Limitation of dynamic loads of roll steel cells electromechanical systems by means of roll adjustment

The paper discusses the expansion of the rolling mills gauge due to the flat products production from hard-to-form steels. The research substantiates the relevance of the development of methods used to reduce the dynamic loads of thick plate mill reversible stands electromechanical systems occurring when the rollers grip metal. As it is shown, the control system of the horizontal rolls electric drives of Mill 5000 used at PJSC “Magnitogorsk Iron and Steel Works” (PJSC “MMK”) features no technical solutions providing for a reduction in the dynamic moment and speed deviations under the impact load. The paper presents oscillograms illustrating the unsatisfactory nature of transients during the rolling of hard-formed steel sheets. Thus, a method for limiting the torque by increasing the spacing between the rollers prior to metal gripping followed by the rolls return to a set position is justified. The paper present s a control system scheme with the suggested solution in place. The structure of the mathematical model of a rolling stand mechatronic system is considered. The model includes models of the horizontal rollers electric drive and the pressure devices (PD) hydraulic drive interconnected through metal, while the mathematical dependences describing the transient processes of the hydraulic PD and the change in pressure and moment under deformation are given. The dynamic mode of the workpiece grip with simultaneous change of the gap at various rates of PD movement is performed. As a result, the implementation of the algorithm based on the suggested method in 5000 camp automated process control system is considered a viable method. The oscillograms obtained during the workpiece gripping under the existing and the developed control algorithms are presented. The improvement of the dynamic speed and torque indicators is confirmed. The feasibility of studies aiming at the efficiency evaluation of the developed method implementation in the stands electromechanical systems of broadband and long rolling mills is noted.