AbstractIn order to predict the performance of rolling oils in actual production mills, from tests in laboratory mills, the influence of various factors, such as shape factors work roll diameter (D), strip thickness (h1), operating conditions (reduction rate (r), peripheral velocity of roll (U0), strip velocity (U1)) and kinematic viscosity of the rolling oil (υ0) was investigated. A parameter RLI (Rolling Lubrication Index = u0(U0+U1)(1−r)(D/2h1.r)½) was found to be useful in predicting lubricating conditions in actual production mill applications.The coefficients of friction of mineral oils, some synthetic hydrocarbons including polybutene, and several kinds of additives were obtained from laboratory mills under the same condition of RLI value as that for finish rolling in actual production mills. With hydrocarbons, paraffins showed the lowest coefficient offriction, while aromatics exhibited a higher coefficient of friction, with naphthenes showing the highest.A high‐quality rolling oil was formulated using a combination of ester and paraffinic mineral oil. It is observed that this new oil can save 14% of energy consumed by a laboratory mill compared with conventional rolling oils. In production mills, nearly the same energy conservation level can be ach