Implementation of calculation methods in a specialized computer system of the stress-deformation and temperature state of steel bar coils
Authors:   Physico-technological Institute of Metals and Alloys of the NAS of Ukraine, Mazur V. L. , Tymoshenko V. I. ,   Institute of Technical Mechanics of the NAS of Ukraine and the State Space Agency of Ukraine, Prykhodko I. Yu. ,   Iron and Steel Institute of Z. I. Nekrasov National Academy of Sciences of Ukraine
Published: May 2023

The theory of formation and transformation of the stress-deformation and temperature state of rolls of hot-rolled and cold-rolled steel bars during their winding-unwinding in the processes of rolling, heat treatment, training, transportation, storage, and performance of other production operations at metallurgical plants has been developed. Mathematical models, algorithms and a computer system implementing them are proposed. A description of the possibilities of using this system when solving various tasks is given. In the computer system, an approach to assessing the influence of the parameters of the process of cold rolling and winding the stock into rolls, the temperature and speed regimes of their heating and cooling during annealing in hood furnaces is considered. For the first time, the methodology for identifying patterns of influence of inter-turn gaps in rolls on their stress-strain state was disclosed. The procedure for detecting the effects of cold rolling speed, temperature, tension of the rods rolled and wound into rolls, and their surface roughness on the stress-strain state of the rolls is shown. In detail, the implementation of new ideologies and approaches to solving the problem of determining the stress-strain state (STS) of rolls is shown in the computer system. Models and algorithms for calculating VAT, which are the basis of the computer system, are developed on the basis of classic solutions in the field of materials science, theories of elasticity, metal pressure treatment, heat engineering, gas dynamics, numerical methods and other fields of knowledge. The computer system revealed the mechanisms of forming the temperature and stress-strain state of rolls of steel bars in the processes of rolling, heating, isothermal aging and cooling during annealing in hood furnaces; the influence of the temperature and speed regimes of rolling and annealing on the occurrence of critical inter-turn pressures in the rolls, which lead to surface defects of the "bend line" (breaks) and defects in the shape of the rolls, is taken into account. The possibilities of influencing the VAT of rolls during rolling by adjusting the tension of the staffs, and during annealing by adjusting the duration of isothermal exposure and the rate of subsequent cooling of the rolls, are revealed. References to literary sources are provided, which detail the results of research on scientific and technical problems implemented in the computer system. In the computer system, methods of winding cold-rolled bars into rolls are used, which exclude the loss of their stability and the formation of "bends", subsidence, "bird" defects during the production of thin sheet steel in industrial conditions. Recommendations are given regarding the choice of a rational technology for the roll production of hot-rolled and cold-rolled sheet metal. The developed solutions are implemented in the "CoilTemper3D" computer system and are used in production.