An optimal design approach for calibrated rolls with respect to fatigue life

In the hot rolling process calibrated rolls are used for the production of various simple and complex profiles. Main factors influencing the fatigue life of these rolls result from the technological process of the rolling; rolling temperature, rolling speed, roll groove design and turning due to wearing. In order to increase maximum fatigue life of the rolls, as well as to reduce overall energy consumption, increase production and reduce overall costs, an analysis of the influence of these parameters on roll fatigue life has been carried out. Based on this analysis, procedure of optimal design of calibrated rolls with respect to fatigue life is developed. The procedure involves both analytical and experimental methods to determine service loads; numerical analysis of local stresses by finite element method and determination of stress time history of individual local stress and stress spectrum from numerical analysis and pass schedule. The fatigue life estimation is carried out according to the fatigue life stress concept based on the local stress. This paper proves that with the application of this procedure, optimal relation between roll fatigue life and energy consumption can be achieved, as well as more optimal production and overall costs.