Determination of the low temperature performance of lubricating greases - correlation of methods (Starting torque, flow pressure and flow point)

摘要

Test methods IP 186 and ASTM D 1478 (Determination of low temperature torque of lubricating grease) respectively have proved to be useful test methods over the years. So did the flow pressure method DIN 51805, mainly used in Germany as a national method. Today these methods are being substituted or completed more and more by rheometer methods, which are more meaningful and less time and staff consuming. The aim of this study is to show a correlation of these methods, to make results obtained by conventional and modern rheometer methods comparable. This paper presents results on model greases representing three different types of thickeners (lithium-12-hydroxystearate, highly dispersed silica and diurea). The model greases were made of four different types of base oils (PAO/mineral oil, PAO, ester and polypropylene glycol) showing different chemistry and polarity. NLGI classes have been varied as well.