EVALUATION OF THE CORRELATION BETWEEN HARDNESS AND STRUCTURE OF ALLOYED CAST IRON WITH FLAKE GRAPHITE, USED FOR MANUFACTURING PISTON RINGS

The study objective is to provide practical confirmation to the correlation between hardness and structure, namely, graphite phase parameters, in oil blanks of piston rings. The task to which the paper is devoted is to analyze the results of hardness measurement and evaluate their interconnection with the dimensional parameters of graphite phase in alloyed cast irons used for manufacturing oil blanks of piston rings. Research methods: theoretical analysis of references related to the research topic, practical determination of the hardness of samples obtained as a result of experimental melting, quantitative analysis in ImageJ, systematization of the results in Excel, correlation analysis, construction of a graphical dependence of hardness on the parameters of graphite inclusions. The novelty of the work: practical substantiation of the correlation between hardness and the length of graphite inclusions in oil blanks of piston rings. Research results: it is practically proved that hardness directly depends on the length of graphite inclusions in gray cast iron: as the length of graphite inclusions decreases, hardness increases. At the same time, optimal hardness values are achieved in SCM cast iron with a graphite inclusion length of 45 microns, and in A-XM cast iron with 90-180 microns.