Models for predicting roll roughness progressive loss in cold rolling

Roll roughness retention is one of the critical aspects in cold rolling, since the early loss of roughness in roll surface is responsible of many well known technological problems. Unfortunately, there is a large variety of parameters that may influence such kind of tribosystems and the problem of identifying a reliable prediction model is rather difficult a task. The aim of the present work, developed as part of a larger European Project, namely, TOPROLLS, consists into attempting to achieve a roll roughness loss prediction method that could be suitably used in the plants of interest. The model is restricted to three elementary wear mechanisms: adhesion-abrasion, fatigue, oil trapping effect. The lost volume per unit distance is assumed to be proportional to the dissipated power, and the latter is assumed proportional to the plant rolling power. The wear rate is regarded as a time depending variable, since it depends on the effective contact surface. Fatigue has been taken into account as in a previous investigation. Finally, the influence of surface flattening on lubrication has been considered in order to justify the asymptotic trends of wear and friction evolution with respect to the cycle number. The predicted trends of roughness and friction coefficient are compared to those obtained experimentally in some pilot and factory plants.