Study On The Vibration Mechanism Of Four-roll Temper Mill And Chatter Marks On The Steel Strip Surface

In this paper,the vibration signals of roller system of four-roll cold rolling temper mill drived by a single-roll were analyzed.The stability and the negative damping characteristics of the contact interface of the work roll and the vibration mechanism of the system were also analyzed.Thus finding out the main reason of the vibration of strip surface in the process of temper mill.Through the analysis of the characteristics of the strip surface and the analysis of the stress state of the rolling deformation zone,it is found that there is a close relationship between the length of the contact arc length and the strip spacing of the strip surface,so that the factors affecting the strip surface chatter vibration frequency,and then find out the relevant measures to suppress the generation of vibration.The results of the study have the following conclusions:(1)During the use of the temper mill backup roll,the vibration energy of the system is gradually increased with the extension of the backup roll.The amplitude is obviously increased in the middle and late period of the backup roll,and the core vibration frequency is concentrated near 550 Hz.(2)In the initial stage,the main part of its vibration is the self-excited vibration which results from the negative damping characteristic of the contact surface of the work roll,which originates from the change of frictional direction by cross shear zone of asymmetrical rolling interface and the slipping of roll contact interface.In the middle and final stage,the forced vibration caused by the chatter marks accelerates the formation of the chatter marks,and the self-excited vibration of the system coexists with the forced vibration.(3)Rolling process parameters affect the chatter marks and vibration frequency of the strip's surface.Combined with the model to study the influence of rolling process parameters on the vibration frequency of the chatter marks on each steel surface.The results show that: for different steel grades,the vibration frequency of forced vibration is changed by changing the elongation,rolling speed,front and rear tension and friction coefficient of the rolling process parameters,so as to avoid the occurrence of resonance and reduce the possibility of strip surface vibration.