This paper presents the outcome of the measurement of the tribological characteristic of O-ring seals in the event of operating in conditions with a lack of lubrication. The measurement was carried out on a seal and rod model. The measurement was carried out during the condition of the round cross-section seal sliding on the surface of the piston rod. We analyzed how the friction force during rod movement, which resulted from the cooperation of the sliding nod and the rod, was changing. The experiment was conducted for various rubber materials. The aim of the research was to evaluate the friction reducing capability of graphite in rubbers of commercial sealing parts. Typical materials used for the seal and the materials, which contained the filler in the form of graphite powder, were compared. Synthetic graphite powder with a particle size of 1-2 µm was applied, and nitrile rubber (NBR) and fluoroelastomer (FKM) were compared as typical materials for O-ring seals. In the case of the two tested materials, the addition of graphite powder had an influence on the decrease in the friction force. , depending on the type and structure of the filler, the character of material wear changes [22].Research is conducted with the aim of creating materials with better functional characteristics. A lot of various kinds of fillers are studied. The developed new materials find application in various spheres of the industry. The fillers can have different forms. Although, based on the analysis in the literature, one can infer that, in general, carbon-based materials are widely applied as fillers. The fillers introduced into rubber can significantly improve many properties of the material. Even at a relatively low quantity of the applied filler, the mechanical, thermal, and electrical properties of the elastomeric matrix can be improved. Depending on the choice of the type of filler, properties such as tensile strength, elongation at break, and thermal oxidative stability can be improved. They also enable the change of properties such as the friction coefficient and specific wear rate in the case of materials used as the elements, which need to perform relative movement. Various kinds of rubber such as isobutylene-co-isoprene (IIR), polychloroprene (CR) [23], silicone rubber (SR) [24][25][26][27], ethylene-propylene-diene rubber (EPDM) [28,29], petroleum resin, and nitrile rubber (NBR) [30][31][32] are used as a matrix material. In the literature, one can come across broadly discussed research results on the application of carbon-based materials as filler [33][34][35][36].Scientists are also interested in the methods of material optimization, including reinforcement application. The identification and description of the complex structures obtained in this way is a complicated issue [37,38].The research associated with O-ring seals, described in the literature, refers to their reliability. The mechanical behavior of chosen materials, taking into account both static and dynamic strain [38][39][40], is checked during the tests. The inf...

The present study discusses the influence of engine oils on the tribological parameters of sliding couples with laser borided surface layer. The borided layer was formed on specimens made from AISI 5045 steel by laser remelting of a surface layer coated with amorphous boron. The sliding friction and wear process was carried out on the pairs with AISI 5045 steel and SAE-48 bearing alloys which were lubricated with 5W-40 and 15W-40 engine oils. The investigation showed significant differences in the friction coefficient and temperature in the tested pairs with the laser borided surface layer. In the couples lubricated with 5W-40 engine oil, the tested parameter of friction was higher than in the couples lubricated with 15W-40 engine oil. The couples lubricated with 5W-40 engine oil showed more intensive wear of SAE-48 bearing alloy in contact with the laser borided surface layer than the pairs lubricated with 15W-40 engine oil. The laser borided surface layer used in friction pairs leads to the destruction of the lubricating properties of engine oils and reduces its resistance to scuffing.

The present study discusses the influence of laser borided surface layer on the parameters of sliding couples lubricated by engine oil. The borided layer was created by laser remelting of a surface layer of steel samples coated with amorphous boron. The study of friction, wear, and lubrication was conducted on the pairs made of steel AISI 5045 and SAE-783 and SAE-48 bearing alloys which were lubricated with 15W/40 engine oil. The research showed important differences in the friction coefficient and temperature in the tested couple with laser borided surface layer. In the couples containing the counterparts with SAE-783 bearing alloy, the tested parameter of friction was higher than in the couple composed of counterparts with SAE-48 bearing alloy. The counterparts with SAE-48 showed more intensive wear in contact with the laser borided surface layer than the counterpart with SAE 783. The process of friction at the contact area of the sliding couple with laser borided surface layer leads to the destruction of the lubricating properties of 15W/40 engine oil and reduces its resistance to scuffing and seizure.

No abstract

No abstract