Study On Extreme Pressure Performance Optimization Of Complex Lithium-Calcium Based Grease

With the continuous improvement of socialization,mechanical equipment is gradually developing in the direction of high speed,heavy load and miniaturization,and grease provides a guarantee for the stable and reliable operation of various mechanical equipment.In this paper,the tribological properties of lithium complex grease containing different additives and lithium sulfonate calcium complex grease containing different proportions of calcium and lithium soap were investigated by using a four-ball friction and wear testing machine,and the research content and results are as follows:1.Composite lithium-based grease was prepared by using polyalphaolefin(PAO40)as the base oil and lithium hydroxide as thickener,and graphite(GF),molybdenum disulfide(MoS2),isobutylene sulfide(T321)and trimethylphenol phosphate(T306)as additives,and the influence of additives on the tribological properties of composite lithium-based greases was investigated.The experimental results show that GF and MoS2 compounds can improve the friction and anti-wear properties of grease,while T321 and T306 significantly improve the extreme pressure performance of grease.The four additives are compounded in the right proportions for the best friction and wear resistance and load-bearing capacity.2.Compound lithium sulfonate calcium grease was prepared with polyalphaolefin(PAO40)and calcium petroleum sulfonate(T106D)as the base oil,lithium hydroxide and calcium hydroxide as thickeners,and the effect of the ratio of calcium soap and lithium soap on the tribological properties of the grease was investigated.The experimental results show that when the ratio of calcium soap and lithium soap is 4:6,the grease has the best friction reduction performance.When the ratio of calcium soap and lithium soap is 9:1,the grease has the best anti-wear performance;The extreme pressure performance of the grease increases with the increase of calcium soap content.3.Build a prediction model of particle swarm(PSO)optimization random forest(RF)algorithm to predict the friction and wear performance of grease.The prediction results show that the prediction results of the PSO optimized RF model are good,and the prediction accuracy R2 for the friction coefficient and grinding spot diameter reaches 0.878 and 0.914,indicating that the PSO optimized RF model has good prediction accuracy.