Determination of Geometrical Parameters of the Dead Metal Zone and Exit Curvature Profile in the Extrusion Process of Non-Symmetrical Flat Dies

2012 ◽  
Author(s):  
Meysam Rastegar ◽  
Ahmad Assempour ◽  
Amir Ghazanfari
Keyword(s):  
Extrusion Process ◽  
Geometrical Parameters ◽  
Dead Metal Zone ◽  
The Dead

Effect of Strain Rate on Metal Flow Pattern in T-Section Extrusion Process

2011 ◽  
Vol 491 ◽  
pp. 241-247 ◽  
Author(s):  
Pouria Homayoun ◽  
Mostafa Ketabchi
Keyword(s):  
Strain Rate ◽  
Flow Pattern ◽  
Deformation Process ◽  
Final Section ◽  
Metal Flow ◽  
Extrusion Process ◽  
Specimen Height ◽  
Dead Metal Zone ◽  
Intermediate Section ◽  
The Dead

Extrusion is a deformation process used in metal sections fabrication. Metal flow pattern during extrusion process is of great importance. How circular initial section of billet changes to final section provides more details of extrusion process, and plays an important role in optimizing the extrusion energy. Extrusion in flat-faced die, without intermediate section, needs much more energy than is required for die having intermediate section. The aim of this study was to investigate the effect of strain rate on metal flow pattern in T-section extrusion process. Four different ram speeds were applied to realize how the shape and position of intermediate section would be affected. Flat-faced die with “T” final section was designed and manufactured. Straight layout of metal was of top concern in die design. Commercial purity aluminum, Al 99.5, was extruded in flat-faced die in hot condition. Graphite was used as lubricant in deformation process. After partial extrusion of billets, the residual part of billets pounced out of container and then mounted for metallographic tests. This part of billets consisted of dead-metal zone and deformation zone. Then, step-by-step decreasing of specimen height followed by macro-etching of metal surface paved the way for determining the metal flow pattern. An egg-shaped intermediate section appeared between initial round section and final “T” section. The size and position of the intermediate section changed by varying the strain rate of extrusion process; It was also revealed that as the strain rate of extrusion process is increased, the dead-metal zones become narrower and the dead-metal zone semi angle increases.

scholarly journals Mathematical Model Describing the Influence of Geometrical Parameters of Multichannel Dies on the Limit Force of Dry Ice Extrusion Process

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3317
Author(s):  
Jan Górecki ◽  
Krzysztof Talaśka ◽  
Krzysztof Wałęsa ◽  
Dominik Wilczyński ◽  
Dominik Wojtkowiak
Keyword(s):  
Mathematical Model ◽  
Compressive Force ◽  
Extrusion Process ◽  
Physical Characteristics ◽  
Geometrical Parameters ◽  
Actual Measurement ◽  
Dry Ice ◽  
Measurement Results ◽  
The Difference

The article presents a formulated mathematical model that enables the determination of the required compressive force in the extrusion process of dry ice employing multichannel dies. This is the main parameter in the piston-based dry ice extrusion process. The indicated model was developed for the purpose of further improvement of the energy efficiency of this extrusion process. It allows for the determination of the value of compressive force by accounting for 12 variables related to the geometrical parameters of the die and the physical characteristics of dry ice. Furthermore, the paper also provides descriptions of the empirical study methodologies together with the results. These were carried out in order to determine the difference between the results of mathematical modeling and actual measurement results. The final part of the article presents the results of the analysis of the mathematical model’s sensitivity to the change of the physical characteristics of dry ice. The formulated tool may be employed to adapt the geometric parameters of the die in order to obtain the desired compressive force value and dry ice granulation with reduced energy consumption.

scholarly journals Features of the Surface and Subsurface Waves Application for Ultrasonic Evaluation of Physicomechanical Properties of Solids. Part 1. Influence of the Geometrical Parameters

2018 ◽  
Vol 9 (4) ◽  
pp. 325-326
Author(s):  
A. R. Baev ◽  
A. L. Mayorov ◽  
M. V. Asadchaya ◽  
V. N. Levkovich ◽  
K. G. Zhavoronkov
Keyword(s):  
Protective Coating ◽  
Layer Structure ◽  
Base Material ◽  
Protective Layer ◽  
Body Waves ◽  
Measuring System ◽  
Geometrical Parameters ◽  
Small Aperture ◽  
Ultrasonic Evaluation

