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

2020 ◽  
Vol 63 (10) ◽  
pp. 802-807
Author(s):  
S. A. Zaides ◽  
. Pham Van Anh
Keyword(s):  
Surface Layer ◽  
Residual Stresses ◽  
Deformation Zone ◽  
Surface Deformation ◽  
Surface Plastic Deformation ◽  
Surface Plastic ◽  
Machining Performance ◽  
Cylindrical Parts ◽  
Practice Methods ◽  
Hot Rolled

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.

scholarly journals Influence of reinforcing plastic surface deformation on surface performance of machine parts

2019 ◽  
pp. 7-14
Author(s):  
Z. М. Оdosii ◽  
V. Ya. Shymanskyi ◽  
B. V. Pindra
Keyword(s):  
Plastic Deformation ◽  
Surface Layer ◽  
Residual Stresses ◽  
Surface Deformation ◽  
Fatigue Cracks ◽  
Surface Plastic Deformation ◽  
Original Structure ◽  
Physical Parameters ◽  
Surface Plastic ◽  
Machine Parts

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.

Determining the Quality of the Surface Layer of Low-Stiff Cylindrical Products after Straightening with Transverse Burnishing with Smooth Plates

2019 ◽  
pp. 5-13
Author(s):  
S.A. Zaides ◽  
Quang Le Hong
Keyword(s):  
Surface Layer ◽  
Residual Stresses ◽  
Sharp Decrease ◽  
Surface Plastic Deformation ◽  
Surface Plastic ◽  
Surface Layers ◽  
Compressive Stresses ◽  
Cylindrical Parts ◽  
Compressive Residual Stresses

To restore the shape of low-stiff cylindrical parts such as shafts and axles, straightening by transverse bending with the subsequent processing of workpieces by the method of surface plastic deformation based on the transverse burnishing with smooth plates is proposed. The experimental and calculated results are presented to determine the effect of absolute compression on the main characteristics of the quality of the surface layer of parts such as surface roughness and residual stresses. The analysis of experimental data for the evaluation of the parts after straightening by transverse burnishing showed the following positive changes: a sharp decrease in the initial roughness, the formation of equilibrium residual compressive stresses in the surface layers and ensuring stabilization of the accuracy of the processed part in size and shape. Depending on the magnitude of the absolute reduction, the surface quality increases by 2–3 classes, and rather large compressive residual stresses are formed (up to 375 MPa). The results of the work justify recommending the proposed method of straightening by transverse burnishing with smooth plates for implementation into the technology of machine part restoration.

scholarly journals Relaxation patterns of technological residual voltage in the surface layer of high-strength steel when cyclically loaded

2021 ◽  
Vol 244 ◽  
pp. 04001
Author(s):  
Georgi Kravchenko ◽  
Konstantin Kravchenko ◽  
Andrey Smolyaninov ◽  
Irina Kudryavtseva
Keyword(s):  
Surface Layer ◽  
Residual Stresses ◽  
Construction Materials ◽  
High Strength ◽  
Surface Plastic Deformation ◽  
Variable Pressure ◽  
Surface Plastic ◽  
Initial Value ◽  
Residual Voltage ◽  
Compressive Stresses

Experimentally investigated patterns of changes in technological residual stresses under the influence of variable pressure in the surface layer became 30XNS2A. A mathematical model of relaxation of residual compressive stresses created by surface plastic deformation techniques with symmetrical cyclical bending of samples has been proposed. An empirical expression is proposed for assessing the final value of residual stresses as a result of cyclic loading, depending on the stress amplitude of a symmetric cycle. An expression is given for estimating the coefficient of relaxation rate of residual compressive stresses from their initial value, amplitude of alternating stresses and material properties. The constants of these expressions are determined for various construction materials. The theoretical dependences describe well the obtained experimental data. To predict the level of residual stress realization under operational loading, a formula was obtained to calculate their change as a result of the action of a step loading block with different amplitudes and duration of their action at each of the stages.

Influence of the deforming tool kinematics on the stress state of the surface layer during hardening of cylindrical parts

2021 ◽  
pp. 28-32
Author(s):  
Keyword(s):  
Plastic Deformation ◽  
Surface Layer ◽  
Stress State ◽  
Surface Plastic Deformation ◽  
Surface Plastic ◽  
The Finite Element Method ◽  
Kinematic Scheme ◽  
Local Surface ◽  
Hardening Process ◽  
Cylindrical Parts

The influence of kinematic schemes of processing by local surface plastic deformation on the intensification of the stressed state of cylindrical surfaces of parts is considered. On the basis of the finite element method by computer simulation, a mathematical model of the hardening process was obtained to determine the stress state in the surface layer for different hardening schemes. Keywords: kinematic scheme of processing, deforming tool, orbital burnishing, intensification of the stress state, residual stresses, depth of plastic deformation. [email protected], [email protected]

TECHNOLOGY OF COMBINED ELECTROMECHANOULTRASONIC TREATMENT OF SURFACE LAYERS OF MACHINE PARTS

2020 ◽  
Vol 2 ◽  
pp. 26-33
Author(s):  
V.R. EDIGAROV
Keyword(s):  
Plastic Deformation ◽  
Surface Layer ◽  
Residual Stresses ◽  
Ultrasonic Treatment ◽  
Mechanical Treatment ◽  
Surface Plastic Deformation ◽  
Surface Plastic ◽  
Surface Layers ◽  
Machine Parts ◽  
Acoustic Treatment

