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makes a good starting point, as it looks at structural stability under shear and thermal loading. With a positive result here, any other tests deemed critical to the end application can then be carried out to ensure the mixture demonstrates all relevant characteristics.
Grease longevity
Once satisfied that the new grease (or grease mixture) delivers the necessary performance, it’s important to check that this can be maintained throughout its lifetime. Field trials that include regular grease analysis offer the best proof.
Field trials need careful planning and management to ensure they are relevant to the application and give robust, meaningful results. Brand new components must always be used if causality is to be clear. A high number of trial candidates makes good sense: statistically, a bigger sample can help to balance out any anomalous results and compensate for things that may go wrong. Field trial parts can get discarded and replaced during routine servicing; vehicles and pieces of equipment can get sold or scrapped by mistake; anything can happen!
Independent assessment and validation of components at the end of a field trial are also vital for minimising potential bias. This gives additional reassurance alongside lab testing: not just for the equipment owner seeking to switch grease, but for equipment builders and OEMs whose approval may also be sought.
Real world validation Working in close partnership with OEMs, Afton has carried out relevant field trials using this new, lower thickener content CS grease. After performing successfully in an extended truck wheel bearing trial in the harsh Indian climate, the new grease was challenged to protect the hot roller bearings in a steel mill. Here, the structural and thermal stability of the grease is vital given its constant exposure to high loads, intense heat and splashing water.
The field trial CS grease was formulated with an appropriate additive package to support optimal performance under extreme operating conditions. Extended structural stability testing was carried out to investigate the grease’s laboratory performance, including 4-ball weld and wear, roll stability and work penetration tests. Low thickener CS grease matched or outperformed the incumbent lithium grease in all bench tests, so entered the trial phase.
Figure 1: The extreme operating conditions in a steel mill
With lithium complex grease, the hot roller bearings required regreasing 3 times per day and replacement every 10 days. Switching to CS grease not only lengthened the regreasing interval almost tenfold from 8 to 72 hours, it also extended the bearing lifespan from 10 to 60 days. This represents significant savings in grease as well as maintenance costs and even more importantly in missed production avoidance. These results were replicated in a second steel mill.
Performance payoff
When the right calcium sulphonate grease is employed, real-world savings are achieved through its unique performance strengths, namely through lowering costs of equipment maintenance (e.g. bearings) and increased productivity (less downtime via the less frequent re-greasing).
Using its expertise in close partnership with end users and OEMs, Afton offers relevant, replicable testing and trials that combine to give all stakeholders the reassurance they need.
How soon could you reap the double benefits of switching to the right CS grease?
Figure 2: Calcium sulphonate grease in use in automotive applications
www.aftonchemical.com
LUBE MAGAZINE NO.174 APRIL 2023
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