Development of a Method for Determining the Coefficient of Friction in Cold Sheet Rolling

An experimental method for determining the friction coefficient in metal forming processes using a universal friction machine has been developed. This method allows one to compare the lubricating ability of different emulsions in an efficient way. The experiments were carried out on a MMW-1A universal friction machine. Samples of 0.09-mm cold-rolled strips (TS-435 steel, analog 08ps) and a sample of roll material of cold rolling mill of especially thin sheets, type RCM-1250 (60X2HFА steel) were selected for research. Besides optimization of the methodology of such experiments, the character of the influence of coolant pH on the friction coefficient was determined. Friction conditions–semi-liquid friction. The expediency of using annular samples of the pair with thickness S = 4 mm and more was confirmed. It has been found that the time of carrying out the experiment should be commensurable with the duration of the investigated process of metal pressure treatment. For cold thin sheet rolling, it is most appropriate to conduct a series of 4–5-s experiments. The processing of experimental data has shown that the increase in pH values of coolant leads to an increase in the friction coefficient. The results can be useful for calculation of energy and power parameters of cold rolling of strips, for calculation of rolling routes, and optimization of applied coolants in processes of cold deformation of metals.