Bending fatigue strength of steel with impurities range over 2 μm

The parameters of high-grade steel are influenced by a combination of factors, including chemical composition and production technology. The impurity content is also a key determinant of the quality of high-grade steel. Non-metallic inclusions are one of the factors that influence the properties in particular fatigue strength of steel. The experimental material consisted of semi-finished products of medium-carbon structural steel. The production process involved three melting technologies: steel melting in a basic arc furnace with desulfurization or desulfurization and argon refining and in a oxygen converter and the next subjected to vacuum circulation degassing. This paper discusses the results of microstructural analyses, the changes in bending fatigue strength of steel hardened and tempered at different temperatures subjected to the size proportions and distances between the impurities of structural steel.