Improved Extrudability of High Strength Alloys Using an Optimization Method Based on a Combination of Experiments and FEM Software

2013 ◽  
Vol 585 ◽  
pp. 165-171 ◽  
Author(s):  
Stanka Tomovic-Petrovic ◽  
Rune Østhus ◽  
Ola Jensrud

Numerical analysis of the material flow during the extrusion process for high alloyed variants of the AA 6xxx series is presented in this paper. The analysis was performed by using the commercial FE code Forge2011®. Another issue considered in the paper was an interrelation between the die geometry and the critical extrusion process variables. For optimization of the die exit geometry, the model was produced with the use of linked equation in SolidWorks® combined with Mode FRONTIER. Several extrusion trials were performed to provide a basis for the verification of simulation results as extrusion temperature, speed and force. For the purpose, rods of a model alloy designated as AlMgSi4, based on an industrial AA6082 aluminium alloy with significantly higher silicon content, were extruded. A good correlation between measured and calculated results was obtained. This approach may enable simplifying when dealing with design of a new alloy.

2008 ◽  
Vol 367 ◽  
pp. 47-54 ◽  
Author(s):  
Thomas Kloppenborg ◽  
Marco Schikorra ◽  
Michael Schomäcker ◽  
A. Erman Tekkaya

The decrease of the bearing length in extrusion processes results in increasing of the material flow and offers, through this, the possibility for manipulation and optimization. This paper presents a simulation based optimization technique which uses this effect for optimizing the material flow in direct extrusion processes. Firstly, the method is used in a multi-extrusion process with equal pitch circle profiles, then in an extrusion process of an asymmetric profile. Furthermore, a composite extrusion process is analyzed where endless wires of high strength steel are embedded in a base material of aluminum. The insertion of reinforcement elements into the base material flow, especially within the small ratio between profile thickness and the reinforcement diameter, can lead to significant local disturbances inside the die, which result in undesirable profile defects. Hence, the simulation-based optimization method is especially used to optimize inhomogeneous wall thicknesses in composite profiles.


2006 ◽  
Vol 519-521 ◽  
pp. 919-924 ◽  
Author(s):  
B.S. Ham ◽  
J.H. Ok ◽  
Jung Min Seo ◽  
Beong Bok Hwang ◽  
K.H. Min ◽  
...  

This paper is concerned with forward rod extrusion combined simultaneously with backward tube extrusion process in both steady and transient states. The analysis has been conducted in numerical manner by employing a rigid-plastic finite element method. AA 2024 aluminum alloy was selected as a model material for analysis. Among many process parameters, major design factors chosen for analysis include frictional condition, thickness of tube in backward direction, punch corner radius, and die corner radius. The main goal of this study is to investigate the material flow characteristics in combined extrusion process, i.e. forward rod extrusion combined simultaneously with backward tube extrusion process. Simulation results have been summarized in term of relationships between process parameters and extruded length and volume ratios, and between process parameters and force requirements, respectively. The extruded length ratio is defined as the ratio of tube length extruded in backward direction to rod length extruded in forward direction, and the volume ratio as that of extruded volume in backward direction to that in forward direction, respectively. It has been revealed from the simulation results that material flow into both backward and forward directions are mostly influenced by the backward tube thickness, and other process parameters such as die corner radius etc. have little influence on the volume ratio particularly in steady state of combined extrusion process. The pressure distributions along the tool-workpiece interface have been also analyzed such that the pressure exerted on die is not so significant in this particular process such as combined operation process. Comparisons between multi-stage forming process in sequence operation and one stage combined operation have been also made in terms of forming load and pressure exerted on die. The simulation results shows that the combined extrusion process has the greatest advantage of lower forming load comparing to that in sequence operation.


