A Friction Model for Cold Strip Rolling With Two-Wavelength Surface Roughness in the “Mixed” Lubrication Regime

Abstract

A two-dimensional friction model has been developed for cold metal rolling in the “mixed” lubrication regime. Roughness is modelled using superimposed short and long wavelength asperities with a lay orientated along the rolling direction. The hydrodynamic pressure in the lubricant is solved using Reynolds’ equation, coupled with the crushing process of the two-wavelength roughness. This allows for the solution of film thickness and contact area ratio and hence friction coefficient through the roll-bite. The model extends the authors’ earlier model [15] by allowing for a variation in hydrodynamic pressure across the width of the contact. Predictions for both the surface roughness and the friction coefficient are in reasonable agreement with published measurements.