Study On Frictional Self-Excited Vibration In Slip Zone Of Strip Rolling

Rolling mill vibration causes bright and dark stripes and uneven thickness on the surface of the rolled piece.This will not only reduce the surface quality of the rolled piece,but also affect the normal operation of the rolling equipment,and even seriously damage the rolling equipment and cause major production accidents.Aiming at the phenomenon of rolling mill self-excited vibration,this paper takes the second stand of a 1580 indeterminate four-high strip hot strip mill in a steel mill as the research object,analyzes and reveals its self-excited vibration mechanism.Firstly,based on the ABAQUS software,an explicit dynamics model of the F2 rolling mill is established to simulate the speed field of the rolling material in the rolling deformation zone,compare the given rolling speed,and determine the length of the front slip zone,the back slip zone and the adhesion zone.Solving parameters such as rolling quality and friction provide a basis for calculation.Secondly,establish the mechanical model of the rolling material in the front slip zone and the back slip zone under the conditions of high reduction rate rolling and vibration equations along the rolling direction in parallel,solve the critical speed of rolling vibration,compare the rolling speed and combine The conditions for the self-excited vibration of the system prove that the rolling piece in the sliding zone can produce self-excited vibration;MATLAB programming is used to solve the dimensionless displacement map and the phase diagram based on the chase phenomenon.The analysis result shows that the rolling piece in the sliding zone has negative damping self-excited vibration.Excited vibration,so that the entire rolling mill system generates self-excited vibration.This reveals the mechanism of rolling mill self-excited vibration.Finally,Based on ABAQUS modal analysis,the first 10 natural frequencies and main vibration modes of the rolling mill are obtained;The frequency simulation results show that the fourth frequency is roughly consistent with the theoretical calculations and the experimentally measured frequencies when the rolling mill vibrates strongly.the main vibration of the rolling mill at this time is mainly manifested as vertical vibration.Based on numerical analysis,simulation analysis and experimental test comparison,the horizontal self-excited vibration mechanism of rolling pieces in the front slip zone and the back slip zone has important theoretical significance and engineering application value in suppressing the rolling mill self-excited vibration.