Study Of Roller Vibration In Rolling Processes Of Cold Tandem Rolling

With the need for low-cost and high-quality produces increased, prevention of vibration becomes an increasingly important task in the design and operation of rolling mill in worldwide. This thesis intends to study the vibration phenomena in rolling mill due to the negative damping effect, the coupling effect in the immediate stands of rolling mill, the friction effect of the roll gap and the dynamic characteristic of bearing bracket. It also proposes the dynamic simulation approach which adapted ADAMS to simulate, and advances some corresponding approaches of restraining rolling vibration.Firstly, based on the theoretical analysis of the vibration reason in rolling mill, a theoretical model of the vibration system in rolling mill is build in this paper, and summarizes the main reason of vibration in rolling mills that is the strip entranced tension fluctuating causes the change of draught pressure, which causes the negative damping effect, the vibration system of the rolling mills loses its stability, and produces self-oscillation.Secondly, a frictional vibration model in the rolling mill is build on the basis of the study of frictional mechanism in the roll gap, announces that the change of frictional force causes draught pressure fluctuating, and cutting down the stability in rolling mill to produce self-oscillation.Thirdly, the coupling effect in the immediate stands of rolling mill is proposed, owing to continuous rolling characteristic of strip steel. By the dynamic simulation of ADAMS it is proved that the coupling effect quickens losing the stability of vibration system of the rolling mill, and increases the vibration magnitude.Fourthly, the gap between the bearing bracket and the stands causes impact to vibrate, and the dynamic simulation of ADAMS proves that the fluctuation energy of the system gets larger and the system gets more unstable, and causes the difference of strip steel.Finally, some corresponding approaches to restraining rolling vibration is proposed, for example, the vibration reason can be eliminated through cutting down the viscidity of emulsion, cutting down the strip entrance tension, increasing the roughness of surface of the roller etc., the vibration magnitude also can be reduced...