Suitability of vegetable oils as industrial lubricants

Abstract

Abstract This paper reports on the application‐relevant properties of sixteen commercially available vegetable oils tested without additives in accordance with established standards. Their performance was compared with each other and with that of mineral oil and synthetic esters. The basic characteristics of all the oils (density, viscosity, pour point, cloud point, flash point and fire point) were initially determined. A chemical analysis of the vegetable oils was carried out to determine the acid value, saponification and iodine numbers. Additionally, the oxidative stability of all the oils was tested. The tribological performance, lubrication, and wear protection of the oils were judged under abrasive as well as adhesive conditions. The comparative study of the test vegetable oils showed great differences in the properties of the oils. All the vegetable oils tested revealed weak points during testing, including rape seed and castor oils, which have established uses in industry. This study shows that certain vegetable oils, such as sesame oil and wheatgerm oil, may have potential for use in selected technical applications. The mineral oil and synthetic esters showed markedly superior performance when tested under adhesive conditions, but comparable behaviour to the other oils under abrasive conditions.