scholarly journals FORMATION OF QUALITATIVE INDICATORS OF PRODUCTS BY ROLLING STAMPING PROCESSES

2021 ◽  
pp. 75-83
Author(s):  
Viktor Matviychuk ◽  
Mykola Kolisnyk
Keyword(s):  
Wall Thickness ◽  
Relative Difference ◽  
Workpiece Material ◽  
Friction Forces ◽  
Utilization Factor ◽  
Service Characteristics ◽  
Metal Stamping ◽  
Active Friction ◽  
Deformation Kinematics ◽  
Active Friction Forces

The influence of rolling stamping on the service characteristics of products is investigated in the work. Based on the analysis of deformation kinematics, stress-strain state, microstructure and evaluation of deformability of workpiece material, ways to increase geometric accuracy, vacuum tightness, electrolytic stability and mechanical characteristics of product material, as well as ways to improve the material of workpieces for their subsequent processing. The influence of active friction forces on the nature of the material flow during SHO was established, which contributed to the development of new processes that allow to bring the shape and dimensions of the workpiece as close as possible to the finished part. Thus accuracy of the sizes of details corresponds to 7-11th qualities of accuracy, and roughness of the processed surfaces makes Ra = 2,5… 0,63 microns. The process of reshaping the square billets into round ones by the method of SHO is effective, which increases the utilization factor of the metal and reduces the anisotropy of its mechanical properties. The characteristic of flat anisotropy λr, adopted in sheet metal stamping as a characteristic of the ability of the material to form scallops, decreases as a result of reshaping by 70-80%. The relative difference in yield strength in the plane of the sheet decreases from 0.10-0.15 to 0.03-0.05. The ultimate tensile strain increases by 8-10%, and the uniform uniform strain - by 5-8%. This improvement in the characteristics of the material reshaped by rolling blanks leads to the fact that when drawing cylindrical products, the value of scallops decreases by 2-2.5 times, and the value of the maximum degree of drawing increases by 10-15%. This reduces the relative difference in wall thickness along the perimeter of the elongated workpiece, and the change in wall thickness along its height becomes linear. Thus, the use of SHO processes significantly improves the quality characteristics of products.

scholarly journals A Cold-Pressing Method Combining Axial and Shear Flow of Powder Compaction to Produce High-Density Iron Parts

Technologies ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 70 ◽  
Author(s):  
Grigoriev ◽  
Dmitriev ◽  
Korobova ◽  
Fedorov
Keyword(s):  
Material Flow ◽  
Axial Loading ◽  
Powder Compaction ◽  
Friction Forces ◽  
Pressing Method ◽  
Cold Pressing ◽  
Traditional Design ◽  
Active Friction ◽  
Set Up ◽  
Active Friction Forces

Highly performance methods for cold pressing (cold die forging) of preforms from iron powder with subsequent heat treatment and producing ready parts made of powder are described in the paper. These methods allow fabricating parts with smooth surfaces and improved mechanical characteristics—porosity, tensile strength. Application of the traditional design set-up with a single-axial loading is restricted to high stresses in the dies to deform the preforms that lead to cracks formation. New powder compaction schemes by applying active friction forces (shear-enhanced compaction) make it possible to unload dies and produce high-quality parts by cold pressing. The scheme allows moving the die in the direction of the material flow with a velocity that exceeds the material flow velocity.

PIPE BENDING WITH APPLICATION OF ACTIVE FRICTION FORCES

2020 ◽  
Vol 6 ◽  
pp. 58-61
Author(s):  
M.I. BORZENKOV ◽  
I.S. VDOVIN ◽  
Yu.S. RADCHENKO ◽  
N.V. TATARCHENKO
Keyword(s):  
Engineering Analysis ◽  
Active Deformation ◽  
Friction Forces ◽  
Active Friction ◽  
Active Friction Forces ◽  
Deformation Area ◽  
Pipe Bending

An engineering analysis of pipe bending along a circular copier with a deviation of flat material sections from the normal (by Love) position is performed, the dimensions of the active deformation area and the reactions of tools that generate friction forces are determined.

Numerical analysis of porous blank die forging in the die with the implementation of active friction forces

2020 ◽  
pp. 17-24
Author(s):  
G. A. Bagliuk ◽  
S. F. Kyryliuk
Keyword(s):  
Material System ◽  
Porous Powder ◽  
Compression Force ◽  
Friction Forces ◽  
High Deformation ◽  
Deformation Intensity ◽  
Die Forging ◽  
Active Friction ◽  
Deformation Force ◽  
Active Friction Forces

The paper provides the results of simulating the hot die forging of porous powder preforms with active friction forces applied along the lateral surface of the deformable blank by means of internal cohesion in the die-material system. The study covers the evolution of relative density distribution over the blank cross section at different stages of deformation, stress-strain state and total strain force while varying the loading boundary conditions by changing the initial compression force applied to elastic elements that prevent the die from displacement. It is shown that active friction forces acting on the periphery of the forging adjacent to the die inner side result in areas with a significantly higher deformation intensity compared to deformations in the center of the blank volume. At the same time, the volume of the high deformation intensity area and maximum values of deformation increase with a decrease in the spring initial compression force and, accordingly, with an increase in the die displacement value during deformation. Automatic die displacement due to internal cohesion in the die-deformable material system leads to a decrease in the total deformation force, and with a decrease in the die displacement value during deformation, the deformation force increases.

