Characteristics of unsteady lubrication film in metal-forming process with dynamic roll gap
来源期刊：中南大学学报(英文版)2014年第10期
论文作者：WANG Qiao-yi(王桥医) ZHANG Ze(张泽) CHEN Hui-qin(陈慧勤) GUO Shan(过山) ZHAO Jing-wei(赵敬伟)
文章页码：3787 - 3792
Key words：metal-forming; interface; unsteady lubrication; dynamical roll gap; film characteristics
Abstract: Based on the theory of unsteady hydrodynamic lubrication and relevant mathematic and physical methods, a basic model was developed to analyze the unsteady lubrication film thickness, pressure stress and friction stress in the work zone in strip rolling. The distribution of pressure stress and friction stress in the work zone was obtained. A numerical simulation was made on a 1850 cold rolling mill. The influence of back tension stress and reduction on the distribution of pressure stress and friction stress between the roll gaps was qualitatively analyzed by numerical simulation. The calculated results indicate that the higher the back tension, the lower the pressure stress and the friction stress in the work zone, and the largest friction stresses are obtained at the inlet and outlet edges. The pressure and friction gradients are rather small at high back tension. The pressure-sensitive lubricant viscosity increases exponentially with the increase of pressure. The unsteady lubrication phenomenon in the roll bite is successfully demonstrated.
WANG Qiao-yi(王桥医)1, ZHANG Ze(张泽)1, CHEN Hui-qin(陈慧勤)1, GUO Shan(过山)1, ZHAO Jing-wei(赵敬伟)2
(1. School of Mechanical Engineering, Hangzhou Dianzi University, Hangzhou 310018, China;
2. School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, NSW 2522, Australia)
Abstract:Based on the theory of unsteady hydrodynamic lubrication and relevant mathematic and physical methods, a basic model was developed to analyze the unsteady lubrication film thickness, pressure stress and friction stress in the work zone in strip rolling. The distribution of pressure stress and friction stress in the work zone was obtained. A numerical simulation was made on a 1850 cold rolling mill. The influence of back tension stress and reduction on the distribution of pressure stress and friction stress between the roll gaps was qualitatively analyzed by numerical simulation. The calculated results indicate that the higher the back tension, the lower the pressure stress and the friction stress in the work zone, and the largest friction stresses are obtained at the inlet and outlet edges. The pressure and friction gradients are rather small at high back tension. The pressure-sensitive lubricant viscosity increases exponentially with the increase of pressure. The unsteady lubrication phenomenon in the roll bite is successfully demonstrated.
Key words:metal-forming; interface; unsteady lubrication; dynamical roll gap; film characteristics
