DOI: 10.18503/1995-2732-2021-19-3-102-108

**Abstract**

An important factor of a hot rolling process is a thermal state of steel in the mill line. The development of feasible temperature and speed schedules for heating slabs and producing strips requires a large number of experiments, time and costs. Therefore, to solve problems aimed at manufacturing finished products with a given set of properties, we need to apply a modern approach to carrying out research. One of these methods is a combined use of physical and mathematical modeling. This paper presents the results of experimental studies on a heating process of steel samples made from slabs of current production in order to specify thermophysical coefficients of steel grade 17GS. The samples were stepwise heated in a muffle furnace and soaked to achieve a uniform temperature over the sample volume; as a result, the authors obtained time-temperature curves. Physical modeling in DEFORM-3D was used to develop a mathematical model of heating steel, repeating laboratory research, in order to check adequacy of the model. Using the research results, the authors simulated the thermal state of steel in the hot rolling mill line. The simulation was carried out in two stages: the first one was heating a slab before hot rolling; the second one was hot rolling in roughing stands. The surface temperatures obtained during the simulation and compared with the readings of a pyrometer after the 5th stand showed a difference not exceeding 15ºС, which indicated adequacy of the model. The developed mathematical model is adequate and can be used to simulate the thermal state of steel during the formation of non-uniform properties of long products.

**Keywords**

Laboratory research, mathematic modeling, heating, rolling, thermal state, DEFORM-3D.

**For citation**

Levykina A.G., Gorbunov K.S., Pozdnyakova A.I., Solovyov V.N. Study on a Thermal State of Steel Using Methods of Physical and Mathematical Modeling. Vestnik Magnitogorskogo Gosudarstvennogo Tekhnicheskogo Universiteta im. G.I. Nosova [Vestnik of Nosov Magnitogorsk State Technical University]. 2021, vol. 19, no. 3, pp. 102–108. https://doi.org/10.18503/1995-2732-2021-19-3-102-108

1. Mukhin Yu.A., Solovyov V.N, Bobkov E.B. Effect of a deformation and speed schedule of hot rolling in roughing stands of hot strip mills on a structure of steel grade St3. Chernye metally [Ferrous Metals], 2018, no. 11 (1043), pp. 12–15. (In Russ.)

2. Dozhdikov V.I., Ganul A.O., Mordovkin D.S. Optimizing an operation of power and process facilities for heating steel before rolling. Stal [Steel], 2018, no. 2, pp. 69–71. (In Russ.)

3. Mukhin Yu.A., Belskiy S.M., Chuprov V.B., Bakhaev K.V., Stoyakin A.O. Features of a temperature field of steel strips during hot rolling. Izvestiya vuzov. Chernaya metallurgiya [Universities’ Proceedings. Ferrous Metallurgy], 2015, vol. 58, no. 6, pp. 417–421. (In Russ.)

4. Mazur V.L., Nogovitsyn A.V. Teoriya i tekhnologiya tonkolistovoy prokatki (chislennyi analiz i tekhnicheskie predlozheniya) [Theory and technology of thin sheet rolling (a numerical analysis and technical proposals). Dnepropetrovsk: RVA Dnipro-VAL, 2010, 493 p. (In Russ.)

5. Solovyov V.N., Bobkov E.B. A temperature schedule increasing performance of a hot strip mill, when producing low-carbon steels. Chernye metally [Ferrous Metals], 2020, no. 8, pp. 15–19. (In Russ.)

6. Levandovskiy S.A., Kinzin D.I., Sarancha S.Yu. On the issue of simulating metal forming processes: methods for optimizing software. Aktualnye problemy sovremennoy nauki, tekhniki i obrazovaniya: materialy 75-oy mezhdunarodnoy nauchno-tekhnicheskoy konferentsii [Current problems of modern science, equipment and education: proceedings of the 75th International Scientific and Technical Conference]. Volume 1. Magnitogorsk: NMSTU, 2017, pp. 76–79. (In Russ.)

7. Kalchenko A.A., Pashchenko K.G. Modelirovanie protsessov OMD s ispolzovaniem sovremennykh programmnykh produktov: uchebnoe posobie [Simulating metal forming processes using modern software: a tutorial]. Magnitogorsk, 2017. (In Russ.)

8. Bolobanova N.L., Garber E.A. Numerical modeling of a slab deformation process at various reduction values in vertical rolls of roughing stands on rolling mill 2000. Chernaya metallurgiya. Byulleten nauchno-tekhnicheskoy i ekonomicheskoy informatsii [Ferrous Metallurgy. Bulletin of Scientific, Technical and Economic Information], 2021, no. 77(6), pp. 675–681. (In Russ.)

9. Polyakov A.V., Shatshu Netshutzim R., Mazur I.P. Effect of process parameters of rolling in universal stands on shifting steel from edges to a longitudinal axis of workpieces. Report 1. Process parameters. Chernye metally [Ferrous Metals], 2020, no. 8, pp. 20–24. (In Russ.)

10. Polyakov A.V., Shatshu Netshutzim R., Mazur I.P. Effect of process parameters of rolling in universal stands on shifting steel from edges to a longitudinal axis of workpieces. Report 2. Critical point. Chernye metally [Ferrous Metals], 2020, no. 9, pp. 45–48. (In Russ.)

11. Klimes L., Stetina J., Parilak L., Bucek P. Study of thermal behavior of continuously cast billets. Engineering Mechanics, vol. 20, 2013, no. 3/4, pp. 237–246.

12. Markowski J., Knapinski M., Koczurkiewicz B., Fraczek T. The physical modelling of the process of normalizing rolling of S355J2G3 steel plates. The Metallurgist, 74 (6), 2007, pp. 296–300.

13. Konovalov Yu.V. Spravochnik prokatchika. V dvukh knigakh. Kniga 1. Proizvodstvo goryachekatanykh listov i polos [Reference book for rolling mill operators. In two books. Book 1. Hot rolled sheets and strips.]. Moscow: Teplotekhnik, 2008, 640 p. (In Russ.)

14. Levykina A.G., Chabonenko A.A., Shkatov V.V., Mazur I.P. The study of the thermal state of the metal in the production of the hot rolled strips in Deform 3D. Journal of Physics: Conference Series. 2018, no. 1134 (1), pp. 1–8. DOI: 10.1088/1742-6596/1134/1/012034

15. Mazur I., Levykina A., Laber K. The mathematical model of the thermal state of the metal in the hot rolling mill. The 19th International Scientific Conference “New Technologies and Achievements in Metallurgy, Material Engineering, Production Engineering and Physics”. A collective monograph edited by Marcin Knapiński. Czestochowa, Poland, EU. 2018. Series: Monografie, no. 78, pp. 168–173.