Research on Contact Behavior of Single Asperity on Work Roll Surface in Mixed Lubrication

Abstract

The present paper focuses on asperity contact during cold rolling at a microscopic level. As analyses of such a contact are not practical with experimental facilities, a three-dimensional finite element method (FEM) is adopted to simulate the indentation and furrow behaviors of a single asperity on work roll surface in mixed lubrication. The effects of the tensile stress, the hydrodynamic pressure and the plastic deformation of steel strip are considered comprehensively. Most calculations are done for parabolic asperities, but for comparison purposes, some results are presented for sinusoidal and elliptical asperities. The indentation behaviors including uplift height of edges and plastic deformations of strip steel are calculated and analyzed. The friction during furrow behaviors is also considered. It reveals that the reduction and lubrication condition has a significant effect on the uplift height of strip steel edges around the asperity. Furthermore, long-term repeated effects of mixed lubrication contact are liable to spark asperity wear and decrease the roughness of rolls and even cause the failure of rolls in strip rolling mills.