OBRABOTKAMETALLOV Vol. 26 No. 4 2024 135 EQUIPMENT. INSTRUMENTS Investigation of the distribution of normal contact stresses in deformation zone during hot rolling of strips made of structural low-alloy steels to increase the resistance of working rolls Ivan Pospelov a,* Cherepovets State University, 5 Lunacharskogo pr., Cherepovets, 162600, Russian Federation a https://orcid.org/0009-0000-5974-5718, idpospelov@chsu.ru Obrabotka metallov - Metal Working and Material Science Journal homepage: http://journals.nstu.ru/obrabotka_metallov Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science. 2024 vol. 26 no. 4 pp. 125–137 ISSN: 1994-6309 (print) / 2541-819X (online) DOI: 10.17212/1994-6309-2024-26.4-125-137 ART I CLE I NFO Article history: Received: 23 August 2024 Revised: 16 September 2024 Accepted: 02 October 2024 Available online: 15 December 2024 Keywords: Normal contact stresses Structural low-alloy steels Deformation zone Elastic modulus of the strip Contact strength of working rolls Acknowledgements Some of the research was carried out in the operating conditions of PJSC Severstal. ABSTRACT Introduction. During the operation of the working rolls of the fi nishing groups of continuous wide-strip hot rolling mills, normal contact stresses have a decisive infl uence on its resistance and strength, especially when rolling a range of low-alloy structural steels with a minimum thickness range of 5.5–2.0 mm, which does not correspond to the passport characteristics of such mills. The subject of the study. Previously performed studies of the stress-strain state of the rolled strip in the deformation zones make it possible to estimate the level of normal contact stresses acting on the working rolls during hot rolling of strips of low-carbon steels. The paper discusses the results of the study of the stressed state of strips of low-alloy structural steels in contact with rolls, taking into account the features of the chemical composition of the metal and changes in its elastic properties during deformation at hot rolling temperatures. The results obtained are applicable to the evaluation of the contact strength of the fi nishing rolls of the rolling mill. The purpose of the work is to investigate the distribution of normal contact stresses in the deformation zones during hot rolling of strips of low-alloy structural steels to ensure high resistance of the working rolls. Material and methods. The study is based on the elastic-plastic model and equations for calculating normal contact stresses for each section of the deformation zone. The specifi city of variation of Young’s modulus (modulus of elasticity) of low-alloyed structural steels in accordance with certain hot rolling temperatures is studied in detail, and the contact strength of high-chromium cast iron work rolls is evaluated. Results and discussion. A reliable regression equation is obtained for determining the values of the Young’s modulus of the rolled strip as a function of changing hot rolling temperatures. The results of a numerical experiment are presented in the form of calculating the maximum normal contact stresses using the elastic-plastic model of the deformation zone and assessing the contact strength of the work rolls based on actual rolling conditions on an operating mill. New improved technological modes of hot rolling of low-alloy structural steels (0.1 C-Cr-Si-Ni-Cu, 0.18 C-Cr-Mn-Ti and 0.14 C-2 Mn-N-V) are proposed, which make it possible to reduce the maximum contact stresses and increase the resistance of the working rolls. For citation: Pospelov I.D. Investigation of the distribution of normal contact stresses in deformation zone during hot rolling of strips made of structural low-alloy steels to increase the resistance of working rolls. Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science, 2024, vol. 26, no. 4, pp. 125–137. DOI: 10.17212/1994-6309-2024-26.4-125-137. (In Russian). ______ * Corresponding author Pospelov Ivan D., Ph.D. (Engineering), Associate Professor Cherepovets State University, 5 Lunacharskogo pr., 162600, Cherepovets, Russian Federation Tel.: +7 963 353-53-71, e-mail: idpospelov@chsu.ru References 1. Gostev K.A. Optimizatsiya prokatnykh valkov v tselyakh snizheniya sovokupnoi stoimosti vladeniya [Optimization of rolling rolls with the purpose of reducing the TCO]. Stal’ = Steel in Translation, 2021, no. 10, pp. 19–24. (In Russian). 2. Hu K., Zhu F., Chen J., Noda N.-A., Han W., Sano Y. Simulation of thermal stress and fatigue life prediction of high speed steel work roll during hot rolling considering the initial residual stress. Metals, 2019, vol. 9 (9), p. 966. DOI: 10.3390/met9090966.
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