Analiza właściwości warstwy wierzchniej w procesie tarcia suchego

W opracowaniu przedstawiono zmiany w eksploatacyjnej warstwie wierzchniej w procesie tarcia suchego. Badaniom zużycia poddano powierzchnie obrobione wykańczająco toczeniem, szlifowaniem, nagniataniem tocznym i nagniataniem oscylacyjnym. Zobrazowano zmiany chropowatości w procesie tarcia oraz naprężeń własnych obwodowych i osiowych w warstwie wierzchniej. Ponadto określono zmiany mikrotwardości warstwy wierzchniej.

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The paper presents variations in the service upper layer in the dry friction process. Surfaces finishing worked by turning, grinding, rolling burnishing and oscillatory burnishing were investigated. Roughness variations in the friction process and changes in hardening and internal peripheral and axial stresses in the upper layer are illustrated. Tests were carried out for a tribologic pair of toughened steel 55 and cast iron ZL200. As a result of the process of technically dry friction over a path of 20,000 m, wear variation patterns were obtained. The greatest wear occurred for the turned surface, and the least for the oscillatory-burnished surface. Also, variation in the magnitude of peripheral (along the surface perimeter) and axial stresses is presented. For each case examined, a change in the value of stress occurred, with the largest changes resulting for burnished specimens notwithstanding the fact that in those upper layers after the burnishing process compressive stresses were the greatest. As a result of the plastic strains of micro-areas participating in the friction process, an increase in the microhardness of sub-surface layers resulted, as compared with the hardness of the original material.