Investigation of Inclusion Formation in Light‐Weight Fe–Mn–Al Steels using Automated Scanning Electron Microscope Equipped with Energy‐Dispersive X‐Ray Spectroscopy

Abstract

Herein, the effect of Mn content on the characteristics and the formation of inclusions in light‐weight Fe–Mn–Al steels is investigated. Three laboratory‐produced steels, containing different manganese contents (2%, 5%, and 20%) are investigated. 2D and 3D inclusion characterization methods are used to establish inclusion classification rules for oxide, sulfide, and nitride inclusions using an automated scanning electron microscope (SEM) equipped with energy‐dispersive X‐ray spectroscopy (EDS) (ASPEX system). The observed inclusions are classified into Al2O3(pure), Al2O3–MnS, AlN(pure), AlN–MnS, AlON–MnS, AlON, and MnS. The results show that an increased Mn content of steel increases the number of inclusions, especially Al2O3–MnS and AlN–MnS inclusions. In the case of Al2O3–MnS inclusions, Al2O3 inclusions serve as the site for precipitation of MnS. Thermodynamic calculations suggest that the AlN‐containing inclusions formed during cooling and solidification of steels. Moreover, the formation of AlN–MnS inclusions can take place by the nucleation of MnS on AlN inclusions and vice versa.