An investigation into the effective parameters in optimal design of ECAP-Conform process of commercially pure titanium using statistical and numerical approaches

Document Type : Article


1 Department of Mechanical Engineering, University of Birjand, Birjand, Iran

2 Faculty of Mechanical and Mechatronics Engineering, Shahrood University of Technology, Shahrood, P.O. Box 3619995161, Iran


The Equal Channel Angular Pressing-Conform process has improved the mechanical and functional properties of materials as well as resolves the disadvantages of conventional ECAP. The main goal of this study was investigation of the variable in ECAP-Conform process of pure titanium Grade 2. The design of experiments with full factorial technique was implemented in conjunction with finite element numerical simulation. The equivalent plastic strain, required torque, applied force on the ECAP die, and the warping radius of the product were measured and results were interpreted using analysis of variance. It was found that the ECAP die angles and the rod bending angle have the highest effect on both imposed strain and required torque. Also, the rod bending angle and the rod-die friction had no significant effect on the warping radius. The optimal values were specified for minimizing the required torque, reaction force, and warping radius, and maximizing the imposed strain. Based on the optimal estimated parameters, the minimum values of torque, force, warping radius, and maximum value of equivalent strain were predicted to 8.4 kN.m, 42 kN, 0.36 m, and 1.7, respectively. Also, the response optimizer obtained the results with less than 8% error in comparison with numerical simulation.


1. Shaat, M. "Effects of processing conditions on microstructure and mechanical properties of equalchannel-angular-pressed titanium", Mater. Sci. Technol., 34(10), pp. 1149-1167 (2018).
2. Horita, Z., Nemoto, M., and Langdon, T.G. "An investigation of microstructural evolution during equalchannel angular pressing", Acta Mater., 45(11), pp. 4733-4741 (1997).
3. Frint, S., Hockauf, M., Frint, P., et al. "Scaling up segal's principle of equal-channel angular pressing", Mater. Des., 97, pp. 502-511 (2016).
4. Raab, G.J., Valiev, R.Z., Lowe, T.C., et al. "Continuous processing of ultrafine grained al by ECAPconform", Mater. Sci. Eng. A., 382(1-2), pp. 30-34 (2004).
5. Volokitina, I., Volokitin, A., Naizabekov, A., et al. "FEM-study of bimetalic wire deformation during combined ECAP-drawing", J. Chem. Technol. Metall., 56(2), pp. 410-416 (2021).
6. Krajnak, T., Janecek, M., Minarik, P., et al. "Microstructure evolution and mechanical properties of CP-Ti processed by a novel technique of rotational constrained bending", Metall. Mater. Trans. A., 52(5), pp. 1665-1678 (2021).
7. Akbarzadeh, B., Gorji, H., Bakhshi-Jooybari, M., et al. "Investigation of mechanical and microstructural properties of pure copper processed by combined extrusionequal channel angular pressing (C-Ex-ECAP)", Int. J. Adv. Manuf. Technol., 113(7-8), pp. 2175-2191 (2021).
8. Etherington, C. "Conform-a new concept for the continuous extrusion forming of metals", J. Eng. Ind., 96(3), pp. 893-900 (1974).
9. Raab, G.I., Valiev, R., Gunderov, D., et al. "Longlength ultrafine-grained titanium rods produced by ECAP-conform", Mater. Sci. Forum, 584-586, pp. 80-85 (2008).
10. Hoppel, H., Kautz, M., Murashkin, M., et al. "An overview: Fatigue behaviour of ultrafine-grained metals and alloys", Int. J. Fatigue, 28(9), pp. 1001-1010 (2006).
11. Ayati, V., Parsa, M.H., and Mirzadeh, H. "Deformation of pure aluminum along the groove path of ECAPConform process", Adv. Eng. Mater., 18(2), pp. 319- 323 (2016).
12. Derakhshan, J.F., Parsa, M.H., and Jafarian,  .R. "Microstructure and mechanical properties variations of pure aluminum subjected to one pass of ECAPConform process", Mater. Sci. Eng. A., 747, pp. 120- 129 (2019).
13. Murashkin, M.Y., Medvedev, A.E., Kazykhanov, V.U., et al. "Microstructure, strength, electrical conductivity and heat resistance of an Al-Mg-Zr alloy after ECAP-Conform and cold drawing", Rev. Adv. Mater. Sci., 47(1-2), pp. 16-25 (2016).
14. Morozova, A., Lugovskaya, A., Pilipenko, A., et al. "Microstructure of a low alloyed Cu-Cr-Zr alloy after ECAP-Conform", IOP Conf. Ser. Mater. Sci. Eng., 1014, p. 012029 (2021).
15. Shahab, A.R., Akbari Mousavi, S.A.A., Ranjbar Bahadori, S., et al. "The comparison between continuous confined strip shearing (C2S2) and ECAP conform in regard to equivalent plastic strain distribution for Al 1100", Int. J. Mod. Phys. Conf. Ser., 05, pp. 400-409 (2012).
16. Gholami, J., Pourbashiri, M., and Sedighi, M. "Effect of channel angle and friction in modified ECAPConform Process of Al-6061: A numerical study", Iran. J. Mater. Sci. Eng., 12(4), pp. 71-76 (2015).
17. Prochazka, R., Slama, P., Dlouhy, J., et al. "Local mechanical properties and microstructure of EN AW 6082 aluminium alloy processed via ECAP-Conform technique", Materials (Basel), 13(11), p. 2572 (2020).
18. Ghaforian Nosrati, H., Khalili, K., and Gerdooei, M. "Theoretical and numerical investigation of required torque in ECAP-Conform process", Metall. Mater. Trans. B., 51(2), pp. 519-528 (2020).
19. Ghaforian Nosrati, H., Khalili, K., and Gerdooei, M. "Theoretical and experimental evaluation of noslip feeding condition in ECAP-Conform of a squaresection metallic rod", Int. J. Adv. Manuf. Technol., 112(1-2), pp. 375-385 (2021).
20. Iwahashi, Y., Wang, J., Horita, Z., et al. "Principle of equal-channel angular pressing for the processing of ultra-fine grained materials", Scr. Mater., 35(2), pp. 143-146 (1996).
21. Marciniak, Z., Duncan, J.L., and Hu, S.J. "6-bending of sheet BT-mechanics of sheet metal forming (second edition)", Butterworth-Heinemann, Oxford, pp. 82- 107 (2002).
22. Furukawa, M., Horita, Z., Nemoto, M., et al. "Review: Processing of metals by equal-channel angular pressing", J. Mater. Sci., 36(12), pp. 2835-2843 (2001).
23. Montgomery, D.C., Design and Analysis of Experiments, John Wiley & Sons (2017).
24. Freddi, A. and Salmon, M. "Design principles and methodologies: Design of experiment", In Springer Tracts in Mechanical Engineering, pp. 127-158 (2019).