CALCULATION OF MATERIAL QUALITY CRITERIA USING FRACTAL THEORY

Abstract

Problem statement. Changing the parameters of standard technology can significantly change the properties of rolled iron in a wide range of values. Regulatory and technical industry documentation regulates only the hardness indicators of cast iron rolls, and the requirements for mechanical characteristics and wear resistance are not indicated due to the influence of many technological parameters. Therefore, an important aspect is the prediction for quality indicators of cast iron due to the use of mathematical modeling, in particular the theory of fractals. Materials and methods. Cast iron rolls with a pearlite matrix were studied. The mechanical properties of the working area for cast-iron graded rolled rolls produced by OJSC “Dniprovskyi zavod protnykhnykh valkov”, Dnipro, were determined on standard equipment using INSTRON and CD-40 machines, PSV 5 pendular digger, Shore hardness tester. The microstructure of the rolls was analyzed at a magnification of 200 times. The results of the experiment. As a result of the experiment, it was established that the best among analyzed sensitivity of mechanical properties to dimensional characteristics of carbides is observed for fractal, information and correlation dimensions. Therefore, it is advisable to use these dimensional estimates of carbides in the future to predict the mechanical properties of the working zone for rolled iron with lamellar graphite. To predict the mechanical properties of rolled cast iron with lamellar graphite, it is advisable to use dimensional estimates of graphite and carbides with an increase in the structure of ´200. Conclusions. The analysis of the obtained results showed the promise of using the theory of multifractals for the quantitative assessment of the structural elements of rolled cast iron rolls with a complex geometric shape. This approach makes it possible to use statistical estimates of the dimensions of graphite and carbides to predict and correct the quality indicators of roll metal according to the obtained equations (3-6) along with traditional methods of quantitative metallography, which evaluate their geometric characteristics: shape, distribution, dimensions (length, diameter) and content.