Experimental Measurements of Lubricant Film Thickness in Cold Strip Rolling

Abstract

This paper reports on experimental measurements of film thickness and area of contact ratio when cold rolling metal has been measured on an experimental mill. Where the film thickness is significantly greater than the roughness amplitude, measured film thicknesses are up to a factor of two less than the theory for smooth surfaces. That difference is attributed to the uneven lubrication conditions in the experiment. The small effect of this uneven lubrication on the theoretical film thickness is estimated where roughness is important. When this is taken into account, agreement between the film thickness measurements and a theory for lubrication in the mixed regime (see Sutcliffe and Johnson paper pp 249–261), is reasonable. The measured area of contact ratio is found to agree reasonably with the contact area ratio deduced from the measured film thickness and original roughness height distribution.