OBRABOTKAMETALLOV MATERIAL SCIENCE Том 23 № 3 2021 EQUIPMEN . INSTRUM TS Vol. 6 No. 4 2024 3. A study is carried out of the distribution of normal contact stresses along the length of the deformation zone taking into account the specifi c features of the stress-strain state of the strip contacting with working rolls based on the existing hot rolling process mode in the most utilized stands of the fi nishing train of Mill 2000. According to the study results it is noted that the existing rolling process modes lead to growth of maximum contact stresses in the stand No.11 of the fi nishing train of the hot rolling Mill 2000 of PAO Severstal to dangerous range of values of 1,068–1,245 MPa in the plastic section of the deformation zone. The working rolls resistance to early emergency destruction under conditions of the above stated maximum stresses falling within and exceeding the range of permissible contact stresses [σ] = 1,050–1,200 MPa can be explained by the fact that the material of the working rolls in the contact area is in favourable conditions of all-round elastic compression. 4. Improved modes of reduction and specifi c interstand tensions, which can reduce and maintain maximum normal contact stresses in the stand No.11 of the fi nishing train in a safe range of 838–1,023 MPa, are calculated and suggested based on the previously developed principles of hot rolling process modes optimization to reduce fl uctuations in thickness and force. It is concluded that the developed approach to evaluation of lifetime of work rolls in hot rolling mill fi nishing trains when exposed to normal contact stresses and a new advanced method of the modes initial adjustment can be applied for designing the effi cient rolling technology for low-alloyed structural steels with the minimal thickness range of 5.5–2.0 mm. 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. 3. Weidlich F., Braga A.P.V., da Silva Lima L.G., Boccalini G., Souza R.M. The infl uence of rolling mill process parameters on roll thermal fatigue. International Journal of Advanced Manufacturing Technologies, 2019, vol. 102, pp. 2159–2171. DOI: 10.1007/s00170-019-03293-1. 4. Deng G.Y., Zhu Q., Tieu A.K., Zhu H.T., Reid M., Saleh A.A., Su L.H., Ta T.D., Zhang J., Lu C. Evolution of microstructure, temperature and stress in a high speed steel work roll during hot rolling experiment and modeling. Journal of Materials Processing Technology, 2017, vol. 240, pp. 200–208. DOI: 10.1016/j.jmatprotec.2016.09.025. 5. Kiss I., Pinca Bretotean С., Josan А. Experimental research upon the durability in exploitation of the Adamite type rolls. IOP Conference Series: Materials Science and Engineering, 2018, vol. 393 (1), p. 012090. DOI: 10.1088/1757-899X/393/1/012090. 6. Mercado-Solis R.D., Talamantes-Silva J., Beynon J.H., Hernandes-Rodrigues M.A.L. Modelling surface thermal damage to mill rolls. Wear, 2007, vol. 263 (17–20), pp. 1560–1567. DOI: 10.1016/j.wear.2006.12.062. 7. Kotrbacek P., Horsky J., Raudensky M., Pohanka M. Experimental study of heat transfer in hot rolling. Revue de Métallurgie, 2006, vol. 103 (7), pp. 333–341. DOI: 10.1051/metal:2006134. 8. Pinca-Bretotean C., JosanA., Kumar SharmaA. Infl uence of thermal stresses on the phenomenon of thermal fatigue of rolling cylinders. Journal of Physics: Conference Series, 2023, vol. 2540 (1), p. 012023. DOI: 10.1088/17426596/2540/1/012023. 9. Dünckelmeyer M., Krempaszky C., Werner E., Hein G., Schörkhuber K. Analytical modeling of thermo-mechanically induced residual stresses of work rolls during hot rolling. Steel Research International, 2010, vol. 81, pp. 86–89. 10. Garber E.A., Kozhevnikova I.A. Sopostavitel’nyi analiz napryazhenno-deformirovannogo sostoyaniya metalla i energosilovykh parametrov protsessov goryachei i kholodnoi prokatki tonkikh shirokikh polos [Comparative study of stress-strained state of metal and energy-force parameters of hot and cold rolling processes of thin wide strips]. Proizvodstvo prokata = Rolling, 2008, no. 1, pp. 10–15. 11. Garber E.A., Kozhevnikova I.A., Tarasov P.A. Eff ect of sliding and rolling friction on the energy-force parameters during hot rolling in four-high stands. Russian Metallurgy (Metally), 2007, vol. 2007, pp. 484–491. DOI: 10.1134/S0036029507060080.
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