In order to create the ultra-fine grained steels, the hot rolling with a high reduction and a high rolling force is necessary, so that the tribological problems such as the improvement of the decrease of the rolling force, the prevention of the friction pick up and so on must be solved. One attempt for the solution of problems is to develop innovative hot rolling oils. Consequently, in order to understand the lubrication mechanism in hot rolling, it is desired that the data of the coefficient of friction under the wide range of tribological conditions are obtained. In this paper, the simulation testing machine in the laboratory for hot rolling is developed and the coefficients of friction are measured. The lubrication mechanism in hot rolling is investigated.
