Effect of deformation hardening intensity, contact friction and back tension on indicators of wire drawing process

2021 ◽  
pp. 11-22
Author(s):  
G.N. Gur’yanov ◽  
N.G. Gur’yanov
Keyword(s):  
Safety Factor ◽  
Wire Drawing ◽  
Contact Friction ◽  
Tension Stress ◽  
Drawing Process ◽  
Drawing Stress ◽  
Deformation Hardening ◽  
Drawing Angle ◽  
First Time ◽  
Hardening Coefficient

Dependences on the hardening factor for the drawing stress, the safety factor of I.L. Perlin and the stress state indicator V.L. Kolmogorov at different values of the drawing angle, coefficient of friction and stress of back tension are presented. For the first time, the nature of the dependences for the limiting and permissible values of delta-criterion is shown for the shape of the deformation zone of round solid profile on the coefficients of friction, hardening and safety factor and the back tension stresses. The limiting and permissible values of the delta-criterion increase from increase in the coefficients of friction and safety factor, the back tension stress and decrease from increase in the hardening coefficient. It is shown that for small values of the criterion ∆ < 1.5, the drawing stress can be higher than the yield point at the die output. As result, the wire material may be destroyed and the drawing process cannot be realized. Assessment of the change degree in the limiting and permissible values of the elongation coefficient and delta-criterion is carried out with increase in the friction coefficient from 0.05 to 0.15, the back tension from 0 to 85 MPa, the safety factor from 1.0 to 1.4, the hardening coefficient from 0 to k.

Graphical method for determining of limit and permissible values of drawing and friction coefficients, stress, drawing angle and delta-criterion for shape of plastic deformation zone

2021 ◽  
pp. 55-66
Author(s):  
G.N. Gur’yanov
Keyword(s):  
Safety Factor ◽  
Coefficient Of Friction ◽  
Plastic Deformation Zone ◽  
Tension Stress ◽  
Abscissa Axis ◽  
Limit Values ◽  
Drawing Stress ◽  
Optimal Value ◽  
The Coefficient Of Friction ◽  
Drawing Angle

The maximum and permissible values of the coefficients of drawing and friction, the Delta criterion of the shape of the deformation center, the index of the deformed state, the angle and drawing stress are determined graphically for different models of hardening and values of the anti-tension stress. For the determination, cartesian graphs were used, on the ordinate axis of which the desired indicators are located, and on the abscissa axis the values of the I.L. Per lin safety factor obtained by varying the extraction coefficient. The permissible values of the drawing coefficient and drawing stress decrease with the growth of the safety factor of I.L. Perlin. The dependence of the limit and permissible values of the Delta criterion for the optimal value of the drawing angle on the deformation parameters and the harden ing model is shown. The maximum and permissible values of the coefficient of friction are higher at the optimal value of the drawing angle. For the first time, the possibility of increasing the limit value of the coefficient of friction from the action of anti-gravity is established. The limit and permissible values of the coefficient of friction decrease with the increase in the value of the coefficient of drawing and increase with the increase in the coefficient of hardening k. Curves for the dependences of the safety factor, the stress state indicator and the absolute safety margin Zap on the value of the drawing angle fix small and large values of the limit drawing angle on the abscissa axis. Small limit values of the drawing angle do not differ significantly in value for different values of the drawing and hardening coefficients, in contrast to large limit values of the angle. The action of counter-gravity increases the small limit angles and decreases the large limit angles. Determination of the limit and permissible values of the coefficients of drawing and friction, the Delta criterion, stress and drawing angle contributes to the rational choice of modes of deformation of the wire (bar).

Determination of limiting and legitimate values of drawing coeffi cient and delta-criterion for deformation zone shape during wire drawing

2021 ◽  
pp. 168-178
Author(s):  
G.N. Gur'yanov
Keyword(s):  
Friction Coefficient ◽  
Safety Factor ◽  
Deformation Zone ◽  
Wire Drawing ◽  
Deformation Parameters ◽  
Deformed State ◽  
Rod Breakage ◽  
Drawing Angle ◽  
Limiting Values

