Longer roller life, no impact on production, and a full switch of grease within one month.
The customer manufactures seamless carbon and alloy steel pipes and tubes for demanding industrial applications, including boilers, structural systems and fluid transport, where dimensional accuracy and process consistency are critical.
The Size Reducing Mill (SRM) performs the final diameter reduction of the hot pipe. A series of powered rollers progressively reduce the pipe to its specified dimensions while it remains at elevated temperatures.
The roller bearings operate under sustained high radial loads while being continuously exposed to elevated temperatures from the hot pipe. These combined operating conditions place significant demands on bearing lubrication and reliability.
Bearing failure requires the affected roller assembly to be dismantled and replaced, interrupting production and increasing maintenance intervention while reducing overall equipment availability.
Failure history was analysed to identify the frequency and distribution of bearing failures across the roller assembly. Evaluating failure trends, rather than isolated incidents, enabled identification of the underlying reliability issue.
Actual operating loads, bearing temperatures and rotational speeds were assessed under production conditions. This ensured the analysis reflected real-world operating parameters rather than nominal design specifications.
The performance requirements of the application were evaluated against the capabilities of the existing EP2 grease to determine whether the lubricant specification was appropriate for the operating environment.
The combined effects of high mechanical loading and elevated operating temperatures on the elastohydrodynamic (EHL) lubricant film were analysed to understand the mechanism leading to accelerated bearing wear and premature failure.
The root cause analysis determined that the bearing design was not the primary cause of failure. The bearing failures were lubrication-related, with the existing EP2 grease unable to provide sufficient film strength under the application's sustained operating loads and elevated temperatures. The resulting lubricant film breakdown led to increased metal-to-metal contact, accelerated wear, and premature bearing failure.
The tribology experts at Compac recommended Klüberplex MH 41-682 BH, a lithium complex based proprietary grease on a mineral oil base, made for heavy loads at high temperature. Its drop point sits above 280 °C, comfortably above the temperatures these bearings reach in service, which is the margin this application required.
To validate the recommendation under actual production conditions, a controlled one-month field trial was conducted without interrupting mill operations. The specified lubricant was introduced across the roller bearings while the mill continued operating under normal production loads, enabling its performance to be evaluated under the application's true operating conditions. Throughout the trial, Compac's experts monitored bearing performance, lubrication intervals and operational reliability.
The trial demonstrated a reduction in bearing failures of up to 50%, while lubrication intervals increased by up to 2×, extending roller service life without any disruption to production. Based on the observed performance improvements, the customer switched all roller bearings in the facility onto Klüberplex MH 41-682 BH.
Reported by the customer at the close of the trial.
Fewer bearing failures
Longer interval between greasings
Roller life, across the mill
Production time lost
“We had been using EP2 grease for many years. The trial helped reduce bearing failures and increase roller life. We achieved excellent performance without any impact on production and have now completely switched to Kluberplex across all roller bearings.”
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Every application presents a unique engineering challenge. Solving it requires more than replacing a product. It requires understanding the operating conditions, identifying the failure mechanism, and specifying the right technical solution.
Compac has pioneered innovation-led technical solutions for customers across industries for over two decades. By combining global technologies with application engineering expertise, we help manufacturers improve equipment reliability, maximise asset performance, and reduce lifecycle costs. Our support extends beyond implementation through ongoing technical guidance, performance monitoring, and application optimisation.
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