高速轧机工作界面非稳态混合润滑过程多因素耦合辊缝力学特性研究

综合运用摩擦润滑理论、流体力学理论、轧制理论,建立了考虑动态辊缝非稳态润滑过程多因素耦合轧制界面力学模型.该模型综合运用了基于非稳态润滑过程的界面摩擦模型、工作辊运动模型、辊缝应力分布模型构成的界面薄膜约束多因素耦合模型.系统分析了非稳态混合润滑状态下,当压下率和表面粗糙度为定值时不同时刻工作区压应力和摩擦应力的分布情况,以及压下率为定值时工作区压应力、摩擦应力随表面粗糙度和后张应力变化的情况.结果表明:在压下率和表面粗糙度为定值时,当具有较大的后张应力时,工作区压应力和摩擦应力却较低,同时压应力梯度和摩擦应力梯度也相当小,摩擦应力在入口和出口边缘处达到最大,当后张应力减小时,辊缝间压应力和摩擦应力增加,压应力梯度和摩擦应力梯度较大;在压下率为定值而表面粗糙度为变量时,当后张应力较大时,表面粗糙度对工作区中的压应力和摩擦应力影响非常大,辊缝间压应力和摩擦应力随着表面粗糙度的增加而增加,当后张应力较小时,表面粗糙度对工作区中的压应力和摩擦应力影响不太明显.

An Investigation into the Mechanical Properties of Multi-factor Coupling Roll Gap in the Unsteady Mixed Lubrication Process of High-speed Mill Work Interface

Friction lubrication theory, fluid mechanics theory and rolling theory were integrated to establish mechanical model considering multi-factor coupling rolling interface in unsteady lubrication process of dynamic roll gap. Interfacial films constraints were integrated to constitute multi-factor coupling model based on the unsteady lubrication process interface friction model, the work roller movement model and the roll gap stress distribution model. A systematic analysis of the corresponding distribution of the pressure stress and friction stress of work zone at different time was made when the reduction rate and the surface roughness value were fixed during unsteady lubrication. At a certain reduction the influence of surface roughness and back tension stress on the pressure stress and friction stress in the work zone was also analyzed. Results indicate that under the condition of larger back tension stress when the reduction rate and the surface roughness value were fixed the pressure stress and friction stress was low. The pressure stress gradient and friction stress gradient were quite small at the same time. The friction stress got the maximum in the edge of inlet and outlet, the pressure stress and friction stress of roll gap increased when the back tension stress decreased. The pressure stress gradient and friction stress gradient were larger when the reduction rate and the surface roughness value were variable. When the back tension stress was large, the influence of surface roughness on the pressure stress and friction stress in the work zone was very large, the pressure stress and friction stress of roll gap increased with the surface roughness, when the back tension stress was small, the influence of surface roughness on the pressure stress and friction stress in the work zone was obvious.