Improvement Effect of Green Lubricants on the Tribological and Mechanical Performance of 4140 Steel

Although much has been learned and investigated about environmentally friendly lubricants in recent years, several issues remain critical to their use in specific applications. A key point that could be limiting their utilization is that the effect of green lubricants on the tribological and mechanical properties of the elements has not been thoroughly studied since such attributes determine their performance in industrial applications. For this reason, in this research, the effect of green lubrication on the tribological and hardness properties of AISI 4140 steel was studied. The performance of three bio-based lubricants was studied and compared to that of five of the most representative lubricants. First, the lubricants were chemically and physically characterized. Then, the effect of each lubricant on the friction and wear behavior of the system was analyzed by kinetic friction coefficient, wear rate calculations, and microhardness measurements. In general, the bio-based lubricants exhibited the lowest values of friction and wear. Further the mechanical properties of the systems lubricated by these lubricants were not affected or were affected to a lesser degree.