitic steel

Frictional treatment, as a method of surface plastic deformation, forms a gradient hardened layer. In the case of metastable steels, this hardening is due, among other things, to the formation of strain-induced α'-martensite. The most reliable information about the thickness of this hardened layer can be obtained by measuring the hardness on transverse sections. This paper compares strain distribution through the depth of the hardened layer, obtained from layer-by-layer phase analysis and finite element modeling, with the data of durametric studies for the AISI 321 metastable steel subjected to frictional treatment under various loads on the indenter. A satisfactory coincidence of the distributions of the α'-phase concentration and hardness through the depth is observed only for the specimen subjected to frictional treatment at a maximum load of 400 N on the indenter. At the other loads on the indenter, the thickness of the layer containing α'-martensite is lower than the thickness of the hardened layer estimated from the durametric studies. In contrast, it is shown that, for all the loads applied to the indenter during frictional treatment, the through-depth distributions of the calculated values of equivalent plastic strain obtained from finite element modeling agree satisfactorily with the experimental hardness values.

ANTI-CORROSION PROTECTION OF PIPELINES

Currently, in our country, the issue of protecting metals from corrosion has achieved high results, so there is a big gap between the achievements of scientific research in this direction and their use in industry. It is necessary to develop and implement highly effective methods of increasing the strength, corrosion resistance, heat and cold resistance of metals and alloys. Popularization, dissemination and implementation of effective methods of protection against corrosion and corrosive-mechanical destruction of machines, devices, equipment and metal structures are of great importance.
 During surface-plastic deformation, a chip is not formed, but a fine plastic deformation of the surface layer takes place. As a result, the surface layer is strengthened, wear resistance and resistance to corrosive environment increases. In many cases, the use of surface-plastic deformation makes it possible to increase the safety margin of parts working under variable loads by 1.5 to 3 times, and to increase the service life of parts. The paper examines directions for increasing the stability of parts of oil industry equipment by the method of surface plastic deformation, for resistance against various types of corrosion and corrosive-mechanical destruction.
 Fatigue is the phenomenon of gradual accumulation of material damage under the action of variable loads, which leads to changes in the properties of crack formation, their development and destruction. The processes of metal fatigue have been studied by many researchers, many hypotheses have been put forward, but the nature of fatigue remains largely unexplained.

ELIMINATION OF CRACKS IN METAL PARTS

One of the most versatile and effective methods of restoring parts is the method of electric spark processing. On the basis of this method, a technological process was developed that allows to obtain a thick-layer coating of increased continuity. The use of electric spark processing in the restoration of parts is an urgent task of eliminating cracks in metal parts of machines. (Research purpose) The research purpose is eliminating cracks in metal parts of machines by the electric spark processing to obtain sealed coatings. (Materials and methods) BRKMTS3-1 bronze was chosen as the main electrodes, M1 copper was chosen for the reflow electrode for experimental work to eliminate cracks by electric spark treatment. It was determined that the process of eliminating cracks took place in several cycles. (Results and discussion) Experiments have shown that, using only the reception of a thick-layer electric spark coating, it is possible to close a crack up to 1.5 millimeters wide inclusive, but it is practically impossible to obtain a sealed coating. It was established as a result of studies of the effect of surface plastic treatment that the average microhardness of the coating, untreated by the method of surface plastic deformation, was 250 according to Vickers. The maximum microhardness of the sample treated by the method of surface plastic deformation at a depth of 0.05 millimeters was more than 500 Vickers. (Conclusions) The experiments carried out to eliminate cracks have shown that using only the reception of a thick-walled electric spark coating, it is easy to close a crack up to 1.5 millimeters wide inclusive, but it is almost impossible to obtain a sealed coating, since it has significant porosity. For those cases where the tightness of the seam is mandatory, additional processing by the method of surface plastic deformation is necessary.