The limiting and legitimate values of the drawing coefficient and delta-criterion Δ for the deformation zone shape depending on the friction coefficient for different models of hardening and the values of the drawing angle and the back-pull stress are determined by numerically solving the corresponding equations. The limiting and legitimate values of the drawing coefficient decrease with increase in the friction coefficient, while the analogous values of the criterion increase. Increase in the safety factor causes decrease in the allowable drawing and increase in the delta-criterion. The limiting and legitimate values of the drawing coefficient decrease from the application of back tension in the absence of strain hardening. The nature of the effect of back tension on the limiting and legitimate values of the drawing coefficient and the delta-criterion depends on the deformation parameters with intensive hardening and significant value of the friction coefficient. The possibility of the absence of limiting values of the drawing coefficient and criterion Δ under hypothetical drawing conditions is shown: intensive hardening of the wire material at low friction coefficient and the calculation of the limiting values of these indicators based on the value of the I.L. Perlin safety factor, equal to 1. The estimation of the reliability of the approximate equality is carried out to determine the nature of the relationship between the criterion Δ and the index of the deformed state. It is shown that with small value of the delta-criterion (Δ < 2) wire breakage at the die exit is not guaranteed, since the limiting value of the drawing coefficient is slightly greater than 1. The drawing production technologist needs assessment of the limiting and legitimate values of the drawing coefficient and delta-criterion for predicting of wire (rod) breakage at given deformation parameters.

Deformation Law of Cold Drawing Process of High Strength Bridge Cable Steel

2021 ◽  
Vol 1035 ◽  
pp. 801-807
Author(s):  
Xiao Lei Yin ◽  
Jian Cheng ◽  
Gang Zhao
Keyword(s):  
Strain Path ◽  
High Strength ◽  
Cold Drawing ◽  
Wire Drawing ◽  
Radial Deformation ◽  
Steel Bridge ◽  
Drawing Process ◽  
Single Pass ◽  
Potential Relationship ◽  
The Wire

High-strength cable-steel bridge is the “lifeline” of steel structure bridges, which requires high comprehensive mechanical properties, and cold-drawing is the most important process to produce high-strength cable-steel bridge. Therefore, through the ABAQUS platform, a bridge wire drawing model was established, and the simulation analysis on the process of stress strain law and strain path trends for high-strength bridge steel wire from Φ 12.65 mm by seven cold-drawing to Φ 6.90 mm was conducted. The simulation results show that the wire drawing the heart of the main axial deformation, surface and sub-surface of the main axial and radial deformation occurred, with the increase in the number of drawing the road, the overall deformation of the wire was also more obvious non-uniformity. In the single-pass drawing process, the change in the potential relationship of each layer of material was small, and multiple inflection points appeared in the strain path diagram; the change in the seven-pass potential relationship was more drastic, which can basically be regarded as a simple superposition of multiple single-pass pulls.

A Research on Key Technology in Overturn-Preventing of Longxi Tower’s Monolithic Movement

2014 ◽  
Vol 548-549 ◽  
pp. 1810-1814
Author(s):  
Dong Fan Shang ◽  
Tie Cheng Wang ◽  
Zhi Feng Yang
Keyword(s):  
Reinforced Concrete ◽  
Safety Factor ◽  
Support System ◽  
Time Shift ◽  
Protection Measures ◽  
Key Technology ◽  
Base Area ◽  
Protective Tube ◽  
Small Base ◽  
First Time

Longxi Tower is the first time shift of pagoda relics in China. All the following factors increase the difficulty of the shift: long years’ construction, serious aging of its structure, poor integrity, small base area and great height. In the process, we used steel initiative urging support system and reinforced concrete protective tube for Longxi Tower’s reinforcement protection, so as to form a stable entirety. Compared to no protection measures, overturn-preventing calculations and further reinforce protection measures improved the safety factor 6.0 times, thus greatly improving the overturn-preventing ability of Longxi Tower.

scholarly journals Influence of a modified drawing process on the resulting residual stress state of cold drawn wire

2018 ◽  
Vol 190 ◽  
pp. 04004
Author(s):  
Markus Baumann ◽  
Alexander Graf ◽  
René Selbmann ◽  
Katrin Brömmelhoff ◽  
Verena Kräusel ◽  
...  
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Wire Drawing ◽  
Industrial Applications ◽  
Drawing Process ◽  
Die Geometry ◽  
Residual Stress State ◽  
Drawing Die ◽  
Process Modification ◽  
The Wire

Torsion bars are used in automotive engineering as well as in other industrial applications. Such elements are produced by bending cold drawn wires. In conventional drawing processes tensile residual stresses occur near the surface of the wire. Small bending radii, which are required in limited assembly spaces, result in component failure due to reduced formability. Additional operations such as heat treatment or shot peening are necessary to influence the residual stress of the wire and to improve the dynamic stability of the torsion bar. The aim of the research is to reduce tensile residual stresses near the surface of the wire in order to eliminate process steps and to enhance formability. Therefore, a forming technology is developed by using a modified drawing die geometry on the basis of gradation extrusion. Finite element simulation is used to investigate the influences of element geometry, number of elements and process modification on the resulting residual stresses after wire drawing of a steel alloy. The results are evaluated and compared with the conventional wire drawing process. Furthermore, the requirements for the design of an experimental test device will be outlined as well as the measurement of the residual stresses by using X-ray diffraction.

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