Effect of active action friction forces on technological parameters of backward extrusion

2021 ◽  
pp. 25-33
Author(s):  
B.S. Moroz ◽  
M.G. Dudnik
Keyword(s):  
Extrusion Process ◽  
Technological Parameters ◽  
Deformation Degree ◽  
Friction Forces ◽  
Backward Extrusion ◽  
Deformation Force ◽  
Active Friction Forces ◽  
The Impact ◽  
Experimental Researches ◽  
Experimental And Theoretical Studies

The parameters of deformation degree at theoretical and experimental researches of cold backward extrusion processes of hollow glasses-type products are considered. The dependences of their relationship with the relative degree of deformation and the scale of their conformity are suggested. The published results of experimental and theoretical studies on the impact of technological parameters of the backward extrusion process of hollow products in the conditions of active friction forces to reduce the deformation force and stress-strain state of the billet are analyzed. Insuffi ciently studied features of the process and the possibility for expanding of the application fi eld of the backward extrusion method with the active action of friction forces are noted. The method for calculating of the deformation rate required to determine the current stress in the implementation of the hot backward extrusion process.

Research of the Influence of the Physical and Mechanical Properties of the Workpiece Material on the Temperature Field of the Turning Process

2021 ◽  
Vol 1037 ◽  
pp. 300-308
Author(s):  
Alexander N. Unyanin ◽  
Pavel R. Finageev
Keyword(s):  
Cutting Force ◽  
Yield Stress ◽  
Physical And Mechanical Properties ◽  
Tangential Component ◽  
Machining Process ◽  
Regression Equations ◽  
Workpiece Material ◽  
Friction Forces ◽  
The Face ◽  
Contact Surfaces

To predict the parameters of the quality of the processed parts and the period of durability of the cutting tool, mathematical models are needed that will allow us to calculate not only the mathematical expectation of the parameters of the machining process, but also the dispersion of these parameters. The working capacity of the tool and the quality parameters of the parts depend significantly on the temperature on the contact surfaces of the tool, as well as on the surface of the workpiece. Mathematical dependences for calculating the components of the total heat generation capacity during turning are given. It is assumed that the yield stress, which determines the cutting and friction forces on the contact surfaces of the cutter, workpiece and chip, depends on the temperature in the area of plastic deformation. The heat transfer at the boundaries of objects in contact with the process fluid or air is given in the form of the Newton-Richman law. The equations of thermal conductivity of contacting objects were solved together with the general boundary conditions in the contact zone, using the finite element method. The results of numerical simulation of the main component of the cutting force and temperatures in the contact zones of the face of the cutter with the chips and the fiank surface with the workpiece, depending on the yield strength of the workpiece material, are presented. The values of fluctuations in the cutting force and contact temperatures depending on the spread of the yield stress of the workpiece material during turning of workpieces made of 45 and 12X18H10T steels are determined. Based on the results of numerical modeling, regression equations are obtained for calculating the tangential component of the cutting force, the temperatures on the face and flank surfaces of the cutter, and the temperature on the surface of the workpiece.

Dimensional Changes in Tube Swaging

1966 ◽  
Vol 88 (2) ◽  
pp. 147-150 ◽  
Author(s):  
Serope Kalpakjian
Keyword(s):  
Wall Thickness ◽  
Appreciable Effect ◽  
Process Variables ◽  
Workpiece Material ◽  
Thickness Increase ◽  
Dimensional Changes ◽  
Independent Variables ◽  
Rotary Swaging ◽  
Diameter Reduction ◽  
Wall Thickness Increase

The purpose of this study was to investigate changes in the wall thickness of tubes sunk by the rotary swaging process. The independent variables were: Workpiece material, original wall thickness of tube, die angle, die overgrind, and diameter reduction. The results indicated that of these five variables only the diameter reduction was a factor in wall-thickness increase. Material and other process variables did not appear to have appreciable effect within the range studied.

Theoretical substantiation of reverse isothermal extrusion scheme of pipe billet with active friction and drawing of its edge part

2020 ◽  
pp. 540-543
Author(s):  
A.A. Pasynkov ◽  
S.N. Larin ◽  
A.N. Isaeva
Keyword(s):  
Stress State ◽  
Extrusion Process ◽  
Friction Forces ◽  
Theoretical Substantiation ◽  
Tube Billet ◽  
Active Friction ◽  
Edge Part ◽  
Simultaneous Use ◽  
Isothermal Extrusion

Method consisting in the implementation of the reverse extrusion process of tube billet in isothermal сondition of stamping with active friction is considered. Feature of the method is the simultaneous use of friction forces and pushing of the formed thickened edge part of the workpiece and its further straightening. The force conditions and stress state in the product are estimated. Comparison of this method with the classical extrusion scheme is given.

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