A Master Curve for the Shear Degradation of Lubricating Greases with a Fibrous Structure

Abstract

In this article, the mechanical aging behavior of lubricating greases with a fibrous structure is studied by aging fresh samples at controlled shear rates and temperatures in an in-house-made Couette aging machine. The rheological properties of fresh and aged samples were evaluated in a plate–plate rheometer. In the absence of oxygen, no chemical reactions occurred. The results showed that shear degradation is accelerated by increasing the temperature. This thermal effect can be described by an Arrhenius law. A grease aging master curve was created to describe the influence of shear and temperature on the mechanical aging of fibrous structured grease. Next, the model was validated using a conventional grease worker test. Finally, the model was applied to full ball bearings using an R0F + bearing test rig. The master curve forms an important contribution to the development of grease life models.