ПІДВИЩЕННЯ ЕКСПЛУАТАЦІЙНОЇ НАДІЙНОСТІ ВУЗЛА РОБОЧОГО ВАЛКА З ВНУТРІШНІМ ДЖЕРЕЛОМ НАГРІВУ ШЛЯХОМ ПРОГНОЗУВАННЯ ЙОГО ТЕРМОНАПРУЖЕНОГО СТАНУ
DOI:
https://doi.org/10.32782/3041-2080/2025-3-21Keywords:
reliability, warm rolling, roll assembly, internal heating, thermal stress state, temperature field, mathematical modelAbstract
Rolling rolls are one of the decisive factors in the formation of flat-rolled product quality indicators. In order to be able to promptly assess the operational reliability of the roll to ensure stable quality indicators, a model of the temperature-stressed state of work rolls with an internal heating source was developed. Considering that during the hot rolling process, the rolls are characterized by high levels of deforming forces and the presence of elevated temperatures in the deformation zone, a complex stressed state arises in them, caused by the joint action of torques, residual stresses, contact forces, bending moments and thermal loads. Contact stresses exert the maximum impact on the stability of work rolls. The model is based on solving the differential equation of heat conductivity and uses elements of the theory of elasticity. The roll is considered a thick-walled pipe with a symmetric temperature distribution along the longitudinal axis, which is loaded by the full rolling force, the reaction from the support rolls and the temperature loads caused by the temperature mismatch of the inner and outer surfaces. The developed mathematical model solves the problem of determining the thermally stressed state of the working roll, which allows for predicting the operational reliability of the rolls during the rolling process. Thus, the result of the numerical implementation of the model showed that at a certain ratio of the outer and inner radii of the roll, the stresses at the upper point of the axial channel change from relatively safe compressive stresses to more dangerous tensile stresses. Also, the analysis of the results showed that an increase in the diameter of the inner hole leads to a relative decrease in the temperature stresses on the surface of the axial hole and a decrease in the temperature stresses on both the outer and inner surfaces of the working roll. In general, the developed mathematical model can be used both for optimizing the design parameters of the roller assembly and for predicting operational use reliability.
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