Fractals Theory Application for Evaluation of Influence of Non Metallic inclusions on Mechanical Properties of S355J2 Steel

Abstract

Abstract Influence of non-metallic inclusions in constructional S355J2 steel on mechanical properties has been evaluated by using fractal theory. Since point evaluation of non-metallic inclusions is fault tolerant to mechanical properties change. Point evaluation of experimental steel grades has been evaluated by 1-2 points. Correlation between mechanical properties of the steel (KV20, σ0.2, σB, δ) and fractal dimensions of non-metallic inclusions has been found. Mechanical properties of the steel have been ranking according to influence of fractal dimensions of non-metallic inclusions on the properties. It has been revealed that non-metallic inclusions, evaluated by their fractal dimensions, have strong effect on impact toughness of the steel S355J2 (R² = 0.89). It can be explained by reducing the metal matrix resistance to crack propagation due to non-metallic inclusions in the matrix. Method of mechanical properties ranging by non-metallic inclusions fractal dimensions allow to vary chemical composition of steel for main parameter obtaining. In this particular case for necessary impact toughness of constructional S355 steel narrower chemical composition of the steel should be chosen.