Friction Modification of Steel/Steel Interface for Effective Motion under High Load and Pressure

Abstract

The friction modification of AISI 52100 on AISI 8620 interface for effective motion was examined in this study. Friction, as a major industry challenge, costs Nigeria about 5% of its gross national product. Hence there is an urgent need for its mitigation. Avocado (Persea Americana) and watermelon (Citrulluslanatus) seed oils were the bio-lubricants enhanced in this study to modify friction for effective motion. The ball-on-disc tribometer was used to characterize the tribological behaviour of the samples. The mean friction coefficient (COF) of the moderate 80N lubricated condition was observed to be within the range of 0.123 to 0.50, with watermelon seed oil proving a better tribological response. However, at elevated loading conditions of 120N to 300N, a decrease in the friction coefficient of about 0.4 was observed, showing a drastic reduction in friction which occurred only in avocado seed oil. The tribochemical reaction of the iron and oxygen-produced Fe₃O₄ was responsible for the reduction in friction at the boundary lubrication regime. This confirms that extremely high-pressure conditions are necessary to generate a tribochemical coating on the steel surface, which is needed to reduce friction. Furthermore, this work has shown the effectiveness of several modified native vegetable oils for boundary lubrication.