S. Saxena et al., ANALYSIS OF COLD STRIP ROLLING UNDER HYDRODYNAMIC LUBRICATION, Journal of materials processing technology, 58(2-3), 1996, pp. 256-266
A model is proposed for cold strip rolling under hydrodynamic lubricat
ion which combines the finite-element analysis of the strip with the r
efined analysis of the lubricant film. The viscosity of the lubricant
is assumed to depend on both the pressure and the strain rate, whilst
the strip is modelled as rigid-perfectly plastic material. The thickne
ss of the lubricant film is assumed to vary parabolically from inlet t
o exit. The effects of various process variables (the reduction, the r
oll-radius-to-strip-thickness ratio, the lubricant viscosity and the r
oll velocity) on the interfacial stresses, the roil force and torque a
nd the film thickness are studied. It is shown that the interfacial no
rmal stress remains generally uniform over the are of contact and in n
o case develops a 'friction-hill'. Ln the proposed model, the roll for
ce remains virtually unaffected by both the lubricant viscosity and th
e roll velocity and thus remains insensitive to lubrication. At high r
eduction or for a low value of the roll-radius-to-strip-thickness rati
o, the film thickness becomes very small, requiring the use of high-vi
scosity lubricant or a large roll speed to maintain hydrodynamic lubri
cation.