金属塑性加工工作界面非稳态润滑轧机振动控制

Control of mill vibration for unsteady lubrication based on metal-forming processes

针对轧机垂直系统经常发生的自激振动现象,综合运用轧制理论、流体力学理论、润滑摩擦理论以及机械振动理论,建立考虑辊缝非稳态润滑过程轧机系统振动模型。该模型综合运用工作界面上的轧制力模型、界面摩擦模型、工作辊运动模型构成的界面薄膜约束多重耦合模型,定量分析一些主要参数对轧机垂直自激振动临界速度和振幅的影响。研究结果表明:轧制润滑乳化液的黏度越大,振动的临界速度越低;轧件的出口厚度越小,入口厚度越大,振动临界速度越低;轧件的变形抗力越高,振动临界速度越低;轧辊、轧件的表面粗糙度越高,轧机振动临界速度越高;轧辊半径越大,振动临界速度越高;轧机垂直系统本身的正阻尼(工作辊间阻尼以及压下油缸阻尼)越大,振动临界速度越高,振幅也越小;轧制速度越高,振幅越大。

The self-excited vertical vibration of high speed rolling mill was chosen as the case for analysis.On the basis of rolling theory,hydromechanics theory,lubrication and friction theory,mechanic vibration theory,the vertical vibration model of rolling mill system based on the rolling gap at unsteady lubrication process was presented.In the analysis of vertical vibration process,the interface coupling model of thin film binding that consists of the rolling force model,interface friction model and work roll movement model was taken into account.The self-excited vertical vibration mechanism of work roll was analyzed,the negative damping character was discussed and vertical self-excited vibration of the work roll was explained.Using the simulation program,the effect of some main parameters on critical speed and amplitude for vertical vibration was analyzed quantitatively too.The results show that rolling lubricant viscosity,strip inlet thickness and strip deformation resistance are inversely proportional to the critical speed of vibration;strip outlet thickness,the roughness of roll and strip,roll radius and system positive damping are directly proportional to the critical speed of vibration;system positive damping is inversely proportional to the amplitude of vibration;and rolling speed is directly proportional to the amplitude of vibration.