Ural Federal University named after the first President of Russia B. N. Yeltsin, Ekaterinburg, Russia:

Yu. N. Loginov, Professor, e-mail: j.n.loginov@urfu.ru
A. Yu. Postylyakov, Post-Graduate Student
Yu. V. Inatovich, Assistant Professor

The process of copper bar rolling in a box groove is the object of the study. Strain scheme corresponds to the production process CONTIROD. Evaluation of the stress-strain state used the finite elements method, implemented in a software module DEFORM-3D. Distribution of the strain degree, standard pressure, middle and longitudinal stresses was obtained, and heterogeneity of these parameters is shown over the size of the deformable metal. Zones of increased strain degree are located on the edge of the bar and are extended deep into it in the form of the forging cross. Diagrams of distribution of medium and longitudinal stress on the trajectory of the points, located on the bar side, are drawn. Compressive stress is observed in the non-contact zone before the entry of the rolling. Stress is replaced by the pulling inside the strain center. After the rolling process, stress becomes compressive again in the non-contact zone. The bar pressing process starts on the edges and extends toward the center. The metal zones, placed closer to the edges, are under the bigger strain in strain center on the side. The area of the potentially dangerous pulling stress was defined in the central part of the side surface of the bar. The practical significance of the calculations is to determine the billet areas, where the metal destruction is possible. It is necessary to use the strain scheme during the profiled rolling, characterized by low level of pulling stress, since the copper billet rolling practice shows the possibility of occurrence of cracks on the side.

1. Loginov Yu. N., Maltseva L. A., Vyrlina L. M., Kopylova T. P. Anizotropnye svoystva nepreryvnolitoy mednoy katanki elektrotekhnicheskogo naznacheniya (Anisotropy properties of continuous-cast copper rod of electrotechnical purpose). Tsvetnye Metally = Non-ferrous metals. 2002. No. 4. pp. 73–77.
2. Bobylev A. V. Mekhanicheskie i tekhnologicheskie svoystva metallov : spravochnik (Mechanical and technological properties of metals : reference book). Moscow : Metallurgiya, 1987. 208 p.
3. Hirt G., Senge S. Selected processes and modeling techniques for rolled products. Procedia Engineering. 2014. Vol. 81. pp. 18–27.
4. Gao W., Belyakov A., Miura H., Sakai T. Dynamic recrystallization of copper polycrystals with different purities. Materials Science and Engineering A. 1999. Vol. 265, iss. 1–2. pp. 233–239.
5. Ervasti E., Ståhlberg U. Void initiation close to a macro-inclusion during single pass reductions in the hot rolling of steel slabs: A numerical study. Journal of Materials Processing Technology. 2005. Vol. 170, iss. 1–2. pp. 142–150.
6. Dyi-Cheng Chen. An investigation into the shape rolling of sectioned sheets with internal voids using the finite element method. Procedia Engineering. 2014. Vol. 79. pp. 173–178.
7. Chia H., Patel G. Characterization of rod and wire defects produced during the manufacturing of copper. Wire Journal International. 1996. June. pp. 50–59.
8. Magalhães F. C., Pertence A. E. M., Campos H. B., Aguilar M. T. P., Cetlin P. R. Defects in axisymmetrically drawn bars caused by longitudinal superficial imperfections in the initial material. Journal of Materials Processing Technology. 2012. Vol. 212, iss. 1. pp. 237–248.
9. Zaheer T. Possible solutions to low twist quality in copper rod. Wire Industry (UK). 2000. August. pp. 542–545.
10. Khader I., Hashibon A., Albina J.-M., Kailer A. Wear and corrosion of silicon nitride rolling tools in copper rolling. Wear. 2011. Vol. 271, iss. 9–10. pp. 2531–2541.
11. Loginov Yu. N., Demakov S. L., Illarionov A. G., Ivanova M. A., Romanov V. A. Strukturnoe sostoyanie mednoy katanki, poluchennoy pri nepreryvnom protsesse litya-prokatki (Structural condition of copper wire rod, obtained during the continuous casting — rolling process). Tsvetnye Metally = Nonferrous metals. 2013. No. 8. pp. 87–92.
12. Prasad Y. V. R. K., Sasidhara S. Hot working guide: a compendium of processing maps. Ohio : ASM International, 1997. 545 p.
13. Loginov Yu. N., Zuev A. Yu., Inatovich Yu. V. Analiz sortovoy prokatki kislorodosoderzhashchey medi s uchetom nemonotonnosti kharakteristik uprochneniya (Analysis of oxygen containing copper rod rolling with the account of nonmonotonicity of hardening characteristics). Tsvetnye Metally = Non-ferrous metals. 2012. No. 7. pp 77–81.
14. Bayoumi L. S., Lee Y. Effect of interstand tension on roll load, torque and workpiece deformation in the rod rolling process. Journal of Materials Processing Technology. 2004. Vol. 145, iss. 1. pp. 7–13.