Identification of reasons for non-compliance of mechanical properties in boron-containing steel parts

Abstract

Fasteners are widely used as machine parts, structures and mechanisms. Medium-carbon alloy steels and boron-containing alloy steels are used as materials in production. Boron-containing steels have a good combination of strength and plastic properties, as well as a high level of hardenability. This article describes the research work carried out in the laboratory, and considers the reasons for obtaining low values of physical and mechanical parameters of parts manufactured at competitive enterprises. The qualitative characteristics of the metal are determined. The results of chemical, physical-mechanical and metallographic tests, as well as the results of the chemical composition of non-metallic inclusions are presented. The reasons for the discrepancy of mechanical properties in boron-containing steels are considered. The dependence of the introduction of chemical elements into steel: nitrogen, titanium, aluminum is determined. The possibility of evaluating the content of “effective boron” at OJSC “BSW” – the Management Company of the Holding “BMC” is described. The mathematical model used at OJSC “Oskol electrometallurgical combine”, which allows to carry out a theoretical calculation of the value of “effective” boron, is described. Recommendations for improving the technological process of smelting boron-containing steels are given.