RESEARCH OF SURFACE PLASTIC DEFORMATION UNDER HYDRO-IMPULSE INFLUENCE

Increasing requirements for modern machines necessitates the use of new equipment and the improvement of existing equipment. Methods and techniques aimed at improving its operational and quality characteristics. One of the areas of improvement is the method of surface plastic deformation, which qualitatively affects the overall reliability of the product. However, surface plastic deformation does not allow for the development of a schematic diagram and a general-purpose device that can be used to strengthen a wide range of agricultural machinery parts. Differences in the physical and mechanical properties of the materials of manufactured parts, their weight, dimensions, longitudinal and transverse stiffness, condition or position, hardening process, type of production and other factors in each specific case force designers and technologists to find reasonable options for designing new devices for processing parts by surface plastic deformation for ensuring high technical and economic indicators. Therefore, the development of surface plastic deformation devices and the improvement of existing equipment are urgent scientific and engineering tasks. The introduction of modern methods and tools in the development of mechanical engineering ensures an increase in the reliability of parts and products in general, as well as a reduction in the cost of production. This article describes the compaction of metal powders as a technological operation, as a result of which powder blanks are formed. The equipment for vibropressing of powder blanks is considered and compared. Technical processes of basic vibration and vibration impact are presented. The methods and schemes of implementation of vibropressing of powder materials are demonstrated. The classification of vibro-compaction processes according to the characteristics of vibration and vibration modes is analyzed.

Improved fretting fatigue mechanism of surface-strengthened Ti-6Al-4V alloy induced by ultrasonic surface rolling process

Surface plastic deformation methods are prevalently applied to improve the fretting fatigue (FF) property of titanium alloys. Understanding the intrinsic relation between surface plastic deformation severity and the FF property is of great significance to the application of these methods. Here, the influence of surface plastic deformation severity on the FF behavior of Ti-6Al-4V alloy is investigated. Two different levels of surface plastic deformation severity are prepared at the surface of Ti-6Al-4V alloy by employing ultrasonic surface rolling process. Uniaxial FF tests illustrate that both of the deformed samples have improved FF properties and although their fatigue life is comparable, the influences of their refined microstructures and compressive residual stresses are different. Pre- and post-mortem microstructural analyses reveals that the grains are coarsened or crystallized from amorphous material at the topmost surface under the multiaxial stresses to accommodate the plastic strain for the high surface deformation severity, while the grains are refined at the subsurface for the low surface deformation during FF loading.

Improvement of the environmental safety of weaving equipment by reducing the wear of contact surfaces

The purpose of the work is improvement of the environmental safety of weaving equipment by reducing the wear of contact surfaces. For the environment, minimizing the wear during the operation of weaving equipment is of great importance. Nevertheless, the physical-chemical interaction of metal surfaces with the environment in its individual sections is uneven due to its polycrystalline structure and heterogeneity. At the same time, the value of their residual stresses (microstresses), the degree of plastic deformation, etc., have a significant effect on the physical and chemical activity of separate surface grains. The article covers the causes of wear of the batten mechanism of a shuttleless loom because of friction. In order to ensure the environmental safety of weaving equipment, methods of increasing the wear resistance of the batten mechanisms of shuttleless looms have been proposed. The article substantiates that an effective method for improving the efficiency of the batten mechanisms of shuttleless looms can be the method of surface plastic deformation of the inner surface of the batten teeth shed. As a result, the uniformity of the physical-chemical interaction of metal surfaces with the environment is ensured, as the resistance to wear and fatigue failure increases.

Justification of the method of surface plastic deformation to strengthen the surface of the shaft under the cuff during repair

The shaft-seal connection is a critical element of any unit, and its reliability is important to ensure the service life of the entire assembly unit. Treatment by surface plastic deformation makes it possible to provide hardening to a depth of up to 2 mm, microhardness increases on average by 150% relative to the initial value, and reaches a value of 6500 MPa. Residual stresses after SPD always have a negative value, the depth of their distribution exceeds the depth of distribution of increased microhardness by 1.5 times, which makes it possible to increase the service life.

