Research On Coupled Vibration Of Rolling Mill

With the development of modern economy, the demand for plate strip increasescontinuously and the surface quality and dimensional accuracy of the plate strip arealso more and more important. With raising the speed of the rolling mill production,rolling mill vibration phenomenon happens occasionally. The vibration of the rollingmill is the main cause for the rolled steel’s surface quality faults with much severersituations that it may threaten the equipment safety and lead to accidents. More andmore people pay attention to the rolling mill vibration phenomenon.Rolling mill vibration is not only related to the main drive system and its ownnatural characteristics, but also has close connection with diverse pumping signals,such as the rolled products’ dimension variation, AGC pot modulation signal, rollereccentricity, the tension variation between front and back. Meanwhile, there are somecomplex vibration mechanism such as torsional vibration of the main drive system,vibration in the vertical direction and vibration in the horizontal direction. Aiming atthe vibration mechanism analysis, the article mainly studied as follows:1. In accordance with the main drive system’s practical structural parameters ofthe rolling mill, the collection quality method was adopted to simplify the main drivesystem and to calculate moments of inertia and torsional rigidities of variouscomponents. The main system dynamic model was set up to calculate the equivalentmoments of inertia and torsional rigidities. After vibration characteristics analysis, thenatural frequency and the main vibration mode of the rolling mill were calculated.2. According to the vertical system’s practical structural parameters of the rollingmill, the analytical calculation and finite element calculation were combined to solvethe equivalent masses and stiffness of the rolling mill frame, the AGC pot, the top andbottom back-up rollers, bearings and its bearing houses, the top and bottom workingrollers, its bearings and bearing houses and the bottom working roller base. The naturalfrequency and the main vibration mode of the vertical system were calculated.3. The horizontal vibration dynamic model of the rolling mill was built in whichthe installation eccentricity and the elastic deformation between the working roller andthe back-up roller were fully considered. The contact stiffness between the two rollerswas calculated and dynamic equations were established. The horizontal vibration wassimulated and calculated by finite element software. 4. On the basis of Chapter2,3,4, the Uermxo Equation and the elastic-plastictheory were involved to deeply study the deformation process of rolled products. Thestress compatibility equations in the direction of thickness and length were establishedto fulfill the coupling of three sub-systems. The rolling mill coupling model with17degrees of freedom was set up and different rolling mill parameters, rolling parametersand response situations of the rolling mill systems under different interference signalswere calculated through using MATLAB and C#.5. Taking1780four-roller hot rolling mill as example, the article conducted thesimulation analysis of the coupling model. The variation situation of rolled products’output thickness under different interference signals was obtained.The study achievement of the article is of great guiding meaning and hasimportant practical value to the rolling mill design.