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.

scholarly journals Dependence of the limit endurance of specimens with notches from the depth of hardened surface layer

2018 ◽  
Vol 84 (8) ◽  
pp. 44-49
Author(s):  
V. S. Vakulyuk ◽  
V. K. Shadrin ◽  
N. A. Surgutanov
Keyword(s):  
Surface Layer ◽  
Residual Stresses ◽  
Endurance Limit ◽  
Surface Plastic Deformation ◽  
Fatigue Tests ◽  
Surface Plastic ◽  
Outer Diameter ◽  
Notched Specimens ◽  
Compressive Residual Stresses ◽  
Dangerous Section

It is shown that, growth of the layer with compressive residual stresses at advanced surface plastic deformation of smooth samples leads to an increase in the endurance limit of the notched specimens due to an increase in the compressive residual stresses in their dangerous section. The study was conducted on the specimens with outer diameterDequal to 10 and 25 mm and on a 25 mm specimen with inner diameterd= 15 mm which were subjected to air shot blasting and roll-in. Residual stresses in smooth specimens were determined by the mechanical method. Circular incisions (R= 0.3 and 0.5 mm) were applied on hardened smooth samples with a shaped cutter. Residual stresses in notched specimens were determined by a numerical method calculating the redistribution of the residual stresses upon the incision. As the diameter of the samples increases with the same strengthening surface treatment,the depth of the layer with the compressive residual stresses increases due to an increase in the rigidity of the samples. The effect of surface hardening on the endurance limit of notched specimens was evaluated according to the criterion of the average integral residual stresses, which takes into account both the magnitude and completeness of the residual stresses. This criterion was calculated from the depth of the non-propagating fatigue crack that occurs in the surface layer in the dangerous section of the specimen during the fatigue test at the limit endurance. Fatigue tests are carried out in symmetrical cycle, the test base being 3 × 106cycles of loading. Estimation of the increment of the limit endurance of surface-hardened cylindrical specimens with semicircular notches gave the results acceptable for practice. The use of the proposed method can significantly reduce long-term and expensive fatigue tests.

scholarly journals The Metal Surface Layer Mechanical Condition Transformation in Machining Processes

2019 ◽  
Vol 297 ◽  
pp. 05001
Author(s):  
Valeriy Blumenstein ◽  
Maxim Makhalov
Keyword(s):  
Surface Layer ◽  
Residual Stresses ◽  
Metal Surface ◽  
Product Life Cycle ◽  
Surface Plastic Deformation ◽  
Surface Plastic ◽  
Axial Component ◽  
Machining Processes ◽  
Mechanical Condition ◽  
Metal Surface Layer

The metal surface layer mechanical condition transformation at the product life cycle stages key provisions are presented. The described approach feature is the hardened body effect consideration: the metal mechanical properties changing during it displacement through the deformation zone space. On the basis of the developed for surface plastic deformation process hardened elastic-plastic body model, the cumulative shear strain level, plasticity reserve exhaustion level and residual stress tensor components calculations are performed. It is established that the greatest residual compressive stresses are characteristic for the axial component, and the extremum can be located both on the workpiece surface and at some distance from it. The metal hardening influence on the residual stresses distribution is revealed. On the axial (largest) component example shown that the difference between the maximum values is almost 30%. The obtained result corresponds to the idea that the hardened metal having an increased yield strength allows a larger residual stresses presence.

scholarly journals Quality improvement of calibrated steelby surface deformation. Part 2. Effect of enveloping surface deformation on residual stresses in cylindrical bars

2021 ◽  
Vol 64 (5) ◽  
pp. 330-336
Author(s):  
S. A. Zaides ◽  
Van Anh Pham ◽  
L. G. Klimova
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
Residual Stresses ◽  
Surface Deformation ◽  
High Surface ◽  
Surface Plastic Deformation ◽  
Surface Plastic ◽  
Surface Layers ◽  
Tensile Stresses ◽  
Enveloping Surface

Cold-drawn metal has a number of undeniable advantages over the hot-rolled one. Increased hardness, high surface quality, stability of the diametrical dimension along the length of the workpiece are the basis for choosing calibrated metal as effective workpieces for the manufacture of long parts such as shafts, axles, and rods. In some cases, such workpieces require a small amount of machining, for example, threading or making necks at the ends of a bar. The wider use of the calibrated metal is hindered by residual stresses that are formed during its manufacture. In the first part of this article, it was proposed to use small plastic deformations to control residual stresses. By the example of a new process of surface plastic deformation, which is called orbital burnishing, the working and residual stresses in cylindrical workpieces are determined. In the second part of the article, the process of enveloping surface plastic deformation is considered, which, at high productivity, makes it possible to reduce the residual tensile stresses in the calibrated metal or form the surface layers of the workpiece compressive stress. A technique for the experimental determination of residual stresses in the volume of a body is based on layer-by-layer removal of the inner and outer layers of cylindrical samples. Influence of the main parameters of the enveloping deformation process on the components of the residual stress tensor is established. A range of relative compressions (0.1 – 1.0 %) is revealed, at which residual compressive stresses are formed in the surface layers of the workpiece. It was found that at a relative compression of 0.5 %, the maximum residual compression stresses are created. Enveloping surface deformation has a positive effect on the residual stress state and on colddrawn metal – the residual tensile stresses can be reduced, removed or converted into compressive ones.

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