LUBE MAGAZINE
Novel Calcium Sulphonate grease exceeds in unexpected places Chris Pether, Customer Technical Support Chemist, Industrial Lubricants, Afton Chemical Ltd
An innovative new manufacturing method delivers a lower soap calcium sulphonate grease that outperforms lithium complex grease, protecting production machinery for extended periods in extreme environments. With global lithium demand and cost set to keep rising, Afton Chemical has been exploring further application areas for this new grease. Field trials show strong performance in truck wheel bearings, for which conventional calcium sulphonate grease is not always suitable. With vehicle electrification being prioritised by governments and original equipment manufacturers (OEMs) worldwide, more and more lithium is needed to manufacture the huge numbers of batteries required from an industry that has limited capacity to supply. This has caused the price of Lithium hydroxide to skyrocket with the forecast for the next 5 years showing little sign that supply will ever catch up with demand. The lower and more stable cost of conventionally produced calcium sulphonate grease makes it an increasingly attractive alternative to lithium, although its properties are not suited to all applications. Around 90% of the heavy duty wheel bearing market is currently using lithium complex grease, as it has offered a good balance between performance and cost. Now, conventional calcium sulphonate grease shows high shear stability and excellent water resistance, and it also possesses a very high load carrying capacity – all of which make it appear suitable for use in wheel bearings. However, the high soap content of conventional calcium sulphonate grease makes it susceptible to hardening in wheel bearings exposed to a constant chemical and physical onslaught of heat, shear, shock loading, water and debris.
LUBE MAGAZINE NO.168
APRIL 2022
Issues around hardening in wheel bearings have finally been resolved by a patented new grease production process. This method results in lower soap calcium sulphonate grease that outperforms lithium complex grease. In addition to the direct cost saving by using less soap, this grease technology excels at protecting equipment in extreme operating environments, such as steel mills, and this strong performance has now been proven to extend to truck wheel bearings. Afton Chemical compared their lower soap grease with three different wheel bearing greases currently in use in trucks, including a high-performance synthetic lithium grease. The calcium sulphonate candidate grease outperformed them in many parameters, showing excellent structural stability with significantly lower oil separation than the other three test greases. It also delivered much greater protection from shock load and wear in the 4-ball weld test; had one of the lowest losses on the water washout test; and caused the least hardening to nitrile rubber seals – the most common type used in wheel bearings – with minimal seal volume increase. Cup Race
Cone Race
Figure 1: Example of the bearing parts at 120,000km.
This superior lab performance translates to the real world as shown by a recent OEM field trial in India. With the challenging climate and rough terrain, the wheel bearings on Indian trucks have to deal with
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