Friction and wear study on patterned bearing steel using a milling machine

Bearings, which are widely used in the industry, require high-energy efficiency and durability, and research toward frictional wear improvement is in progress. In this study, micropatterns were fabricated on the surface of an STB2 bearing steel. Three types of line-shaped micropatterns with intervals of 40, 80, and 150 μm were processed using a milling machine. In addition, the friction efficiency was assessed by measuring the friction coefficient of a bare sample with a diamond-like carbon (DLC) thin film, which has excellent friction efficiency. The friction wear efficiency was further analyzed by comparing the change in friction coefficient and the wear area as a function of the pattern interval. As a result of the wear test, the STB2 specimen to which the pattern was applied showed a difference in the friction coefficient according to the pattern pitch, and the lowest coefficient of friction was shown at 40 μm with the smallest pattern pitch, which confirmed that the distance between the pattern pitches affected the friction characteristics.