Root Cause Failure Analysis of Pinch Roll Bearing at Hot Strip Mill

Bearings are one of the most widely used and highly stressed engineering components. If properly manufactured, mounted, operated and maintained, they can give excellent service life. However, they may suffer from premature failure due to multitudes of reasons. Current work deals with pinpointing failure mode and root cause analysis of a pinch roll bearing at coil box of a Hot Strip Mill. Macroscopic and microscopic analysis revealed that bearing failed in Rolling Contact Fatigue mode. All metallurgical, mechanical and maintenance factors that might contribute to rolling contact fatigue were analyzed independently. It was concluded that misalignment led to accelerated Rolling Contact Fatigue. Striation marks rarely reported for rolling contact fatigue of bearing steels were observed to confirm fatigue mode of failure. Recommendations for preventing similar failures in future have been provided.