Use of complex modifiers for improvement of steel R7 quality
Authors: J. Tatarko, M. Kushnir, I. Markova, T. Ivchenko
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Purpose. Stabilizing of chemical composition and properties, decrease of detrimental impurities concentrations, amount of nonmetallics, grinding down of grain of the R7 wheeled steel by treatment of multicomponent modifiers. Methodology. Probed chemical composition and mechanical properties in accordance with UIC 812-3 and EN 13262 serial melting steel R7 and treated a multicomponent deoxidizers-modifiers are researched. Processing of data is conducted by a regressive-cross-correlation analysis. Findings. Influence of operations of out-of-furnace treatment is set on detrimental impurities concentration. Using of complex modifiers has reduced the concentration of sulfur most effectively. It is shown that in the modified melting variation of both basic alloying elements and admixtures has decreased, homogeneity and dispersion of structure have increased, what mechanical properties of wheels were stabilized due to. Originality. Influence was first set each of the stages of out-of-furnace treatment steel R7 on the detrimental impurities concentration, micro hardness, structure of hard-tempered tests. Dependences of mechanical characteristics were got of the detrimental impurities concentrations. Practical value. By treatment of multicomponent deoxidizers-modifiers, stabilization of chemical composition, sulfur concentration reducing, nonmetallic inclusions amount, grain refining and improving the homogeneity of the structure are achieved, this led to stabilizing and increase of mechanical properties level. It is shown the efficiency of multicomponent deoxidizers-modifiers usage in order to improve quality of steel R7 and reliability of wheels made of it.