Lubricant Capture During Hot Rolling of an Aluminum Alloy

Abstract

Commercially pure aluminum alloy strips were hot rolled at 300 °C to various reductions at various speeds. Four emulsions, containing oil droplets of different particle size distributions, were used as the lubricants. The roll force, the roll torque, the exit velocity, the forward slip and the reduction were monitored. The independent parameters were the roll speed, the reduction and the droplet size distribution of the emulsion with tight emulsions containing oil droplets of small diameters and loose emulsions containing large and widely varying oil droplet sizes. It was expected that the droplet size would be one of the most important parameters, affecting the loads on the mill. While some dependence of the rolling loads on oil droplet dimensions was noticed, it was not considered significant. The effect of speed during hot rolling with emulsions was different for the high and low-reduction rolling conditions, and with low reductions, it was different than observed using neat oils. The experimental results can be explained according to the initial plate-out and subsequent entrainment of the oil. While no special experiments were conducted to identify the existence of dynamic concentration mechanisms, it was assumed that at significantly higher rolling speeds this mechanism might prevail, making friction more strongly dependent on the emulsion droplet size distributions. As well, the data indicate that the emulsion droplet size effects could be more pronounced at higher rolling speeds.