Effect of sliding speed on friction and wear behaviour of borided gear steels

Abstract

In this study, the wear behaviour of GS18NiMoCr36 (GS18), GS22NiMoCr56 (GS22) and GS32NiCrMo6.4 (GS32) gear steels borided in Ekabor-II powder was investigated by conducting a series of experiments at temperatures of 1123, 1173 and 1223 K for 2 and 6 h. X-ray diffraction analysis of boride layers on the surface of the steels revealed the existence of FeB, Fe2B, CrB and Cr2B compounds. The wear tests were carried out in a ball-disc arrangement under a dry friction condi-tion at room temperature with an applied load of 10 N and with sliding speeds of 0.2, 0.3 and 0.4 m/s at a sliding distance of 500 m. Wear surfaces of the samples at the different sliding speeds were inspected using SEM microscopy and X-ray en-ergy dispersive spectroscopy (EDS). The friction coefficients of the GS18, GS22 and GS32 borided steels varied from 0.41 to 0.59, from 0.42 to 0.58 and from 0.36 to 0.54, respectively. As a result of wear, the friction coefficient was observed to decrease with an increase in the sliding speed of the borided gear steels while an increase was observed in wear resistance.