Dynamics and stability analysis of rolling mill system during variable gauge rolling

This paper investigates the dynamic behavior of a rolling mill during variable gauge rolling. Considering that the variation of rolling process parameters and the movement of hydraulic cylinder are the remarkable features of the variable gauge rolling process, the dynamic rolling force model and the hydraulic cylinder dynamic model were established respectively, and the rolling mill dynamic model was established based on the structure-process coupling strategy. The Incremental Harmonic Balance Method (IHBM) is used to solve the amplitude–frequency characteristics of the rolling mill system, and the Runge–Kutta method is used to solve the vibration characteristics. The results indicate that as the piston of the hydraulic cylinder is displaced, the stiffness of hydraulic cylinder changes and exhibits nonlinear features. The nonlinear characteristics of the hydraulic cylinder affect the dynamic behavior of the rolling mill, which presents different dynamic behaviors when the piston is in different initial positions for variable gauge rolling. The results provide a theoretical reference for the analysis and control of rolling mill dynamic behavior during variable gauge rolling.