Fractographic study indicates that the LPTR disc in question had failed by overload. All fracture features were typical of fast fracture and there were no evidences of delayed failure like fatigue. It appears most probable that during 6001st to 6006th cycle, the furnace had moved from its position rearward leading to impact of the furnace body with the rotating disc with subsequent disintegration of the LPTR disc. The lateral shift of the furnace rearward took place due to failure of the furnace fixing mechanism. It appears that due to wide difference in hardness between the bolts and nuts/locknuts, it would not have been possible to torque tighten the furnace assembly rigidly or the threads on the nuts/locknuts got damaged during tightening. The movement of the furnace appears to be the first in the chain of events. The other damages including the fracture of the LPTR disc appear to be secondary in nature and subsequent to the primary failure.