ЭВОЛЮЦИЯ КОНСТРУКЦИИ МНОГОКОНТАКТНОГО ВИБРОУДАРНОГО ИНСТРУМЕНТА И ОСНОВНЫЕ ПУТИ ЕГО РАЗВИТИЯ

Methods of surface plastic deformation are considered and a generalized model of a tech-nological system for finishing and strengthen-ing dynamic processing by surface plastic de-formation is proposed. Based on the analysis of the issue and the prospects for the devel-opment of the method of multi-contact vibra-tion shock treatment, an algorithm for the modernization of a multi-contact vibration shock tool is proposed. The scheme of the tool for strengthening hole processing is presented, the main directions of the tool evolution are indicated.

Finite element analysis of stress-strain state of the deformation zone of a UFG TI Grade 4 workpiece subjected to abrasive-free ultrasonic finishing

An effective approach to increasing the fatigue resistance of metal products is to create compressive residual stresses on the surface of the product using surface plastic deformation (SPD) processing. One of the effective SPD methods is the process of abrasive-free ultrasonic finishing (AFUF). Another well-known approach to improving mechanical properties including fatigue resistance is to create an ultrafinegrained (UFG) structural state in the product. This research focuses on the finite-element study of the stress-strain state of a UFG workpiece subjected to SPD by the AFUF method. Commercially pure Grade 4 titanium in the UFG state obtained by the ECAP-Conform method was chosen as a workpiece material. In the course of the study, the stress-strain state of the deformation zone was analyzed after a single indentation with subsequent unloading under the elastic-plastic scenario. The effect of the indenter oscillation amplitude and its geometry on radial residual stresses including their depth of occurrence, average normal stress and strain intensity was analyzed. It was found that as the indenter radius increases, the strain intensity (e) value decreases. The e parameter distribution has a gradient nature with a decrease in values from the surface to the center of the workpiece. An analysis of simulation results shows that radial residual stresses in the deformation zone are predominantly compressive, and, accordingly, they will increase the fatigue resistance of the finished product. It was established that as the indenter oscillation amplitude increases, the values of compressive radial residual stresses also increase. Their maximum values reach 540 MPa at an amplitude of 75 μm with the depth of these stresses up to 0.3 mm. An increase in the indenter radius, i.e. in fact the contact area, leads to an increase in the magnitude of compressive radial residual stresses with an almost linear behavior.

Способы ультразвукового поверхностного пластического деформирования

The existing classification features of ultrasonic surface plastic deformation methods are viewed and their technological capabilities are studied. Methods of ultrasonic surface plastic deformation classification are proposed

ИССЛЕДОВАНИЕ АДГЕЗИОННОЙ СОСТАВЛЯЮЩЕЙ КОЭФФИЦИЕНТА ТРЕНИЯ ИНДЕНТОРА ИНСТРУМЕНТА С ПОВЕРХНОСТЬЮ ДЕТАЛИ ПРИ ОБРАБОТКЕ МЕТОДАМИ ПОВЕРХНОСТНОГО ПЛАСТИЧЕСКОГО ДЕФОРМИРОВАНИЯ

The paper presents the results of studying the parameters of the contact interaction between the tool indenter and the work surface of parts while machining by methods of surface plastic deformation by diamond smoothing and ball burnishing. Changes in the technological factors of diamond smoothing and burnishing under relatively equal machining conditions have different effects on the formation of the topography and parameters of the microprofile. This is due to the contact character of the indenter with the surface. When diamond smoothing, the indenter is rigidly fixed in the tool holder, whereas for ball burnishing the indenter rotates. Accordingly, sliding friction prevails for smoothing, and rolling friction prevails for burnishing. Friction forces in the contact area of the tool indenter with the surface of the part affect the processes. Friction coefficient depends on the deformation and adhesive components. The processes of plastic deformation of metal, the quality of the work surface and other machining parameters in the contact area of the indenter with the work surface are greatly influenced by the strength of the adhesive bond and the molecular component of the friction coefficient. The values of these factors are determined by the combination of materials of the contacting surfaces. This information is often not available in the reference and scientific sources, and theoretical calculations do not allow taking into account real machining factors. The paper presents the methodology and some results of studying the molecular component of the friction coefficient, the specific strength of the adhesive bond and the pressure coefficient in the contact area of the indenter with the surface during diamond smoothing and ball burnishing. The presented results give the scientific novelty of the paper.

