Reappraisal of hydrodynamic lubrication in metal rolling process

Abstract

In the present paper a theoretical and experimental study of the lubrication behaviour in the metal rolling process has been conducted. In the theoretical analysis, which takes account of the variation of lubricant viscosity with pressure and temperature and plastic deformation of the strip, the effect of the Newtonian as well as non-Newtonian behaviour of the lubricant on the lubrication performance has been considered. The generation of heat within the lubricant is considered and adiabatic conditions have been adopted in the thermal analysis. Results of the theoretical analysis showed that dilatent lubricants ( n>I ) cause higher hydrodynamic pressure, lower film thickness, and higher reduction ratios. Meanwhile, the heat generated in the oil film leads to lower pressure, film thickness, and reduction ratios. A laboratory scale rolling mill has been constructed to asses the effect of lubricant viscosity and rolling speed on the oil film thickness, hydrodynamic pressure, and temperature distribution in the oil film for possible comparison with the theory.