Research On Vibration Energy Of Hot Tandem Mill Based On Power Flow

Rolling mill vibration is a worldwide problem,which limits the capacity release of rolling mill,becomes an obstacle to the production of thin and high value-added products,is a technical problem to be solved in the field of rolling at home and abroad,and has puzzled domestic and foreign scholars and field experts for a long time.The traditional methods based on force,vibration displacement,vibration velocity or vibration acceleration are often used to study the rolling mill dynamic model,rolling mill finite element model and rolling mill vibration on field.However,measuring the vibration response and vibration transmission of the structure with a single amount of force,displacement,speed or acceleration can not fully reflect the actual situation of vibration because vibration is transmitted in the form of energy.The vibration power flow can represent the force and speed of the system,and can reflect the absorption,transmission and consumption of the vibration energy of the system,which is an effective tool to study the vibration.Based on the measured vibration state of the continuous rolling mill,the power flow method is proposed to study the continuous rolling mill,as follows:The vibration power spectrum of rolling mill is obtained by combining the vibration speed and the rolling force in field.It is found that there is difference between the vibration energy and the vibration speed of each stand.Due to the consideration of rolling force,the vibration energy of FI and F2 rolling mills is relatively large.The power flow method is used to analyze the vibration of rolling mill,by comparing with the traditional methods we found that the power flow mode and harmonic response are quite different from the traditional vibration mode and harmonic response,and the former can better reflect the nature of vibration;in addition,the visualization of vibration power flow of rolling mill was studied by vectorization of harmonic response of vibration power flow and we found that there is a great difference between the vector distribution of vibration power flow and the traditional vector distribution of vibration displacement.The power flow in rolls is often larger,and the direction of power flow transmission is not single from bottom to top.The power flow mode of the interface between the rolling mill components is obtained.The influence of the mass,stiffness and damping of the components related to the interface on the power flow mode is discussed,and the results are consistent with the traditional vibration theory.The power flow harmonic response of the rolling mill interface is obtained by post-processing the finite element harmonic response data,and that of the input and output interface is proposed to characterize the vibration power transmissibility of the components,in addition,the influence of the stiffness change of the AGC cylinder on the vibration power transmissibility of the cylinder is studied.It is found that when the length of the cylinder is 50 mm,the conductivity of the oil cylinder is large,and it is easy to amplify the vibration of the input interface.In addition,the method of judging the vibration source by the conductivity is proposed.The vibration power is measured,and it is found that the rolling mill will produce severe vibration when the AGC system and strip co-exist.Considering the nonlinear characteristics of AGC cylinder,the dynamic model of the upper roll system of the rolling mill is established,and the response frequency characteristics of the model under multiple excitation frequencies are simulated and analyzed.It is found that the rolling mill will produce a lot of response frequencies.If the natural frequency of the mill is close to each other,severe vibration will be induced.Based on this principle,a vibration suppressor is proposed to change the output frequency of the system by eliminating part of the excitation frequency components,and finally achieve the purpose of vibration suppression.