MISiS National University of Science and Technology, Moscow, Russia:

A. V. Zinoviev, Professor at the Department of Metal Forming
A. N. Koshmin, Postgraduate Student at the Department of Metal Forming, e-mail: koshmin.an@misis.ru

Svelen LLC, Saint Petersburg, Russia:
A. Ya. Chasnikov, CEO Advisor 

This paper describes the results of an experimental study into the microstructural evolution and mechanical properties in the deformation zone during continuous extrusion of M1 copper. The samples included residues that came from an industrial 350 Conform machine after it had produced rectangular copper bus bars. An optical microscope and an HVS-100 microhardness tester were used for microstructural and mechanical properties characterization. Analysis of the metal flow in the deformation zone showed that the regularities of the metal flow and structural transformation are true for all the samples. When subjected to extrusion, an undeformed workpiece with the cast structure comprised of 800–1000 μm crystalline grains acquires a structure similar to recrystallized structure comprising 50–35 μm grains. Quantitative data were obtained that describe how the equipment configuration and process parameters influence the hardness of the final product. The samples that came from the 10·30 and 10·60 mm bus bars are characterized with almost the same hardness (~90 kgf/mm²) and similar hardness distribution patterns. At the same time, the samples made from the 10·80 and 10·100 mm templates produced different results. Thus, in the latter hardness tends to go down as a workpiece goes through the die.

1. Konstantinov I. L., Sidelnikov S. B. Basics of metal forming processes: Textbook. Krasnoyarsk : SFU, 2015. 488 p.
2. Green D. Continuous Extrusion-Forming of Wire Section. Journal of the Institute of Metals. 1972. Vol. 100. pp. 295–300.
3. GOST 434–78. Copper rectangular wire and bars for electrical use. Specifications. Introduced: 01.01.1979. Moscow : Izdatelstvo standartov, 1979. 18 p.
4. Gorokhov Yu. V., Solopko I. V., Suslov V. P., Krylov M. A. Ures of the plastic current of billet material in deformation area at “Conform” continuous extrusion. Tsvetnye Metally. 2010. No. 12. pp. 69–71.
5. Shimov G. V., Fominykh R. V., Efremova A. S., Kovin D. S. Study of flow trajectories of continuously cast copper during the Conform pressing. Tsvetnye Metally. 2018. No. 4. pp. 79–85.
6. Mochalin I. V., Gorokhov Yu. V., Belyaev S. V., Gubanov I. Yu. Copper busbars extrusion on “Conform” installation with prechamber. Tsvetnye Metally. 2016. No. 5. pp. 75–78.
7. Gorokhov Yu. V., Timofeev V. N., Gubanov I. Yu., Plotnikova T. A., Ivanov A. G. Upgrade of the “Conform” installation. Tsvetnye metally i mineraly 2017. Krasnoyarsk : Nauchno-innovatsionny tsentr, 2017. pp. 591–
596.
8. Gorokhov Yu. V., Timofeev V. N., Belyaev S. V., Avdulov A. A., Uskov I. V., Gubanov I. Yu., Avdulova Yu. S., Ivanov A. G. The extrusion assembly of the “Conform” installation for continuous extrusion of non-ferrous metals. Izvestiya vysshikh uchebnykh zavedeniy. Tsvetnaya metallurgiya. 2017. No. 4. pp. 69–75.
9. Song L., Yuan Y., Yin Zh. Microstructural Evolution in Cu – Mg Alloy Processed by Conform. International Journal of Nonferrous Metallurgy. 2013. Vol. 2. pp. 100–105.
10. Yuan Y., Zhou Li Zh., Xiao Zhu, Zhao Z., Ziqi Yang Z. Microstructure evolution and properties of Cu – Cr alloy during continuous extrusion process. Journal of Alloys and Compounds. 2017. Vol. 703. pp. 454–460.
11. Li B., Li Ch., Yao X., Song B. Effects of Continuous Extrusion on Microstructure Evolution and Property Characteristics of Brass Alloy. Advanced Materials Research. 2011. Vol. 189–193. pp. 2921–2924.
12. Li B., Wei Qi, Pei J.-Y., Zhao Y. Flow characteristics of brass rod during continuous extrusion. Procedia Engineering. 2014. Vol. 81. pp. 647–651.
13. Raykov Yu. N. Processing of copper: Leaner guide for universities. Moscow : Institut Tsvetmetobrabotki, 2006. 448 p.
14. Gorokhov Yu. V., Sherkunov V. G., Dovzhenko N. N. et al. Continuous extrusion of metals: Basics of process design. Monograph. Krasnoyarsk : SFU, 2013. 224 p.
15. Zinoviev A. V., Chasnikov A. Ya., Potapov P. V. Physical and mechanical properties and plastic deformation of copper and copper alloys. Moscow : IRIAS, 2009. 260 p.
16. GOST 21073.1–75. Non-ferrous metals. Determination of grain size by comparison with microstructure scale (with Revision No.1; IUS 3-84) Moscow : Izdatelstvo standartov, 1984. 6 p.