Measurements of Surface Roughness in Cold Metal Rolling in the Mixed Lubrication Regime

M. P. F. Sutcliffe, H. R. Le
2000 Tribology Transactions  
This paper describes measurements of the change in surface roughness of aluminiur~i strip due to cold rolling. Rolling is in the mixed lubrication regime, where there is both asperity contact and hydrodynamic action. The strip is in the as-received condition before rolling, with a continuous spectrum of roughness wavelengths. The spectra of roug/~rless for both the initial and rolled sugaces are used to extract amplitudes for long and short wavelength componerrts, with an arbitrary division at
more » ... itrary division at a wavelength of 14 ptn between these components. It is found that the short wavelength components persist more than the long wavelength components, and that flattening of the strip increases with reduction in strip thickness. The qualitative effect of wavelength on flattening is similar to that observed with unlubricated rolling (Sutcliffe, 1999) , and is in line with theoretical models of mixed lubrication. The effect of reduction is not predicted by existing theories, but is ill agreement with measured variations of friction with reduction. Final Manuscript approved April 6,1999 = fraction of nominal area in contact between roll and strip = theoretical film thickness in the bite for smooth rolls and strip = length of the bite = dimensionless speed parameter S = 2qo DRIYLo" = roll radius = mean entraining velocity = plane strain yield strength of the strip = pressure viscosity coefficient of lubricant = temperature viscosity coefficient of lubricant = viscosity of lubricant (at ambient pressure) = ratio of the theoretical smooth film thickness to the initial combined roughness
doi:10.1080/10402000008982310 fatcat:udpojeh4njhpfmpge6mbnf2hue