Analysis and die design of flat-die hot extrusion process 2. Numerical design of bearing lengths

2002 ◽  
Vol 44 (5) ◽  
pp. 935-946 ◽  
Author(s):  
Geun-An Lee ◽  
Yong-Taek Im
Author(s):  
Nooman Ben Khalifa ◽  
A. Erman Tekkaya

A new innovative direct extrusion process, helical profile extrusion (HPE) is presented, which increases the flexibility of aluminum profile manufacturing processes. The application fields of such profiles can be seen in screw rotors for compressors and pumps. The investigations concentrate on experimental and numerical analyses by 3D-FEM simulations to analyze the influence of friction and the material flow on the twisting angle and contour accuracy. By means of finite-element method (FEM), the profile shape could be improved by modifying the die design. The numerical results were validated by experiments. For these investigations, a common aluminum alloy AA6060 was used. Mainly, the friction in the die influences the twist angle and the shape of the helical profile. Two die coatings were analyzed, but the friction was not substantially decreased in any of these cases. Although there is no efficient practical solution for reducing the friction in extrusion dies using tested die coatings, the required profile contour could be achieved by new die designing and by modifying the material flow. However, increasing the twist angle is limited due to geometrical aspects of this technology, namely, by the ratio of the volume to the contact area with the die for the displaced metal.


Author(s):  
Nooman Ben Khalifa ◽  
A. Erman Tekkaya

The paper presents a new innovative direct extrusion process, Helical Profile Extrusion (HPE), which increases the flexibility of aluminum profile manufacturing processes. The application fields of such profiles can be seen in screw rotors for compressors and pumps. The investigations concentrate on experimental and numerical analyses by 3D-FEM simulations to analyze the influence of friction on the material flow in the extrusion die in order to find out the optimal parameters with reference to the twisting angle and contour accuracy. By means of FEM, the profile shape could be optimized by modifying the die design. The numerical results were validated by experiments. For these investigations, a common aluminum alloy AA6060 was used. The accuracy of the profile contour could be improved significantly. However, increasing the twist angle is limited due to geometrical aspects.


2010 ◽  
Vol 443 ◽  
pp. 98-103 ◽  
Author(s):  
Yeong-Maw Hwang ◽  
Shih Ming Tu

This study involves analyses and experiments of hot extrusion of magnesium alloy strips. Hot compression tests were firstly conducted to obtain the magnesium alloy’s plastic flow stresses at high temperatures. These data are used in the finite element simulations of the thin strip extrusion process. Using the FE simulations, the flow pattern of the magnesium alloy billet within the die, the temperature variation and the thickness distribution at the die exit were analyzed. The effects of different die bearing height design, initial billet temperatures and ram speed on the extrusion load, the temperature at the die exit and the product thickness distribution were also discussed. Finally, hot extrusion experiments were conducted and the experimental values of the extrusion load and dimensions of the products were compared with the analytical values to validate the analytical model. Sound products were obtained using the best designed bearing heights and other appropriate extrusion conditions.


Author(s):  
A. Damodar Reddy ◽  
P.N. Karthikeyan ◽  
S. Krishnaraj ◽  
Adarsh Ajayan ◽  
K. Sunil Kumar Reddy ◽  
...  

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 663
Author(s):  
Thomas Borgert ◽  
Werner Homberg

Modern forming processes often allow today the efficient production of complex parts. In order to increase the sustainability of forming processes it would be favorable if the forming of workpieces becomes possible using production waste. At the Chair of Forming and Machining Technology of the Paderborn University (LUF) research is presently conducted with the overall goal to produce workpieces directly from secondary aluminum (e.g., powder and chips). Therefore, friction-based forming processes like friction spinning (or cognate processes) are used due to their high efficiency. As a pre-step, the production of semi-finished parts was the subject of accorded research work at the LUF. Therefore, a friction-based hot extrusion process was used for the full recycling or rework of aluminum chips into profiles. Investigations of the recycled semi-finished products show that they are comparable to conventionally produced semi-finished products in terms of dimensional stability and shape accuracy. An analysis of the mechanical properties of hardness and tensile strength shows that a final product with good and homogeneously distributed properties can be produced. Furthermore, significant correlations to the friction spinning process could be found that are useful for the above-mentioned direct part production from secondary aluminum.


2015 ◽  
Vol 817 ◽  
pp. 531-537 ◽  
Author(s):  
Tao Tang ◽  
Yi Chuan Shao ◽  
Da Yong Li ◽  
Ying Hong Peng

In order to study the influence of extrusion process on texture development of alloys, numerical simulation methods were used to simulate the round and shape extrusion process and deformation texture. Extrusion of Mg-Y magnesium alloy was carried out at the temperature of 673K with different ram speeds to verify the simulation results. Instead of using the Lagrangian FE method, the Arbitrary Lagrangian-Eulerian (ALE) method was employed in this study so that a more accurate description of the steady-state extrusion process can be achieved. By obtaining strain histories of specified material tracer particles, the coupling of deformation and crystal plasticity theory was applied to simulate the texture evolution in hot extrusion. The results showed that the texture simulation corresponded well with the experimental ones. The study proposes a method to analyze the steady-state extrusion process and texture evolution, and can be used as a useful tool in optimizing the extrusion process.


2021 ◽  
Author(s):  
Riccardo Pelacci ◽  
Marco Negozio ◽  
Barbara Reggiani ◽  
Lorenzo Donati ◽  
Luca Tomesani

Liquid nitrogen cooling is widely used in the extrusion industrial practice in order to increase the production rate, to reduce the die temperature and to avoid defects on the profile exit surfaces resulting from an excessive heating. However, the efficiency of the cooling is deeply affected by position and design of the liquid nitrogen channel so that numerical modelling is gaining an increasing industrial interest in relation to the possibility offered to optimize the channel design without expensive and time-consuming experimental trials. In this work, a numerical FE model developed within COMSOL Multiphysics® is proposed and validated against experimental trials performed in industrial environment. The model combines the 3D simulation of the extrusion process with a 1D model of the cooling channel thus allowing the testing of a number of different solutions at the die design stage. The global aim of this work is the assessment of the liquid nitrogen cooling efficiency in the extrusion of an industrial aluminum profile and the proof of the potentials offered by numerical models to get an optimized channel design in terms of cooling efficiency, die thermal balancing and reduction of liquid nitrogen consumption.


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