Fatigue failure risk evaluation of bimetallic rolls in four‐high hot rolling mills

Abstract

AbstractIn hot rolling mills, bimetallic rolls are used because of the excellent hardness and wear resistance by applying high‐speed steel (HSS) and ductile casting iron (DCI). Because most of the previous studies focused on surface spalling, almost no study is available for internal fatigue failure based on the stress during the rolling. In this study, therefore, a three‐dimensional finite element method is applied to investigate the rolling stress of the work roll in the four‐high rolling mill. A suitable chamfer geometry in the backup roll is discussed as well as the standard wear profile by considering those effects on the fatigue. Then, to evaluate the fatigue risk under compressive mean stress, the fatigue limit lines in the stress amplitude versus mean stress diagram are newly discussed. With the aid of previous experience in industries, the fatigue fracture risk is discussed by focusing on three critical points inside the work roll.