Effect of Microstructures on the Tribological Performance of Medium Carbon Steel

Abstract

Improving wear resistance and reducing the coefficient of friction of the cylinder liner are critical to improving the service life and energy savings of internal combustion engines. In this paper, the effect of the characteristics of cementite precipitation on the tribological performance was studied using a medium carbon steel (AISI 1045 steel), which can be used to make cylinder liners. Three kinds of microstructures with different characteristics of cementite were obtained by heat treatments. Abrasive wear tests and dry sliding friction tests were conducted on the samples of each microstructure. The study indicated that the abrasive wear resistance of medium carbon steel mainly depends on its hardness rather than on the characteristics of cementite precipitation. However, increasing the hardness alone did not guarantee improvement of the dry sliding friction performance of medium carbon steel. The specimen with a spherical pearlite microstructure, which was granular cementite distributed in the ferrite matrix showed the best friction performance. Moreover, the abrasive wear mechanism and dry sliding friction mechanism were discussed. In the end, the correlation between the characteristics of cementite and tribological behavior was established. These findings can help develop multiphase materials with outstanding tribological performance.