A study of friction during the lubricated cold rolling of an aluminum alloy

The roll separating force, roll torque and forward slip measurements during the cold rolling of a commercially pure aluminum alloy, with lubricants, are presented. Using lighter oil, boundary or mixed lubrication is produced. With higher viscosity oil, negative forward slip is observed, indicating the onset of hydrodynamic lubrication. A one-dimensional model, in which the friction hill is eliminated and which works in the boundary and mixed lubricating regimes, is then developed and used to infer the magnitudes of the coefficient of friction through an inverse technique by matching the measured and computed roll forces, roll torques and the forward slip. The coefficients of friction are found to increase with increasing reduction and decreasing rolling speeds. The results are discussed in terms of the adhesion theory of friction. (C) 1997 Elsevier Science S.A.