Wear and Contact Temperature Evolution in Pin-on-Disc Tribotesting of Low-Metallic Friction Material Sliding Against Pearlitic Cast Iron

Pin-on-disc tribotesting is widely used to investigate the sliding behaviour of materials, including friction materials used in braking systems. The evaluation of the average contact temperature is paramount to understand the acting friction and wear mechanisms, and to determine the role of the materials. In the present work, the tribological behaviour of a commercial low-metallic friction material during dry sliding against a pearlitic cast iron has been investigated and the evolution of pin and disc temperature was recorded. The temperature distributions in the pin and the disc were modelled using a finite element analysis with three different approaches, i.e. considering a perfect contact, the separated bodies concept, and the presence of a third body between the sliding surfaces. The results were then discussed by considering the damaging phenomena occurring at the sliding contact. Wear was found to be nearly mild in nature in agreement with the contact temperatures that were determined to be lower than 100 degrees C. During sliding, a limited third body was formed, made of a partially covering friction layer on the pin surface, and a thin and irregular oxide layer on the cast iron wear track. The approach based on the perfect contact with thermal continuity at the interface was found to better fit the experimental temperature records and to be in substantial agreement with the observed wear phenomena occurring at the pin-disc interface.