Tribological Fracture of Ferritic-Pearlitic Steel with Nano and Submicron Structure during Sliding Friction

Abstract

An urgent task of tribology is to study the wear mechanisms of various materials for the development of stable wear-resistant microstructures and optimal modes of their production. The purpose of this work is to assess the wear resistance of low-alloy steel with a submicrocrystalline ferritic matrix, reinforced with nano- and microspheres of cementite, as well as to reveal the features of its destruction by friction based on the analysis of friction surfaces. Steel nanostructuring was carried out using cold (at room temperature) equal-channel angular pressing and subsequent annealing. The process of steel wear in coarse-grained and nanosubmicron states has been studied at various stages of tribological loading under sliding friction conditions using optical and scanning electron microscopy, profilometry, and analysis of changes in the roughness parameters of friction surfaces. It is shown that the formation in steel of a heterogeneous structure “submicron ferrite matrix - nanoscale carbide phase” provided an increase in wear resistance by more than two times. The features of contact fracture are revealed, which determine the increase in the wear resistance of steel upon refining the structure and indicate significant differences in the nature of the metal tribological strength formation, depending on the level of dispersion of microstructural elements. The results obtained can be used in the development of technological processes for the formation of nanoscale structural components and improving the properties of traditional low-alloy steels.