Heat treatment and characterization of high manganese steels with different boron content

In this study, high manganese steel samples with different boron-doped (boron additives of 11ppm, 53 ppm, and 374 ppm) were heat treated at different temperatures after cutting. The effects of applied heat treatment temperatures on the microstructural and mechanical properties of the samples were investigated. Different boron-doped high-manganese steel samples were produced by casting in an open-air environment. The samples were heat treated at 900, 1000 and 1100oC. Microstructure examinations were carried out by optical microscope and scanning electron microscope (SEM) analysis of the samples with and without heat treatment, and the presence of dendritic cementite precipitates at the grain boundaries was determined. It was understood that the carbides changed from a dendritic structure to a spherical form with the increased heat treatment temperature. According to the data obtained by X-ray diffractometry analysis (XRD), it was understood that the östenitik phase structure transformed into  martenzit and  martenzit phase structures in heat-treated and without heat-treated samples. It is seen that the data obtained from SEM analysis, EDS analysis, optical microscope analysis, and XRD analysis are consistent with each other. The yellow diagonal structure seen in the images obtained by optical microscope analysis was determined to be TiN precipitate as a result of EDS analysis. The black precipitates seen in the microstructure images obtained from SEM analysis are thought to be AlN precipitates by EDS analysis. By measuring the hardness values of the heat-treated and untreated samples, the changes in the mechanical properties of boron-doped different high manganese steels depending on the heat treatment temperatures were seen. However, it was determined that there was no significant change in the hardness of the samples depending on the heat treatment temperatures applied to the samples. The obtained results were discussed by comparing with the literature.