Abstract:The roller's torsional self-excited vibration caused by roller stick-slip, and its influence on strip surface quality have been studied. Based on analysis of roller working surface stickslip, roller rotation dynamics equations have been established. The nonlinear sliding-frictional resistance has been linearized, and dynamics equations have been solved according to the characteristics of stick and slip between roller and strip. The results show that: 1) with decreasing stick time t₁, torsional vibration wave pattern gradually transforms from serration into sinusoid, and frictional self-excited vibration can coverall frequency components which are lower than that of free vibration; 2) stick time t₁ is directly proportional to torque increment ΔM_R, and is inversely proportional to live shaft stiffness K and drive shaft rotational velocity ω; 3) when slip time t₂ is basically steady, the longer the stick time, the larger the energy that system absorbs and discharges. As the slip time is a constant, it easily arouses strip surface shear impact and surface streaks.

Key words: rolling mill; drive; self-excited vibration