No abstract

This paper presents the results of research into the effect of the use of an additive to the lubricating oil SAE 15W/40 on the lubricating properties (standardised tests), i.e. the weld point Pz, last non-seizure load Pn, load-wear index Ih, and seizure load Pt. The friction pair consisted of four balls and the tested lubricant. Moreover, the impact of the use of the lubricating oil (non-standardised tests) on tribological properties such as friction force, wear, and the temperature of the friction area for the friction pair C45 steel/210Cr12 steel, was explored. The additive contained copper and lead particles of the size of a few micrometers. The tests helped to determine the effect of the use of the additive to the lubricant on the formation of the operational surface layer. The results were used to build a model of the boundary layer formed as a result of the additive to the lubricating oil.

Purpose -The aim of this study was to evaluate a surface layer of the condition resistance to seizure. The surface layer was shaped in the processing grinding and burnishing. Design/methodology/approach -The resistance to seizure tests were carried out on a test station specially designed by the author. It is possible to simultaneously test the same two pairs of pivot-pan kinematic pairs on this station. Moreover, the time, route and the temperature of the friction area were registered. The time of sliding group operation from the moment when a lubricant is no longer added to the friction pair to the moment the sliding group reaches the critical temperature T ϭ 418 K (145°C) is taken as a seizure indicator. Findings -The structure and state of the surface layer have an influence on the seizure of the surface of cooperating elements. Greater resistance to the seizure of the burnished surface in comparison to the ground surface is associated with differences in the state of the surface layer. The burnished surface has a smaller surface roughness and a higher value of the bearing surface curve, and the compressive stress occurs more often in the surface layer. Originality/value -There have been no studies on the effects of burnishing machining and grinding of cast iron in resistance to seizure.