Volgograd State Technical University (Volgograd, Russia):

N. A. Zyuban, Dr. Eng., Prof., Head of the Dept “Technology of Materials”, e-mail: tecmat@vstu.ru
D. V. Rutskiy, Cand. Eng., Associate Prof.
S. B. Gamanyuk, Cand. Eng., Associate Prof.
M. V. Kirilichev, Post-Graduate

In the work of computer simulation of the solidification of the ingot, the geometry of a 5.9-ton reverse taper ingot with a small amount of the hot top used to produce round rolled metal was proposed. The selected geometry makes it possible to obtain a structure in the solidified metal with a favorable arrangement of physical and chemical inhomogeneities of the cast metal. Calculation of temperature fields, which showed that in the proposed ingot, 1 h 45 min after the start of solidification, the advancing crystallization front closes and a long "closed" zone of liquid metal is formed, the height of which is 37% of the ingot body height. The data presented are consistent with real shrinkage defects, the length of which was 36% of the ingot body height. Comparison of the calculation of the temperature distribution field with the determination of the parameters of the cast structure showed that in the upper part of the ingot the distances between the secondary axes of the dendrites are maximum, which is associated with improved thermal performance of the hot top, which reduces the intensity of solidification and creates favorable conditions for the segregation of impurities, (С, S, P) and the transfer of non-metallic inclusions from the top of the ingot to the hot top. The use of reverse taper ingot with a small amount of the hot top leads to a decrease in waste from the hot-top and to obtain high-quality round rolled metal.
The work has been executed with support of the Russian Foundation for Basic Research, project No. 18-08\00050.

