A THERMAL HYDRODYNAMIC LUBRICATION ANALYSIS FOR ENTRAINED FILM THICKNESS IN COLD STRIP ROLLING

A thermal hydrodynamic lubrication analysis which takes account of temperaturedependent viscosity variation along as well as across the film thickness is developed for the entrained film thickness in cold strip rolling using generalized Reynolds equation (Dowson, 1962). The results are compared with that of the two approximate models (i.e., the effective viscosity model and thermal Reynolds equation model) being widely used in metal forming lubrication literature. It is found that neither of the two approximate models is more accurate than the other and that neither can deal with the effect of surface temperature difference of the roll and strip adequately. © 1990 by ASME.