A collaborative Bearing Failure Analysis conducted by SKF and Authorised Distributor, Bearings Services Durban, at one of South Africa’s leading sugar refinery plants in KwaZulu-Natal, provided tremendous value for the customer. In addition to offering a clear understanding of the root cause of the failure, coupled with corrective practices for future prevention, the analysis also provided insights into how various other factors can contribute to premature bearing failure.
The Tongaat Hulett Refinery plant located in Rossburgh, Durban, experienced significant downtime on their production line, due to a premature bearing failure on a mainline pump. The Refinery’s Maintenance Engineer, Adarsh Madanlal,
explains that the pump tripped and refused to start. “Upon removal and stripping, we noticed that the bearing had failed.
“Furthermore, a day after commissioning, a high frequency noise was detected and the oil turned black. Despite draining and changing the oil every Thursday, it kept turning black the following day. After evaluating all plant conditions, we were unable to determine the root cause of the bearing failure as all available evidence was inconclusive.”
Root cause
The refinery subsequently reached out to their trusted partner of the past thirteen years, SKF, in August 2024, for assistance. “It was evident that understanding the root cause of these repeated bearing failures was critical to enable our customer to effectively resolve the issue,” asserts Shaniel Rambally, Bearings Services Durban Branch Manager – Coastal & Midlands Region.
“In short order, we recommended that an ISO Bearing Damage Analysis be performed on multiple bearings. Upon acceptance by the refinery team, the bearings were duly collected and sent to SKF for analysis; the ensuing report was completed and forwarded to our customer shortly afterwards, achieving an impressive turnaround time of between 10 to 12 working days!”
Rolling contact fatigue
Based on the information provided and the condition of the bearings, SKF specialists concluded that the root cause of the damage could be classified according to the ISO Failure Mode Classifications ISO/15243 as rolling contact fatigue failure type.
Titus Kasie, SKF Territory Sales Manager – East Coast & Zimbabwe, explains that rolling contact fatigue is caused by repeated stresses that develop in the contacts between the rolling elements and the raceways. “Fatigue manifests visibly as a change in the structure (microstructure) and is as a result of inadequate lubrication conditions (inadequate lubricant film thickness).”
Valuable insights
Adarsh and his team were thoroughly impressed by the ‘astoundingly detailed’ results and feedback they received from SKF. “The comprehensive, fact-based report provided an in-depth breakdown of the findings. It was also presented in clear detail, making it easily interpretable even for those without expertise in this particular field.”
He also emphasises that the value of this investigation went beyond identifying the root cause of the failure; it provided valuable insights into corrective practices, helping to mitigate the risk of similar issues in the future. “The report also gave us a good understanding of how other factors can contribute to premature bearing failure.”
Constructive outcome
Adarsh further notes, “While bearing failure analysis is a specialised field that is not widely recognised, its importance is evident from this constructive outcome, particularly in FMCG plants, where it plays a crucial role in optimising operational efficiencies. We wish to see these services being fully utilised by more plants and industries in the future. Overall, we complement Bearing Services and SKF for their exceptional customer service and high level of quality products.”
