Study of the effect of carbon on the fractal dimension of steel

As a result of the formation of the steel structure in open systems, their elements often have a complex geometric configuration. From these positions, the approximation of structural components by Euclidean figures introduces an error in their analysis. Carbon is one of the main components of the chemical composition of steels, significantly affects their structure and performance characteristics. It is proposed to study the effect of carbon on the fractal dimension of steel. Materials and methodology. As the materials for the study, Cт3пс, 20, 40, and У8 steels were chosen. Steel had a ferrite-pearlite structure. The chemical composition of steels has changed within the existing industry standard (ГОСТ). The fractal dimension of the ferrite-pearlite structure was determined using the developed method based on the convergence of the cellular and point dimensions. The results of the experiment. Dependencies are obtained that describe the relationship between the carbon content in the range 0,14…0,84 % and the fractal dimension of perlite, ferrite and their grain boundaries. These dependencies have an exponential form due to an increase in the perlite content to the limiting values that is observed in eutectoid steels. The pair correlation coefficients of the obtained exponential models vary within 0,75…0,80, which confirms the influence of the perlite content in steel on its fractal dimension. A comparative analysis of the fractal dimensions of the ferrite-pearlite structure with hardness indices of HB steels after annealing according to standard production technology indicates the existence of sensitivity between these indices. Conclusions. The influence of carbon on the ferrite-pearlite structure of the hypereutectoid and eutectoid steel, which is fixed using the fractal dimension, is studied. The results can be used to study the effect of carbon on the geometric shape of perlite, ferrite and grain boundaries.