Correlation of microstructure and thermal fatigue property of three work rolls

Three centrifugally cast work rolls, the nickel-grain cast-iron roll (Ni-grain roll), the high-chromium cast-iron roll (Hi-Cr roll), and the high-speed steel roll (HSS roll), were studied to determine their thermal fatigue property and microstructure and the effects of an increase in tensile stress. Fatigue testing showed that thermal fatigue property was best in the HSS roll, followed by Hi-Cr roll and the Ni-grain roll. The fatigue life of each roll decreased with the increase of mean temperature or temperature range of the thermal fatigue cycle. The results were interpreted based on the amount of primary carbides and cyclic softening associated with exposed time to elevated temperatures.