Application of surface and subsurface waves for control of objects with a double-layer structure allows to extend possibilities of diagnostics of their physico-mechanical properties. The purpose of work was to determine conditions and offer recommendations providing measuring of ultrasonic velocity and amplitude of the former modes in protective layers and in basis of object at one-sided access to its surface.The analysis of an acoustic path of a measuring system in relation to ultrasonic evaluation of the objects having the restricted sizes and the protective coating according to velocity data of the surface and subsurface waves propagation is made. On the basis of representations of beam acoustics the dependences connecting a wavelength of the excited surface and subsurface modes, thickness and width of a controlled object, acoustic base of a sounding are defined. There are to provide a condition leveling of the influence of an acoustical noise created by the reflected and accompanying waves on parameters of acoustic signal with the given quantity of oscillations in an impulse.The principle opportunity is shown and conditions for determination of velocity of subsurface body waves in the base material which is under a protective coating layer are established. For these purposes on the basis of use of the block of ultrasonic probes the optimum scheme of a sounding is offered and the analytical expression for calculation of required velocity considering varying of thickness of a covering is received.The method of acoustical measuring realized by a direct and reverse sounding of the objects with small aperture and angle probes was analysed and formulas for determination of speed of subsurface wave under protective layer of the wedge form have been got. An ultrasonic device is suggested for the excitationreception of subsurface waves with different speed in objects (on 20–35 %) using for the acoustic concordance of environments of metallic sound duct as a wedge. Possibility of leveling of interference in a protective layer to control efects in basis of material by a volume wave by creation of supporting echo-signal of longitudinal wave of the set frequency and entered normally to the surface of object was studied.

Complete Williams Asymptotic Expansion near the Crack Tips of Collinear Cracks of Equal Lengths in an Infinite Plane

2016 ◽  
Vol 258 ◽  
pp. 209-212 ◽  
Author(s):  
Larisa Stepanova ◽  
Pavel Roslyakov ◽  
Tatjana Gerasimova
Keyword(s):  
Plane Elasticity ◽  
Analytical Determination ◽  
Geometrical Parameters ◽  
Infinite Plane ◽  
Variable Theory ◽  
Complex Variable Theory ◽  
Plane Medium ◽  
Crack Tips ◽  
Plane Elasticity Theory

The present study is aimed at analytical determination of coefficients in crack tip expansion for two collinear finite cracks of equal lengths in an infinite plane medium. The study is based on the solutions of the complex variable theory in plane elasticity theory. The analytical dependence of the coefficients on the geometrical parameters and the applied loads for two finite cracks in an infinite plane medium is given. It is shown that the effect of the higher order terms of the Williams series expansion becomes more considerable at large distances from the crack tips. The knowledge of more terms of the stress asymptotic expansions allows us to approximate the stress field near the crack tips with high accuracy.

COMPREHENSIVE INVESTIGATION OF EXTRUSION OF П-SHAPED BRACKETS. REPORT 6. KINEMATIC AND STRESSED STATES OF BLANKET DURING RESTRICTED EXTRUSION. PART 2

2021 ◽  
pp. 38-43
Author(s):  
A. L. Vorontsov ◽  
◽  
S. M. Karpov ◽  
Keyword(s):  
Plastic Deformation ◽  
Plastic Flow ◽  
Plane Deformation ◽  
Flow Theory ◽  
Equation System ◽  
Extrusion Process ◽  
Thick Wall ◽  
Comprehensive Investigation ◽  
Flow Velocities

On the basis of the complete equation system of the plastic flow theory, the solution continuation of the determination problem of the kinematic and stressed states of a blanket during restricted extrusion of П-shaped brackets under conditions of plane deformation in the general case of a nonaligned placement of the punch and the die is stated. The determination of flow velocities and stresses in the area of plastic deformation, located under the punch end near the formed thick wall of the bracket has been carried out. The formulae were obtained, which are required for identification of the main parameters of the extrusion process of П-shaped products with a relatively thin horizontal bridge.

scholarly journals The effect of column and temperature variation on the determination of the dead time in gas chromatographic systems using indirect methods

Heliyon ◽  
2020 ◽  
Vol 6 (2) ◽  
pp. e03302
Author(s):  
Rinaldi Idroes ◽  
Muslem ◽  
Mahmudi ◽  
Saiful ◽  
Ghazi Mauer Idroes ◽  
...  
Keyword(s):  
Temperature Variation ◽  
Dead Time ◽  
Indirect Methods ◽  
The Dead
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