2009 Volume 50 Issue 576 Pages 54-58
To understand the behavior of oil in water (O/W) emulsion in the inlet zone of cold rolling under starved condition, Al-1050H-24 sheets were rolled with neat oil and O/W emulsion, while changing lubrication conditions. The thickness of the inlet oil film between the roll and the workpiece was measured, while changing base oil viscosity, particle size, O/W emulsion concentration and the type of emulsifier using the relationship between the calculated inlet oil film thickness with neat oil and the surface brightness of the sheet rolled with O/W emulsion. Trapping ratio was estimated from the measured inlet oil film thickness using the calculated system for inlet oil film thickness in O/W emulsion. It was found that the trapping ratio decreases with increasing droplet size and O/W emulsion concentration, so that inlet oil film thickness depends slightly on particle size and O/W emulsion concentration. On the other hand the effect of the type of emulsifier on trapping ratio was found to be significant, enabling us to increase inlet oil film thickness by selecting appropriate emulsifiers.
