The effect of roll roughness and lubricant viscosity on the loads on the mill during cold rolling of steel strips

The tribological mechanisms of three commercially available oil-in-water emulsions were examined during cold rolling of low carbon steel strips. The independent variables in the study were the viscosity of the oil in the emulsions, the roll roughness, the roll velocity and the reduction. It was concluded that roll roughness plays an integral role affecting the dependent rolling parameters during cold rolling of steel strips. As expected, an increased roughness leads to an increase in the loads on the rolling mill. Within all experimental parameters good lubricating conditions were created. As long as any lubricant was present, the loads on the mill were reduced. The viscosity of the oil in the emulsion did not have a major effect on the loads. Increasing speeds caused a reduction of the loads at higher roll roughness but with the smoother rolls no speed effect was observed. At higher roll roughness almost hydrodynamic conditions were observed. The dynamic concentration theory appeared to fit the observations well.