冷轧过程中的混合润滑特性

Mixed Lubrication Characteristics of Cold Rolling Process

基于Christensen的表面粗糙峰分布假设,以轧制理论、流体力学理论为基础建立了考虑表面粗糙度的冷轧混合润滑模型,并提出了混合润滑摩擦状态约束关系式用来判别摩擦状态.对不同条件下油膜厚度、接触面积比、压应力及摩擦应力分布情况进行了仿真分析.结果表明:随着压下率的增加,油膜变薄、界面接触面积比增加、应力增大;同时,表面粗糙度对界面接触面积比及应力分布有较大影响,粗糙度增加,界面接触面积比增加,压应力及摩擦应力均增加.较高的润滑液黏度或轧制速度可以有效地降低轧制界面摩擦力及轧制力.

Based on the surface asperity distribution hypothesis of Christensen and the theory of rolling and hydrodynamics,a mixed lubrication model was set up for cold rolling process in which surface roughness is taken into consideration.The mixed film lubrication constraint relation was also proposed to judge the friction condition.The distribution of film thickness,contact area ratio,pressure stress and friction stress were simulated and analyzed under different conditions using this model.The results showed that larger reduction results in a thinner film thickness,larger contact area ratio of the interface and higher stress.Surface roughness was shown to have a pronounced effect on the contact area ratio and the stress distribution.As the surface roughness increases,the contact area ratio,as well as pressure stress and friction stress,would increase.Higher viscosity lubricant or roll speed can reduce the friction and the rolling force effectively.