Surface quality of cold rolling aluminum strips under lubrication condition

The effects of oil film on the rolled surface, including surface roughness and topography, were investigated during cold rolling of aluminum strips. Various mineral oils with viscosities from 0.10 to 1.6 Pa.s were used to obtain different oil film thicknesses. Results from experiment and calculation show that the thicker oil film protects the initial roughening surface so that it leads to an increase in roughness of the rolled surface, in particular when the surface roughness has the character of direction. The rolled surface roughness was determined by λ, which is the ratio of oil film thickness to the combined surface roughness. When λ > 3, the rolled surface roughness increases rapidly with the increase in oil viscosity, whereas the surface roughening has already occurred when λ < 3, but the increase of the rolled surface roughness with increasing viscosity is not distinct.