轧制界面非稳态润滑动力学特性研究

发布时间：2018-04-24 08:01

本文选题：冷轧 + 润滑　；参考：《北京科技大学》2015年博士论文

【摘要】：金属冷轧时为了达到减少摩擦磨损、降低能耗以及提高轧件表面质量等目的,通常在其过程中采用适当的润滑。随着工业技术的不断发展,各行各业对轧制板带的需求不断增大,质量要求也越来越高,而高效率和高精度的产品要求使得轧机的非稳态润滑问题更为突出,这种失稳现象不仅影响轧件的板厚精度和表面形貌,甚至可能导致断带或设备损伤,带来巨大的经济损失。轧制过程中轧件发生塑性变形的同时润滑液由轧辊与轧件携带不断从辊缝间流过,轧制过程是一个瞬态的不断变化的过程,任何细微的扰动都有可能使轧制润滑系统处于一种非稳定状态,特别是高速轧制状态下非稳态问题会增多,其宏观表现为轧机振动,而随着生产力及生产效率的提高,高速轧制将会成为一种趋势,因此有必要对轧制界面非稳态润滑特性进行理论研究。本文以轧制理论、流体力学理论及振动理论为基础,对冷轧过程中稳态轧制润滑界面及非稳态轧制润滑界面展开了一系列理论研究和数值分析,主要内容包括： 1)根据轧制润滑实际情况,建立了包括入口区在内的稳态轧制界面流体润滑、混合润滑模型,并对其在不同工况条件下进行数值计算仿真。 2)建立了考虑表面形貌因素影响的包括流体润滑、混合润滑状态在内的非稳态轧制界面润滑模型,通过理论推导引入新的扰动因素并进行相应的数值计算仿真。以稳态轧制界面润滑模型为基础,提出非稳态轧制界面评价体系,对非稳态条件下轧制压力、油膜厚度等特性参数波动进行分析与评价。 3)以二辊实验轧机为平台进行了铝合金板带材轧制润滑实验。将实验数据与理论分析值进行了对比验证,结果表明理论计算所得结果与实验结果之间趋势一致,数值上满足一定精度要求,从而验证了理论分析的正确性。 4)以非稳态轧制界面微观应力分布为基础,建立轧机垂直振动及扭转振动模型,对不同扰动因素、不同工况下轧机宏观振动进行仿真与分析。
[Abstract]:In order to reduce friction and wear, reduce energy consumption and improve the surface quality of workpiece, proper lubrication is usually used in cold rolling. With the continuous development of industrial technology, the demand for rolling plate and strip is increasing in various industries, and the quality requirement is becoming higher and higher. The unsteady lubrication problem of rolling mill is more prominent due to the high efficiency and high precision product requirements. This kind of instability not only affects the thickness accuracy and surface morphology of rolled pieces, but also may lead to strip breakage or equipment damage and bring huge economic losses. During the rolling process, the plastic deformation of the workpiece occurs and the lubricating fluid flows through the gap between the rolls by the roller and the workpiece, so the rolling process is a transient and changing process. Any slight disturbance may cause the rolling lubrication system to be in an unstable state, especially in the high speed rolling condition, the unsteady problems will increase, its macroscopic performance is the rolling mill vibration, and with the increase of productivity and production efficiency, High speed rolling will become a trend, so it is necessary to study the unsteady lubrication characteristics of rolling interface. Based on the rolling theory, fluid dynamics theory and vibration theory, a series of theoretical research and numerical analysis on the stable rolling lubrication interface and the unsteady rolling lubrication interface during cold rolling are carried out in this paper. The main contents are as follows: 1) according to the actual conditions of rolling lubrication, a steady state rolling interface lubrication and mixed lubrication model including inlet region is established, and the numerical simulation is carried out under different working conditions. 2) the unsteady rolling interface lubrication model including fluid lubrication and mixed lubrication is established considering the influence of surface topography factors. A new disturbance factor is introduced through theoretical derivation and the corresponding numerical simulation is carried out. Based on the model of stable rolling interface lubrication, an evaluation system of unsteady rolling interface is proposed. The fluctuation of rolling pressure and oil film thickness under unsteady condition is analyzed and evaluated. 3) the lubrication experiment of aluminum alloy sheet and strip was carried out on the platform of two-high experimental mill. The experimental data are compared with the theoretical analysis results, and the results show that the theoretical results are consistent with the experimental results, and the accuracy of the theoretical analysis is satisfied numerically, which verifies the correctness of the theoretical analysis. 4) based on the micro-stress distribution of unsteady rolling interface, the vertical and torsional vibration models of rolling mill are established, and the macroscopic vibration of rolling mill under different disturbance factors and different working conditions is simulated and analyzed.
【学位授予单位】：北京科技大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TG331

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