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.

scholarly journals The Method of Reconstruction of Residual Stresses in a Prismatic Specimen with a Notch of a Semicircular Profile after Advanced Surface Plastic Deformation

2020 ◽  
Vol 20 (4) ◽  
pp. 478-492
Author(s):  
Vladimir P. Radchenko ◽  
◽  
Dmitry M. Shishkin ◽  
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
Residual Stresses ◽  
Numerical Method ◽  
Stress Tensor ◽  
Stress Concentrator ◽  
Hardened Layer ◽  
Surface Plastic Deformation ◽  
Surface Plastic ◽  
Model Calculations

The stress-strain state in a surface-hardened bar (beam) with a stress concentrator of the semicircular notch type is investigated. A numerical method for calculating the residual stresses in the notch region after an advanced surface plastic deformation is proposed. The problem is reduced to the boundary-value problem of fictitious thermoelasticity, where the initial (plastic) deformations of the model are simulated by temperature deformations in an inhomogeneous temperature field. The solution is constructed using the finite element method. For model calculations, experimental data on the distribution of residual stresses in a smooth beam made of EP742 alloy after ultrasonic mechanical hardening were used. The effect of the notch radius and beam thickness on the nature and magnitude of the distribution of the residual stress tensor components in the region of the stress concentrator is studied. For the normal longitudinal component of the residual stress tensor, which plays an important role in the theory of high-cycle fatigue, it was found that if the radius of a semicircular notch is less than the thickness of the hardened layer (area of material compression), an increase (in modulus) of this component of residual stresses occurs in the smallest section of the part (in the volume immediately adjacent to the bottom of the concentrator). If the depth of the notch is greater than the thickness of the hardened layer, then a decrease (in magnitude) of this value is observed in comparison with a smooth hardened sample. It is shown that in a reinforced notched beam, the deflection value due to induced self-balanced residual stresses is less than in a smooth beam. Experimental verification of the developed numerical method is done for a surface-hardened smooth beam made of EP742 alloy.

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 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.

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 Development and modeling of a device for strengthening the channels of gun barrels by the method of vibration-centrifugal processing

2019 ◽  
Vol 21 (91) ◽  
pp. 118-123
Author(s):  
V. I. Topchii ◽  
I. S. Aftanasiv ◽  
I. G. Svidrak
Keyword(s):  
Plastic Deformation ◽  
Surface Plastic Deformation ◽  
Strength Characteristics ◽  
Surface Plastic ◽  
Surface Layers ◽  
Chemical Action ◽  
Gun Barrel ◽  
Working Surface ◽  
And Performance ◽  
Materials Used

The paper proposes a fundamentally new method of vibration-centrifugal hardening of internal cylindrical surfaces of long-length steel parts, in particular artillery guns, belonging to a group of methods of surface plastic deformation, and is characterized by providing a significant level of energy for deformation of the material being processed. Artillery cannons, along with a system for targeting shooting guns, are perhaps the most responsible component, which not only provides range and accuracy of the aiming shot, but also regulates the durability of the gun in general. During each of the gun shots, the surface layers of the metal of the channel of its trunk are exposed to the destructive effects of high (up to 10000 °C) temperatures, the chemical action of powder gases, excessive pressures and mechanical wear on the movement of the shell. This leads to the destruction of the structure, strength and density of the metal surface layers, its burning and wear, which in the rest, leads to violations of the geometry of the working surface of the trunk channel. Violation of the geometry of the working surface of the channel of the gun barrel negatively affects the range, and most importantly, the precision of gunfire and other precision related tactical and technical characteristics of gun armament. Excessively worn internal working surface of the canal of the trunk of repair and restoration is practically not subject. This determines the availability of such characteristics for cannon weaponry as the permissible number of gunfire shots, which to a certain extent limits the duration of the effective use of guns. A rather common practice in mechanical engineering is that when the strength characteristics and capabilities of the materials used are practically exhausted, designers and developers draw their views on the technological capabilities to improve the operational properties of parts and units. Not the last position in their list is the reinforcing operations of the surface layers of the material of the details by various methods of surface plastic deformation, widely known in the literary primary sources under the acronym “PPE methods”. The common advantage of the best of a fairly wide variety of varieties (rolling, rolling, smoothing, blasting and vibrating processing, etc.) is that, without substituting the part for energy-intensive high-temperature heating, the strength characteristics and performance properties of the most loaded surface layers of the material of parts are improved. Accordingly, the use in manufacturing processes of the details of PPD methods helps to increase their reliability and longevity. The developed design of the reinforcement on the basis of the proposed method of vibration-centrifugal hardening treatment is used to strengthen the internal cylindrical channels of the trunk of large-caliber artillery cannons. The reinforcement is simple in structure, energy-saving, does not provide for the maintenance of highly skilled service personnel. The solid-state model of the device for the vibration-centrifugal hardening of the internal cylindrical surfaces of steel parts has been created

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.

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