Study on Damage Behavior and Failure Mechanism of Rollers

Rollers are important parts of rolling mills. The annual overhaul or maintenance after failure greatly affects production efficiency, waste of resources, and even economic benefits. The failure modes were discussed by studying the damage behavior of rollers in service. The results show that the failure behavior of rollers is mainly fatigue flaking, crack and fracture, which result from manufacture, use and their co-effect. Fatigue flaking is due to local excessive stress and heating up. Micro cracks forms at the subsurface and expands, leading to flaking pits. Cracks result from the co-effect of thermal cycle stress and plastic strain. Fracture is mostly due to larger loads and often occurs that at the stress concentration region of the neck or at the subsurface with defects. According to different failure mechanisms of rollers, process improvement is carried out and proper repair cycle is established. Combined with scientific and effective detection methods, a solid foundation can be laid for effective use and life increase of rollers.