Investigation of the effects of skewness Rsk and kurtosis Rku on tribological behavior in a pin-on-disc test of surfaces machined by conventional milling and turning processes

Abstract

Friction and wear are influenced by the surface conditions of the material, since there is deformation, segregation, generation of oxide films, among others. Roughness is an important characteristic in tribological studies, where the parameters of skewness and kurtosis have greater influence than the conventional parameters R a and R q. This study is aimed to investigate the influence of the parameters of skewness R sk and R ku kurtosis on the surface of the USI AR 360 steel machining by the milling and turning processes in the pin-on-disc sliding wear test. Results showed that surfaces with the same R a and R q could be distinguished by the skewness parameter. Different behaviors were observed in the analysis of friction curves, where the skewness effect showed a tendency to reduce the friction coefficient. It was also observed that the feed marks orientation in relation to the sliding direction can influence the tribological behavior of the surfaces.

Sliding abrasive wear when combining WEDM conditions and polishing treatment on H13 disks over 1045 carbon steel pins

“…Using the Archard equation [32], the K value was obtained by calculating the wear rate. The total arithmetic average values were between 8.9E-11 and 1.4E-10, similar to Ba et al [38]. The values were lower than the value considered "moderate wear" (K between 1E-8 to 1E-4), according to Bhushan [39], with a wear coefficient K in the order of 1E-10.…”

Study on the Tribological Behavior of Wear and Friction Coefficient on AISI M35 High-Speed Steel with and without DLC Coating

“…The behavior of the friction coefficient observed in tests 1 and 2 with AISI M35 steel without coating is similar to the behavior presented in tribosystems composed of metallic surfaces in contact and relative movement with no lubrication. The friction curve can be explained as follows 20 : the running-in regime can be separated into three stages. In the first stage, given the beginning of the relative movement, the removal of the superficial layer occurs, the increase in adhesion due to the increase in the cleaning of the interfacial areas, the increase in the interaction between the roughness and the worn particles, which may gradually increase the value of the friction coefficient.…”

“…Friction and wear are considered as properties dependent on each formed tribosystem, which involves environmental conditions (humidity, lubrication and temperature), hardness ratio of the materials, roughness of the surfaces in contact, metallurgical compatibility of the materials, formation of debris and oxides, contact pressure, among others 11,15,20 .…”

Análise do comportamento do par tribológico aço alto carbono e alto silício (HC-HSi) contra pinos com substrato de metal duro e cermet em ensaios de pino sobre disco

“…Os valores do µ até essa distância (150 m) foram em torno de 0,23; 0,41 e 0,28, respectivamente. As flutuações podem estar atribuídas a presença de debris, que ocasiona instabilidade da curva do coeficiente de atrito, devido à deformação e quebra das asperezas, como reportado por Ba et al (2021), visto que no run-in as superfícies em contato ainda estão se acomodando (BLAU, 2009). Posteriormente, os debris são removidos da interface e uma área de contato real pode ser formada, terminando e estabilizando o atrito Ba et al (2021).…”

“…As flutuações podem estar atribuídas a presença de debris, que ocasiona instabilidade da curva do coeficiente de atrito, devido à deformação e quebra das asperezas, como reportado por Ba et al (2021), visto que no run-in as superfícies em contato ainda estão se acomodando (BLAU, 2009). Posteriormente, os debris são removidos da interface e uma área de contato real pode ser formada, terminando e estabilizando o atrito Ba et al (2021). Além disso, as maiores instabilidades podem estar relacionadas a maiores valores de Ra verificada para os pinos de cermet após revestimento.…”