Performance Considerations in Formulating Multi-Purpose EP Greases Vasu Bala and Jim Hunt Tiarco Chemical, Dalton, GA USA Abstract This paper discusses three studies of effects of additives on performance properties of greases. Three base greases were studied: two lithium complex thickeners and one calcium sulfonate thickener. The additives were conventional EP (extreme pressure), anti-wear and corrosion inhibitor additives. Greases were tested for effects of individual additives and combinations of additives on weld loads in four-ball EP tests, wear scar diameters in four-ball wear tests and performance in copper corrosion tests. This paper shows that it is possible to use additives to optimize and balance these performance properties. This study was motivated by performance trends for EP greases and formulation considerations to meet and balance performance requirements for load bearing, wear and yellow metal corrosion. This paper includes background information that highlights important formulation considerations such as current sourcing demands for key raw materials used in thickeners. Additional formulation considerations include Original Equipment Manufacturers’ (OEM) requirements, current global supply chains, and possible changes that may be required to provide alternate greases and support new approvals. Supplies of key raw materials and anticipated future OEM requirements are driving the development of new grease formulations and encouraging manufacturers to consider alternate chemistries to ensure long-term sustainability of greases for industrial and automotive markets. Outline I. II. III.
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Introduction Grease Market Breakdown, Drivers and Trends Grease Classifications and Specifications A. General Grease Properties B. ASTM D4950 Standard Classification and Specification for Automotive Service Greases C. SAE J310 D. ISO Standards E. DIN 51825 F. JIS K2220 Studies of Grease Additives and Interactions A. Grease Formulation B. Properties of Greases and Additives Used in This Study C. Study 1: Effects of EP and Corrosion Inhibitor Additives in Lithium Complex Grease D. Study 2: Effects of EP, Corrosion Inhibitor and Anti-Wear Additives in Calcium Sulfonate Grease E. Study 3: Effects of EP and Corrosion Inhibitor Additives in Lithium Complex Grease Conclusions Acknowledgements References -6NLGI Spokesman | VOLUME 84, NUMBER 4 | September/October 2020
