Interfacial slip verification and slip defect identification in shrink-fitted bimetallic sleeve roll used in hot rolling mill

Shrink-fitted sleeve rolls have several advantages including the ability to reuse shafts by replacing worn sleeves and the ability to apply to next-generation rolls. However, the authors' previous simulation showed a "nonuniform slip" may appear between the shaft and the shrink-fitted sleeve even under free rolling and when no overall uniform slip condition is satisfied. In this paper, the rolling experiment is conducted by using a miniature rolling mill to verify the slip phenomenon realized by the numerical simulation. To understand the phenomenon, the slip defect formation and the slip growth are investigated by observing the slipped surfaces in detail. It is found that the slip defect starts from the contact of the surface roughness where the width of the defect coincides with the pitch of the machining feed. Eventually, the slip defect is developed by erosion wear and cohesive wear during the rolling and finally forming a large oval-shaped erosion groove at the end of the scratch. Finally, the fatigue strength of the sleeve roll is evaluated by considering the slip defect geometry observed from the experiment.