Continued from page 19


Greases were tested for their lubrication capacity before and after the UV ageing process. The first general conclusion shows the major impact of base oil which can create (as seen in Figure 8) gumming or solid layer that will lead to a dramatic increase of CoF. This is a major issue for the end-user as it could block switch-plates for instance.


Figure 11. Thickened Biobased A, B & C SRV wear results.


Figure 9. CONDAT Railway Lubricants aspect before and after UV test.


LUBRICATION CAPACITY The lubricating capacity is measured by a SRV tribometer according to ASTM D5707 (see Figure 10). We monitor the variation of coefficient of friction (CoF).


Figure 12. CONDAT Railway Lubricants SRV wear results. CONCLUSIONS


For the biodegradable greases’ railway market, the main characteristics are certainly resistance to UV, Oxidation and Lubricity. To ensure optimal performances, the best solution seems to be ester base, offering better characteristics than basic vegetable oils. Base oil is part of the formulation, another important part is linked to the use of the right blend of additives, either to protect equipment or to adhere on the surface to ensure the perfect availability of the grease. Additional tests can be carried out with manufacturers equipment for the railway market, such as for example spraying tests for onboard systems. A formulation is always a result of a compromise between performances and cost.


To conclude, Environmental concerns should lead to a major use of these biodegradable greases, which already demonstrate a high level of performance.


Figure 10. ASTM D5707 conditions and SRV test.


LINK www.condat.fr


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LUBE MAGAZINE NO.150 APRIL 2019


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