Hardening technology designing of parts by dynamic surface plastic deformation methods

Calculation dependences are proposed, which allow substantiating the quality parameters of the surface layer of parts hardened by dynamic methods of surface plastic deformation from the standpoint of the energy approach. An algorithm for designing a hardening treatment technology has been developed based on the energy assessment of the quality parameters of the surface layer and the fatigue life of parts operating under cyclic loads.

Effect of combined machining on structure and properties of electrospark coatings on low-carbon Steel by self-fluxing special electrode

The methods of surface-plastic deformation are considered. The process of production and processing of steel strip from low-carbon steel is considered. The results of a study of the effect of combined processing on the structure and physical and mechanical properties of electrophysical coatings deposited on low-carbon steel after burnishing with a specially designed tool and devices are presented. The optimal burnishing mode for mineral ceramics VOK-60 is determined. The number of pores in the coating was determined by the eddy current method.

Электроискровое упрочнение дереворежущего инструмента

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

Modeling of the Contact Interaction of the Tool Indenter with the Part Surface when Processing by Surface Plastic Deformation Methods

There are results of studying the parameters of the indenter contact interaction with the surface when processing cylindrical parts made of 45 steel of different hardness by surface plastic deformation (SPD) methods with single-indenter elastic tools (diamond burnishing, ball burnishing). There were considered such characteristics as the resistance force when the indenter starts and in the steady state of SDP, the range of force fluctuations during processing, friction factor when the indenter starts and in the steady state, as well as some derivative coefficients. Adequate physical-statistical models for the quantitative estimation of the contact interaction parameters from SPD processing factors are obtained.

Numerical Study of Stress-Strain State of Workpiece in Contact Problem of Surface Mandrel Drilling

In recent years, the economic factor has played an increasingly important role in the selection of technologies for manufacturing machine parts with specified values of normalized parameters of geometric accuracy and quality of working surfaces. As applied to surface plastic deformation processes, this is noticeably manifested in the search for effective friction control methods in the “tool – workpiece” pair, which ultimately determines the distribution pattern and the magnitude of stresses and strains in the workpiece and the tool. It is not possible to obtain a rigorous analytical solution to the problem of establishing a connection between surface conditions, friction, and the stress-strain state of the contacted bodies. In this regard, the construction of mathematical models comes to the fore, the solution of which is possible by numerical methods. The paper presents the results of a numerical study (computational experiment) of a finite-element model of workpiece deformation under various conditions of contact interaction and friction by one of the methods of surface plastic deformation – surface mandrel drilling. The friction coefficient has been chosen as the criterion for assessing the conditions of contact interaction and friction. It is shown that a change in the friction coefficient in the process of surface mandrel has no noticeable effect on the formation of a stress field in the deformable workpiece both in the axial, and in the radial and circumferential directions. At the same time, with an increase in the value of the friction coefficient in the “tool – workpiece” pair and with the associated increase in the force of mechanical resistance to deformation of the workpiece, their growth is observed. A computational experiment has confirmed the presence of non-contact deformations of the workpiece and tool during surface mandrel drilling, as well as as a decrease in the value of residual deformations in the workpiece with a decrease in the coefficient of friction. Balance assessment of contact surface displacements in the workpiece (the inner surface of the hole to be machined) and the tool (mandrel) has shown that the deformations of the tool in the elastic region can lead to a significant decrease in the real tightness of surface mandrel drilling.

