The viscosity of a fluid is its resistance to flow and is highly influenced by temperature. It decreases with rising temperature, i.e. the fluid becomes more liquid. However, the change is not linear to temperature, but shows a double-logarithmic relationship. This relationship, which was described by Ubbelohde and Walther, refers to mineral oils and, in the first approximation, can also be used for synthetic oils.
Operating viscosity of lubricants
The operating viscosity for oils and bases oil of lubricating greases from Klüber Lubrication can be determined approximately by means of the known kinematic viscosity at 40 °C and 100 °C. The viscosity of a lubricant (taking into account loads, speed, etc.) is one of the indicators for lube film formation protecting against friction and wear. Synthetic oils, special additives and various thickener concepts enable the lubricating film to be formed already at a lower, energy-efficient viscosity