Numerical and experimental study of the effect of the process parameters on the void evolution in the cold extrusion of rods

Document Type : Article


Department of Mechanical Engineering , Babol Noshirvani University of Technology, Babol, Iran.


Elimination of defects such as voids and internal cavities is required in metal forming processes to avoid premature failure of mechanical components during service. In this paper, the effect of different parameters on the void closure behavior is studied in the cold extrusion of rods. A three dimensional nonlinear dynamic finite element model is developed for this purpose. Experiments are also performed on aluminum samples to verify the accuracy of the finite element model. Results of the developed model are in good agreement with experimental findings. It is observed that voids contract in all directions during the direct extrusion which is in contrast to some other metal forming processes like forging and rolling. Effect of parameters such as die semi-angle, friction coefficient and void location on the void evolution is systematically investigated and discussed. The results of this study can help industries using metal extrusion for optimized design and control of the process to reduce voids and porosity and increase the strength of their product.


Main Subjects

1. Chen, M.-S., Lin, Y.C., and Chen, K.-H. "Evolution ofn elliptic-cylindrical and circular-cylindrical voids inside power-law viscous solids", Int. J. Plast., 53(1), pp. 206-227 (2014).
2. Vladimirov, I. N., Pietryga, M.P., Kiliclar, Y., Tini, V.,and Reese, S. "Failure modelling in metal forming by means of an anisotropic hyperelastic-plasticity model with damage", Int. J. Damage Mech., 23(8), pp. 1096-
1132 (2014).
3. Saby, M., Bernacki, M., and Bouchard, P.-O. "Understanding and modeling of void closure mechanisms in hot metal forming processes: A multiscale approach", Procedia Eng., 81(1), pp. 137-142 (2014).
4. Kittner, K., Wiesner, J., and Kawalla, R. "A new approach for void closure in bulk metal forming", Key Eng. Mater., 716(3), pp. 595-604 (2016).
5. Patel, M., Kim, H.-S., Park, H.-H., and Kim, J."Active adoption of void formation in metal-oxide for all transparent super-performing photodetectors", Sci.Rep., 6(2), p. 25461 (2016).
6. Saby, M., Bouchard, P.-O., and Bernacki, M. "A geometry-dependent model for void closure in hot metal forming", Finite Elem. Anal. Des., 105(4), pp.63-78 (2015).
7. Saby, M., Bouchard, P.-O., and Bernacki, M. "Void closure criteria for hot metal forming: A review", J. Manuf. Process., 19(1), pp. 239-250 (2015).
8. Chen, J., Chandrashekhara, K., Mahimkar, C., Lekakh, S.N., and Richards, V.L. "Void closure prediction in cold rolling using finite element analysis and neural network", J. Mater. Process. Technol., 211(2),
pp. 245-255 (2011).
9. Kakimoto, H., Arikawa, T., Takahashi, Y., Tanaka, T., and Imaida, Y. "Development of forging process design to close internal voids", J. Mater. Process. Technol., 210(3), pp. 415-422 (2010).
10. Huang, G., Han, Y., Guo, X., Qiu, D., Wang, L., Lu, W., and Zhang, D. "Eects of extrusion ratio on microstructural evolution and mechanical behavior of in situ synthesized Ti-6Al-4V composites", Mater. Sci.
Eng. A., 688(1), pp. 155-163 (2017).
11. Kim, Y., Cho, J., and Bae, W. "Efficient forging process to improve the closing eect of the inner void on an ultra-large ingot", J. Mater. Process. Technol., 211(6), pp. 1005-1013 (2011).
12. Chen, K., Yang, Y., Shao, G., and Liu, K. "Strain function analysis method for void closure in the forging process of the large-sized steel ingot", Comput. Mater.Sci., 51(1), pp. 72-77 (2012).
13. Chen, J., Chandrashekhara, K., Mahimkar, C., Lekakh, S.N., and Richards, V.L. "Study of void closure in hot radial forging process using 3D nonlinear finite element analysis", Int. J. Adv. Manuf. Technol., 62(9), pp. 1001-1011 (2012).
14. Chen, M.-S. and Lin, Y.C. "Numerical simulation and experimental verification of void evolution inside large forgings during hot working", Int. J. Plast., 49(2), pp. 53-70 (2013).
15. Park, J.-J. "Finite-element analysis of cylindrical-void closure by  at-die forging", ISIJ Int., 53(8), pp. 1420- 1426 (2013).
16. Saby, M., Bernacki, M., Roux, E., and Bouchard, P.- O. "Three-dimensional analysis of real void closure at the meso-scale during hot metal forming processes", Comput. Mater. Sci., 77(3), pp. 194-201 (2013).
17. Saboori, M., Bakhshi-Jooybari, M., Noorani-Azad, M., and Gorji, A. "Experimental and numerical study of energy consumption in forward and backward rod extrusion", J. Mater. Process. Technol., 177(1), pp. 612-616 (2006).
18. Noorani-Azad, M., Bakhshi-Jooybari, M., Hosseinipour, S.J., and Gorji, A. "Experimental and numerical study of optimal die profile in cold forward rod extrusion of aluminum", J. Mater. Process. Technol., 164(2), pp. 1572-1577 (2005).
19. Bakhshi-Jooybari, M., Saboori, M., Noorani-Azad, M., and Hosseinipour, S.J. "Combined upper bound and slab method, finite element and experimental study of optimal die profile in extrusion", Mater. Des., 28(6), pp. 1812-1818 (2007).
20. Koc, M., Hydroforming for Advanced Manufacturing, Elsevier (2008). 21. Palumbo, G., Sorgente, D., and Tricarico, L. "A numerical and experimental investigation of AZ31 formability at elevated temperatures using a constant strain rate test", Mater. Des., 31(3), pp. 1308-1316 (2010).
22. Chen, D.-C., Chang, D.-Y., Chen, F.-H., and Kuo, T.- Y. "Application of ductile fracture criterion for tensile test of zirconium alloy 702", Sci. Iran., 25(2), pp. 824- 829 (2018).
23. A Nurul, M. and Syahrullail, S. "A new approach for cold extrusion process: Dimples indentation on sliding contact surface and palm oil as an alternative lubricant", Sci. Iran., 24(6), pp. 2875-2886 (2017).
24. Saha, P.K. "Aluminum extrusion technology", ASM International: Materials Park, 1(3), pp. 112-115 (2000).