Numerical Analysis of the Die Forging of Porous Blanks in a Die with the Implementation of Active Friction Forces

2021 ◽  
Vol 62 (1) ◽  
pp. 119-124
Author(s):  
G. A. Bagliuk ◽  
S. F. Kyryliuk
Author(s):  
G. A. Bagliuk ◽  
S. F. Kyryliuk

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.


Technologies ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 70 ◽  
Author(s):  
Grigoriev ◽  
Dmitriev ◽  
Korobova ◽  
Fedorov

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.


Author(s):  
Viktor Matviychuk ◽  
Mykola Kolisnyk

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.


Author(s):  
M.I. BORZENKOV ◽  
I.S. VDOVIN ◽  
Yu.S. RADCHENKO ◽  
N.V. TATARCHENKO

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.


Author(s):  
B.S. Moroz ◽  
M.G. Dudnik

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.


2007 ◽  
Vol 26-28 ◽  
pp. 69-72 ◽  
Author(s):  
Young Seon Lee ◽  
Y.C. Kwon ◽  
Yong Nam Kwon ◽  
Jung Hwan Lee ◽  
S.W. Lee ◽  
...  

Internal voids have to be eliminated for defect-free in some open die forging. The FEM analysis is performed to investigate the overlap defect of cast ingots during cogging stage. The measured flow stress data were used to simulate the cogging process of cast ingot using the practical material properties. Also the numerical analysis of void closure is performed by using the DEFORMTM-3D. The calculated results of void closure behavior are compared with the measured results before and after upsetting, which are scanned by the X-ray scanner. From this result, the criteria for deformation amounts effect on the void closure were estimated into effective strain of 0.6 by the comparison of practical experiment and numerical analysis.


2020 ◽  
Vol 6 (3) ◽  
pp. 28-32
Author(s):  
Rano Khurramova ◽  
◽  
Bahrom Yuldashev ◽  
Lutfullo Kuldashev ◽  
◽  
...  

Taking into account the friction forces and inertia of the gas, formulas for the hydraulic calculation of the inclined section of the main gas pipeline (MG) are obtained and a numerical analysis of the influence of force factors on the nature of the change in gaspressure along the length of the gas pipeline is carried out


Author(s):  
A.A. Pasynkov ◽  
S.N. Larin ◽  
A.N. Isaeva

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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