Study of the Steady-State of Wear in micro-abrasive wear tests by rotative ball conducted on specimen of WC-Co P20 and M2 tool-steel

Since its introduction to scientific community of tribologists, the micro-abrasive wear test by rotative ball has been adopted by renowned universities and research centers. In this type of experiment, an important tribological phenomenon that must be observed and considered is related to the attainment of the Steady-State of Wear, characterized by stabilization of the coefficient of wear as a function of the test time. In this context, the purpose of this work was to evaluate the attainment of the Steady-State of Wear in specimens of WC-Co P20 and M2 tool-steel, during micro-abrasive wear tests by rotative ball. Completing the tribological system, have been used spheres of AISI 52100 steel and an abrasive slurry prepared with black silicon carbide (SiC) and distilled water. One value of normal force and different values of test times have been defined and, during the experiments, the abrasive slurry has been continuously agitated and dropped between the sphere and the specimen. After testing, all wear craters generated have been analysed by optical microscopy, in order to measure the respective diameters and verify the micro-abrasive wear modes acting on their surfaces. For the established test conditions, it was observed that the Steady- State of Wear has been obtained with the specimen of WC-Co P20, due to the constant behaviour of the coefficient of wear along the test time; however, the Steady-State of Wear has not been obtained for the M2 tool-steel, in which has been observed the variation of the coefficient of wear as a function of the test time. Finally, in this study also has been concluded that the Steady- State of Wear is not a property of the material and this phenomenon is strongly dependent on the materials of the tribological system and of the imposed tests conditions.