1. Dyudkin D. А., Ksilenko V. V. Modern steel production technology. Moscow: Teplotekhnik, 2007. 528 p.
2. Safronov А. А., Tazetdinov V. I., Torokhov G. V. Mastering the production of continuously cast billets with a diameter of 550 mm from pipe steel grades at continuous caster No. 2 in the Zhelezny ozon 32 electric steel complex. Stal. 2013. No. 10. pp. 58–62.
3. Safronov А. А. et. al. Study of metal chemical heterogeneity of continuously cast billet with a diameter of 460 and 550 mm of the Zhelezny ozon 32 electric steel complex. Stal. 2013. No. 8. pp. 18–22.
4. Bloom casters. Continuous Casting Machine Solutions: Fastest, Largest, Best in Quality. Available at: https://www.danieli.com/en/products/products-processes-and-technologies/bloomcasters_26_88.htm (accessed: 05.04.2019)
5. Safronov А. А., Prilukov S. B., Gasilov А. Yu. The quality of the macrostructure of a continuously cast billet and its regulation. Stal. 2013. No. 11. pp. 27–31.
6. Dyudkin D. А., Ksilenko V. V., Smirnov А. N. Steel production. Vol. 4: Continuous casting of metal. Moscow: Teplotekhnik, 2009. 528 p.
7. Kittaka S., Kaniki T., Watanabe K., Miura Y. Multi-Mode EMS for Slab Casters – Recent Improvements and New Applications. Nippon Steel Technical Report. 2002. No. 86. pp. 68–73.
8. Kubota J., Kubo N., Ishii T. Steel flow control with travelling magnetic field for slab continuous caster mold. Tetsu-to Hagane. 2000. Vol. 86, No. 4. pp. 271–277.
9. Nosochenko О. V., Isaev О. B., Lepikhov А. S., Dektyarev P. А. et. al. Reduction of the axial segregation of elements in a continuously cast billet with the introduction of steel tape. Stal. 2003. No. 9. pp. 42–44.
10. Belyi А. P. Central segregation heterogeneity in continuously cast slabs and thick plates. Moscow: Metallurgizdat, 2005. 136 p.
11. Thome R., Doppler K. G., Bleymehl М., Zimmer М. Elevation of qualitative parameters of rolled sections used in automotive industry based on soft reduction technology during continuous casting. Chernye Metally. 2018. No. 8. pp. 29–34.
12. Li J. Z., Jiang M., He X. F. et al Investigation on nonmetallic inclusions in ultra-low oxygen special steels. MMTB. 2016. Vol. 47. pp. 2386–2399.
13. Grigorovich K. V., Garber А. К. Analysis of carbon steels secondary treatment processes. Perspektivnye materialy. 2011. No. 13. pp. 13–25.
14. Dub V. S., Safronov А. А., Movchan М. А. et. al. Effect of the secondary treatment technology on types of formed non-metallic inclusions and corrosion resistance of steel. Elektrometallurgiya. 2016. No. 5. pp. 3–15.
15. Kazakov А. А., Kovalev P. V., Ryaboshuk S. V. et. al. Control of nonmetallic inclusions formation during converter steel production. Chernye Metally. 2014. No. 4. pp. 43–48.
16. Morozova T. V. Impact of steel production technology on the structure homogeneity and contamination by non-metallic inclusions in order to improve reliability of main pipelines: Dissertation … of Candidate of Engineering Sciences. Moscow: TsNIITMASh, 2012. 154 p.
17. Zaytsev А. I., Knyazev А. V., Amenzhonov А. V. et. al. Effect of non-metallic inclusions and impurities on properties and quality characteristics of round rolled products from special alloyed steels. Metallurg. 2017. No. 8. pp. 69–74.
18. Rodionova I. G., Baklanova О. N., Amenzhonov А. V. et. al. Effect of non-metallic inclusions on the corrosion resistance of low-alloy carbon steels for oilfield pipelines. Stal. 2017. No. 10. pp. 41–48.
19. Dub V. S., Romashkin А. N., Malginov А. N. et. al. Development of steel ingot casting technology. Chernye Metally. 2015. No. 8. pp. 6–19.
20. Romashkin А. N., Dub V. S., Tolstykh D. S. et. al. The criterion for assessing the tendency of steel to segregation in forging ingots. Metallurg. 2017. No. 10. pp. 35–40.
21. Dub V. S., Romashkin А. N., Malginov А. N. Analysis of kinetics of solidification of steel ingots of various configurations. Part I. Results of cold modeling. Metallurg. 2015. No. 11. pp. 47–56.
22. Dub V. S., Romashkin А. N., Malginov А. N. Analysis of kinetics of solidification of steel ingots of various configurations. Part I. Results of cold modeling. Metallurg. 2015. No. 12. pp. 20–26.
23. Mozgovoy А. V., Zhulyev S. I., Zyuban N. А. et. al. Study and optimization of ingot parameters for large-sized rolled products. Metallurg. 2008. No. 8. pp. 33–37.
24. Rutskiy D. V., Zyuban N. А., Gamanyuk S. B. et. al. Determination of ingots geometry with minimal defects in the axial zone and their application to obtain bars with a diameter of more than 300 mm. Metallurg. 2018. No. 11. pp. 33–39.
25. Zhulyev S. I., Zyuban N. А., Rutskiy D. V. Steel bars, quality issues and new technologies: monograph. Volgograd: VolgGTU, 2016. 179 p.
26. Zyuban N. A., Rutskiy D. V. Improvement of the casting technology for large ingots for rise of reliability and operating durability of turbine set rotors manufactured of these ingots. Chernye Metally. 2018. No. 2. pp. 32–38.
27. Kazakov А. А., Zhitenev А. I., Kolpishon E. Yu., Salynova M. A. Nonmetallic inclusions quantitative assessment for forgings made from super large steel ingots. Chernye Metally. 2018. No. 12. pp. 50–57.
28. Mozgovoy A. V., Zyuban N. A., Rutskiy D. V., Fedorov D. N., Knokhin V. G. Steel ingot mold. Patent RF, No. 84759. Published: 20.07.2009, Bulletin No. 20.
29. Rutskiy D. V., Zyuban N. A., Chubukov M. Yu. et. al. Study of features of solidification of ingots with various geometry and top part insulation based on mathematical modeling. Izvestiya VolgGTU. Seriya Problemy materialovedeniya, svarki i prochnosti v mashinostroenii. 2017. No. 6 (201). pp. 138–145.
30. Zhulyev S. I., Fomenko A. P., Rutskiy D. V., Fedorov D. N. Steel ingot casting apparatus. Patent RF No. 2285579. Applied: 28.02.2005. Published: 10.08.2006. Bulletin No. 22.
31. Bagmutov V. P., Zakharov I. N., Zyuban N. A., Rutskiy D. V. Crystal computer modeling system. Certificate of state registration of computer program. No. 2013613206 dated of 28.03.2013. VolgGTU, 2013.
32. Mozgovoy А. V. Optimization of steel ingot parameters with improved characteristics of the axial zone for large diameter steel bars: Dissertation … of Candidate of Engineering Sciences. Moscow: TsNIIChERMET, 2009. 134 p.
33. Buzinov E. I., Rutskiy D. V., Mozgovoy A. V., Zyuban N. A., Shelukhina Yu. M. Metallographic program. Certificate of state registration of computer program RF. No. 2010614950 dated of 29 July 2010. GOU VPO VolgGTU. 2010.
34. GOST 1778–70. Steel. Metallographic methods for the determination of nonmetallic inclusions. Introduced: 01.01.1972.
35. Khvorinov N. I. Crystallization and heterogeneity of steel. Moscow: Mashgiz, 1958. 392 p.
36. Merton C. Flemings. Solidification Processing, McGraw-Hill Book Company, New York, NY, 1974. 420 p.
37. Merton C. Flemings. Behavior of metal alloys in the semisolid state. Metallurgical Transaction: A. 1991. Vol. 22, Iss. 5. pp. 957–981.
38. Zhulyev S. I., Zyuban N. A. Production and quality issues of a forging ingot: monograph. Volgograd: VolgGTU, 2003. 168 p.
39. Rutskiy D. V., Zyuban N. A., Gamanyuk S. B. Study of the Hot Top Performance with Various Heat Insulators. Solid State Phenomena. 2018. Vol. 265. Materials Engineering and Technologies for Production and Processing III. pp. 1099–1103.
40. Fomenko А. P. Development and study of the ingot with a low top part and straight taper of walls for production of bars: Dissertation … of Candidate of Engineering Sciences. Moscow: TsNIIChERMET, 2007. 143 p.