Ural Federal University named after the first President of Russia B. N. Yeltsin, Ekaterinburg, Russia:
S. O. Nepryakhin, Cand. Eng., Associate Prof., Institute of New Materials and Technologies, e-mail: s.o.nepriakhin@urfu.ru
M. G. Martynov, Master Student

The purpose of the work is to identify possible ways to solve quality improvement issues, based on the analysis of the current calibration mode of round hot-rolled steel. Based on the dimensional analysis, it was found that the primary problem of the impossibility of obtaining the dimensions established by the regulatory documentation at the calibrated frame is the insufficient accuracy of the dimensions of the billets obtained at the linear hot rolling mill. To ensure the required accuracy, it was decided to analyze and change the geometry of the die channel. As a result of the analysis of the angle of inclination of the working cone, it was found that the angle of 11° is not optimal from the position of minimizing the drawing force during reduction from a diameter of 82 mm to 80 mm. It was decided to reduce the slope of the die to 6°, at which, according to calculations according to the Perlin formula, the drawing force is reduced to a value of 247 kN. In the next stage, based on practical recommendations, the length of the calibrating belt was increased from 4 m to 8 mm, which theoretically should allow for a more stable formation of the final size. To check the operability of the proposed solutions, modeling was carried out using the Deform 3D software complex. To debug the model, you selected values for the elastic properties of the workpiece material based on the current mode. Taking into account the selected properties, modeling of the deformation process with the new geometry of the die was carried out. The results of the simulation showed the possibility of obtaining calibrated rolling dimensions within the tolerance even from a hot-rolled workpiece, the size of which exceeds the upper tolerance field. The result of the work was the testing of the drawing mode with the new geometry of the die. At the moment, 286 tons have been drawing, while the tool consumption has decreased by 40 %.

1. Kalyakulin S. Yu., Mitin E. V., Orlova E. D., Mitina A. E. Characteristics of metallurgical production and technological processes as objects of control. XLVI Ogaryov Readings: Proceedings of the scientific conference: Part 1. Saransk: National Research Mordovia State University. 2018. pp. 398–403.
2. Gugis N. N. The main trends in the development of the production of rolled products, pipes and hardware in 2017–2019. Part 1. Production of flat and, long products and hardware. Chernye Metally. 2020. No. 1. pp. 23–27.
3. Zaides S. A. Manufacturing technology of stabilized calibrated steel. Stal. 2015. No. 12. pp. 50–53.
4. Korchunov A. G., Pivovarova K. G. Investigation of changes in steel surface roughness parameters during calibration. Modern achievements of university scientific schools: proceedings of the national scientific school-conference, Magnitogorsk, November 25–26, 2021. Magnitogorsk : Nosov MSTU, 2021. pp. 41–45.
5. Rodinkov S. V., Pavlenko V. V., Drozd V. G., Kriventsov A. M. Trends in the development of section mill stand design. Chernaya metallurgiya. Byulleten nauchno-tekhnicheskoy i ekonomicheskoy informatsii. 2015. No. 8 (1388). pp. 67–73.
6. Kriventsov A. M., Rodinkov S. V. Optimization of the ratio of radial and axial stiffness of section rolling stands in order to increase the geometric accuracy of section profiles. Tyazheloe mashinostroenie. 2013. No. 4–5. pp. 25–28.
7. Aryulin S. B., Oleinikov N. A., Yudushkin I. D. Standless non-stressed stands in section rolling production. Part 1. Zagotovitelnye proizvodstva v mashinostroenii. 2022. Vol. 20. No. 8. pp. 359–368.
8. GOST 7417–75. Calibrated round steel. Dimensions. Introduced: 01.01.1976.
9. GOST 2590–2016. Round hot-rolled steel bars. Dimensions. Introduced: 01.07.2009.
10. Zaides S. A., Nguyen V. Kh. Determination of residual stresses in calibrated bars. Izvestiya vuzov. Chernaya metallurgiya. 2017. Vol. 60. No. 2. pp. 109–115.
11. GOST 1050–2013. Metal products from nonalloyed structural quality and special steels. General specification. Introduced: 01. 01. 2015
12. Massé T., Fourment L., Montmitonnet P. The optimal die semi-angle concept in wire drawing, examined using automatic optimization techniques. Int. J. Mater Form. 2013. Vol. 6. pp. 377–389.
13. Sas-Boca I. M., Tintelecan M., Pop M., Iluţiu-Varvara D.-A., Mihu A. M. The wire drawing process simulation and the optimization of geometry dies. Procedia Engineering. 2017. Vol. 181. pp. 187–192.
14. Tintelecan M., Sas-Boca I. M., Iluţiu-Varvara D.-A. The influence of the dies geometry on the drawing force for steel wires. Procedia Engineering. 2017. Vol. 181. pp. 193–199.
15. Xin Ying Liu, Shun Hu Zhang. The design of a drawing die based on the logistic function for the energy analysis of drawing force. Applied Mathematical Modelling. 2022. Vol. 109. pp. 833–847.
16. Perlin I. L., Ermanok M. Z. Drawing theory. Moscow : Metallurgiya, 1971. 448 p.
17. Kokovikhin Yu. I. Technology of steel wire production. Kiev : Institute for system analysis in education, 1995. 608 p.
18. Smetneva N. Yu., Kharitonov V. A. Analysis of the influence of technological parameters on energy consumption when drawing and methods for their determination in production conditions. Obrabotka sploshnykh i sloistykh materialov. 2018. No. 1. pp. 8–20.
19. Rudskoy A. I., Lunev V. A., Shaboldo O. P. Drawing. Saint-Petersburg : Izdatelstvo Politekhnicheskogo universiteta, 2011. 126 p.
20. Gubkin S. I. Plastic deformation of metals. Vol. 3. Moscow : Metallurgizdat, 1960. 306 p.
21. Kolmogorov G. L., Chernova T. V., Averyanova E. M., Snigireva M. V. Optimal geometry of the technological drawing tool. Izvestiya vuzov. Chernaya metallurgiya. 2013. No. 7. pp. 51–53.
22. Tarnavskiy A. L. Efficiency of drawing with countertension. Moscow : Metallurgizdat, 1959. 152 p.
23. Dolzhanskiy A. M. Determination of traction stress and optimal die angle taking into account the criterion of the deformation zone shape. Metallurgicheskaya i gornorudnaya promyshlennost. 2003. No. 4. pp. 61–63.
24. Guryanov G. N. The relationship between the angle of the die working cone and the drawing coefficient at the minimum force of drawing wire from different materials. Uprochnyayushchie tekhnologii i pokrytiya. 2019. Vol. 15. No. 7. pp. 291–303.
25. Shun Hu Zhang, Gang Liu, Dong Chen, Qing Yu Zhang et al. Plastic mechanical analysis of drawing force based on a twin elliptical die. Applied Mathematical Modelling. 2020. Vol. 77, Iss. 2. pp. 1446–1459.
26. GOST 3882–74. Sintered hard alloys. Types. Introduced: 01.01.1976.