High Performance Greases for Steel Rolling Processes

Lubricating greases are commonly used in machine elements due to easy applicability and overall good performance. As the machinery is exposed to harsh environments, contaminations of the greases are common and may influence the overall performance of the lubricating grease and hence maintenance. In this article the focus lies on water contamination and its effects on grease performance and lifetime in calcium-sulfonate-complex greases. To generate a better understanding of grease-water interaction, basic grease properties such as water absorption and retention were investigated. Further research was conducted on the effects of water on roll stability using a standardized approach in a shear stability tester. The approach was modified to assess the changes after a prolonged time-period. Wear properties were investigated on a four-ball test rig. Lastly the corrosiveness and degradation on grease were investigated on different metal surfaces. The studies carried out provide a better understanding of the effects of water contamination on a wide range of grease properties. The overall performance of the investigated calcium-sulfonate-complex greases is good regarding water contaminations. A significant decrease in performance was only observed at very high water content. Further research on water contaminations will be conducted in future studies using the information gathered in this work as a baseline and reference for other lubricating greases.