2006 ◽  
Vol 519-521 ◽  
pp. 955-960 ◽  
Author(s):  
Dong Hwan Jang ◽  
J.H. Ok ◽  
G.M. Lee ◽  
Beong Bok Hwang

Numerical analysis of radial extrusion process combined with backward extrusion has been performed to investigate the forming characteristics of an aluminum alloy in a combined extrusion process. Various variables such as gap size, die corner radius and frictional conditions are adopted as design or process parameters for analysis in this paper. The main investigation is focused on the analysis of forming characteristics of AA 2024 aluminum alloy in terms of material flow into backward can and radial flange sections. Due to various die geometries and process conditions such as frictional conditions, the material flow into a can and flange shows different patterns during the combined extrusion process and its characteristics are well summarized quantitatively in this paper in terms of forming load, volume ratio etc. Extensive simulation work leads to quantitative relationships between process conditions and the forming characteristics such as volume ratio of flange to can and the size of can and flange in terms of the can height extruded backward. It is easily seen from the simulation results that the volume ratio, which is defined as the ratio of flange volume to can volume, increases as the gap size and/or die corner radius increase. However, it is interesting to note that the frictional condition has little influence on the forming load and the deformation patterns. Usually, the frictional condition is a greatest process variable in normal forging operation. It might be believed from the simulation results that the frictional conditions are not a major process parameter in case of combined extrusion processes. It is also found that the can size, which is defined as the height of billet after forming, turns out to be even smaller than that of initial billet under a certain condition of die geometry.


2014 ◽  
Vol 926-930 ◽  
pp. 3521-3526
Author(s):  
Tian Xiao Chen ◽  
Chun Mei Li ◽  
Nan Pu Cheng ◽  
Hui Na Jia

The direct extrusion process by using a newly designed die with different angle and feeder plate numbers has been simulated to systematically investigate the effects of different geometric parameters angle and feeder plate number on the strain distribution, the load and the axial hole defect. The simulation results show that the extrusion process with multiple feeder plate die is similar to that of the extrusion for many times. The angle and feeder plate make the material flow more fluently and ameliorate the axial hole defect. The larger angle reduces the load while the feeder plate increases it. Suitable geometrical parameters can significantly enhance strain in workpiece.


2013 ◽  
Vol 554-557 ◽  
pp. 787-793 ◽  
Author(s):  
Martin Schwane ◽  
Francesco Gagliardi ◽  
Andreas Jäger ◽  
Nooman Ben Khalifa ◽  
A. Erman Tekkaya

The material flow in porthole dies is of crucial importance with regard to the seam weld quality in aluminum extrusion. Thus, experimental as well as numerical investigations on the effect of die geometry on the material flow were conducted. The experimental tests were performed on a 10 MN laboratory extrusion press. During the experimental trials, the extrusion ratio was varied by means of exchangeable die plates. Since the modular die allows removal of the aluminum in the welding chamber as well as in the feeders after the process, the material flow could be inspected in detail. The experimental results were used to improve the accuracy of FEA simulations, which were also conducted by commercial software. An attempt was made to improve the result quality of Eulerian FEA model regarding the simulation of an extrusion process with a gas pocket in the welding chamber. The influence of the modeling approach on the predicted material flow and on the contact pressure was analyzed and finally linked to the seam weld quality.


2008 ◽  
Vol 43 ◽  
pp. 9-16 ◽  
Author(s):  
Daniel Pietzka ◽  
Marco Schikorra ◽  
A. Erman Tekkaya

Extruded aluminum profiles are essential for lightweight constructions in contemporary transport and automotive applications. The reinforcement of such aluminum-based profiles with high-strength materials offers a high potential for weight reduction and an improvement of functional and mechanical properties. In comparison to conventional composite extrusion using fiber or particle reinforced billets, the alternatively developed process for the embedding of endless reinforcing elements provides enormous advantages regarding extrusion forces, load-adapted reinforcement, and tool abrasion. In this extrusion process with conventional billets, modified tools with portholes are used to position reinforcing elements from outside the pressing tool and to embed them into the material flow during the pressing operation. This composite extrusion process is part of the research work started in 2003 and carried out within the scope of the Collaborative Research Center SFB/TR10. To increase the potential of composite extrusion with endless reinforcing elements, the manufacture of composite extrusion profiles with high-strength non-metallic alumina wires is planned. Due to the wires’ specific properties, e.g. high stiffness, their deflection behavior must be analyzed to guarantee a stable feeding-in process. In this paper the specific behavior of alumina reinforcing elements regarding the feeding-in process is analyzed by experimental investigations. The main influencing factors are determined and a process window is deduced.


Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 513 ◽  
Author(s):  
Tuncay Yalçinkaya ◽  
Ülke Şimşek ◽  
Hiroyuki Miyamoto ◽  
Motohiro Yuasa

Severe plastic deformation (SPD) can produce ultrafine grained (UFG) and nanocrystalline (NC) materials by imposing intense plastic strain. One of the many options for inducing large plastic strains is to pass the material through a torsional/twist extrusion. The high-strength materials fabricated by SPD has no limit in dimension, and they can even be applied to load-carrying structural materials. Even though the method is quite successful, the industrial transfer has been limited so far because of low production efficiency and high cost. To remedy such difficulties, a new torsional extrusion process called nonlinear twist extrusion (NLTE) is introduced in this study, which has been designed based on two principles; (1) linear arrangement of the production line and (2) effective die geometry resulting in higher and more homogeneous plastic strain evolution which would give better grain refinement. The initial computational study of the designed geometry for the new extrusion process is addressed in the current study. The obtained results are discussed in detail with respect to conventional extrusion process, which is referred to as linear twist extrusion (LTE). The method is expected to offer a great potential for industrial use.


2006 ◽  
Vol 519-521 ◽  
pp. 931-936 ◽  
Author(s):  
J.H. Ok ◽  
Beong Bok Hwang

This paper is concerned with the analysis on the surface expansion of AA 2024 and AA 1100 aluminum alloys in backward extrusion process. Due to heavy surface expansion appeared usually in the backward can extrusion process, the tribological conditions along the interface between the material and the punch land are very severe. In the present study, the surface expansion is analyzed especially under various process conditions. The main goal of this study is to investigate the influence of degree of reduction in height, geometries of punch nose, friction and hardening characteristics of different aluminum alloys on the material flow and thus on the surface expansion on the working material. Two different materials are selected for investigation as model materials and they are AA 2024 and AA 1100 aluminum alloys. The geometrical parameters employed in analysis include punch corner radius and punch face angle. The geometry of punch follows basically the recommendation of ICFG and some variations of punch geometry are adopted to obtain quantitative information on the effect of geometrical parameters on material flow. Extensive simulation has been conducted by applying the rigid-plastic finite element method to the backward can extrusion process under different geometrical, material, and interface conditions. The simulation results are summarized in terms of surface expansion at different reduction in height, deformation patterns including pressure distributions along the interface between workpiece and punch, comparison of surface expansion between two model materials, geometrical and interfacial parametric effects on surface expansion, and load-stroke relationships. It has been concluded from the present study that the geometrical condition of punch is the most significant factor among the parameters employed in this study. It is also known from the simulation results that the difference in surface expansion according to different material properties is not more or less significant.


Author(s):  
Hanliang Zhu ◽  
Malcolm J. Couper ◽  
Arne K. Dahle

AbstractStreak defects are often present on anodized extrusions of 6xxx series aluminum alloys, increasing the fabrication cost of these products. Moreover, streaking often only becomes visible after etching and anodizing treatments, rather than in the as-extruded condition, making it difficult to identify the original causes and influencing factors of these defects. In this paper, various process variables that influence the formation of streak defects on anodized aluminium extrusions are reviewed on the basis of a literature review, industrial practice and experimental results. The influencing factors involved in various processing steps such as billet quality, extrusion process, die design and etching process are considered. Effective measures for preventing the formation of streak defects in industrial extrusion products are discussed.


2011 ◽  
Vol 189-193 ◽  
pp. 1778-1781 ◽  
Author(s):  
Gui Hua Liu ◽  
Yong Qiang Guo ◽  
Zhi Jiang

By using Deform-3D software, the necking extrusion forming processes of integer trailer axle with two different heating means which are Uniform Heating (UH) method and Partly Heating (PH) method with temperature gradient are simulated. The influence of deformation parameters such as friction factor, necking coefficient, different temperature distribution of work-piece on the material flow features, stress and strain field, loading force and deformation process are analyzed in detail. According to the numerical simulation results, using PH method with temperature gradient can improve necking deformation during tube extrusion process.


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