Technological stability of processing the machine part surface by methods of surface plastic deformation with elastic action tools

The article presents the results of physical modelling of the processes of diamond burnishing of machine part surfaces with a complex differentiable profile and the concept of technological stability of treatment processes by methods of surface plastic deformation of surfaces with elastic action tools. The criteria for technological stability of the treatment process under the specified conditions are determined.

Investigation of tool wear resistance when smoothing parts

The article discusses the method of surface plastic deformation of steel parts by smoothing. The positive influence of this method on the wear resistance of the tool has been established under conditions of intense wear and with abundant lubrication

Technological features of crankshaft hardening by vibration shock method

Introduction. The technological features of the processing crankshafts by the vibration shock method of surface plastic deformation (SPD), which is widely used in the technology of manufacturing machine parts, are considered. Theresearch objective is to justify the efficiency of the influence of vibration shock hardening treatment on improving the quality and performance of crankshafts (CS). Materials and Methods. The methodological studies included the validation of the vibration shock processing flowchart and the development of an analytic model for assessing the effect of processing on the change in the macrogeometry (warpage) of the CS. Results. Flowcharts have been developed for volumetric vibration shock finishing and hardening treatment of CS using a vibratory machine with a U-shaped work chamber. Its overall dimensions measure alike or exceed the overall dimensions of the CS being processed, and ensure the location of the shaft in such a way that its main axis, coinciding with the axis of the main bearing journals, is in the zone of the conditional axis of working mass rotation. The surface quality parameters were investigated during their processing on the UVG 4X10 vibratory unit according to the proven techniques using the dedicated tooling. It has been established that the vibration shock hardening treatment (ViHT) enables, due to plastic deformation of microroughness, to obtain a qualitatively new surface microrelief and to reduce its initial roughness, to drastically increase the surface microhardness of the CS main and rod journals; at that, it changes the stressed state of their surface layer. A calculated dependence is proposed to assess the total warpage of the CS strengthened under the ViHT, and its adequacy is confirmed. It is shown that the warpage of the shaft after the ViHT is due to the different tension of the rod and main journals of the CS at the level of Кн ≈ 0.6. Discussion and Conclusions. Vibration shock treatment of CS provides an improvement in the geometric and physicomechanical parameters of surfaces of the rod and main journals. As a result of processing all surfaces of the shaft, warpage does not exceed the permissible values established by the technical requirements. So, we can conclude on the efficiency of the considered method of hardening CS with the aim of increasing their operational properties.

Quality improvement of calibrated steel by surface deformation. Part 1. Determination of the stressed state of cylinderical parts during orbital surface deformation

Cold drawn calibrated steel is an effective blank for the manufacture of low-rigid cylindrical parts such as shafts and axles. High accuracy of the diametric size along the length of the workpiece, low surface roughness, increased hardness and strength of the surface layer compared to hot rolled products allow us to produce a variety of parts with high metal utilization and high machining performance. The main disadvantage of calibrated metal is the residual stresses that occur during pressure treatment. To reduce or change the nature of the distribution over the cross section, it is proposed to use small plastic deformations in the surface layer of the hire. Known in practice methods of surface plastic deformation (PPD) usually lead to the curvature of non-rigid workpieces. To intensify the stress-strain state in the deformation zone, we propose a method of orbital surface deformation. Based on the finite element modeling, influence of the main parameters of orbital surface deformation on stress state in the deformation zone and residual stresses in the finished products is considered. Compared with the traditional PPD process, the stress intensity during orbital surface deformation will increase by 10 – 15 %. The residual compressive stresses that form in the surface layers reach 70 – 85 % of the material tensile strength. In the second part of the article, it is supposed to provide information on a more effective method of surface deformation and on the change in initial residual stresses that are formed during the calibration of cylindrical rods.