Fractal parameterization of the inclusion distribution density in the welded joint metal structure

Abstract

One of the modern proposed methods actively used for diagnosing metal structures is the method of fractal analysis. This method seeks to find the conjunction between the fractal dimension of individual components of the metal structure and its mechanical properties. The comprehensive use of microanalysis and fractal analysis allows not only for comparing structural characteristics but also for finding a numerical parameterization of the elements of this structure. The problem of advance the mechanical properties of welded joints in metal structures remains relevant due to the constant increase in high-strength low-alloy steels used in welded structures. As known, the mechanical properties of welded joints are determined by their structural components, including non-metallic inclusions. A purely qualitative assessment based on the DSTU 8966:2019 standard does not provide an opportunity for a thorough analysis of such an important characteristic as the distribution of inclusions by size and the character of their distribution in the metal matrix. Existing knowledge is based on the peculiarities of the influence of non-metallic inclusions on the mechanical properties of steel welded joints, which requires constant expansion and deepening cognitions, as this work aims to do. The method of fractal analysis allows considering non-metallic inclusions as voids in the metal matrix, which enables parameterization of the inclusion characteristics in the metal structure. The paper describes a methodology that takes into account the distance between inclusions as well as the size of inclusions, which differently affect the mechanical characteristics of the samples. In particular, this article is a continuation of the work [1], which describes an approach to finding relationships between fractal dimensions and mechanical properties. This work focuses on the impact of proposed inoculants on mechanical properties through the distribution of inclusions throughout the metal sample. Keywords: fractal, inclusion, microstructure, inoculants, distribution