Morphology and Composition of Inclusions in Si–Mn Deoxidized Steel at the Solid-Liquid Equilibrium Temperature

Morphology and composition of inclusions change with temperature. However, besides the temperature conditions during steelmaking or continuous casting, other factors contributing to changes in the morphology and composition of inclusions during solidification are still unknown. In this study, the fo...

Full description

Bibliographic Details
Main Authors: Gamutan, Jonah, Miki, Takahiro, Nagasaka, Tetsuya
Format: Journal Article
Published: Nippon Tekko Kyokai/Iron and Steel Institute of Japan 2020
Subjects:
Online Access:http://hdl.handle.net/20.500.11937/90248
_version_ 1848765355376246784
author Gamutan, Jonah
Miki, Takahiro
Nagasaka, Tetsuya
author_facet Gamutan, Jonah
Miki, Takahiro
Nagasaka, Tetsuya
author_sort Gamutan, Jonah
building Curtin Institutional Repository
collection Online Access
description Morphology and composition of inclusions change with temperature. However, besides the temperature conditions during steelmaking or continuous casting, other factors contributing to changes in the morphology and composition of inclusions during solidification are still unknown. In this study, the formation of complex inclusions in Si–Mn deoxidized steel after isothermal holding at the solid-liquid equilibrium temperature (TS) was investigated. The typical inclusions found in the alloy were MnO–SiO2 based, spherically shaped and homogeneously distributed. With isothermal holding at the solid-liquid equilibrium temperature, formation of a secondary SiO2-rich inclusion phase occurred. The changes in the composition of the inclusions depended on the manganese and silicon contents in the metal. The general mechanism of inclusion formation observed in this study can be divided into three steps: 1) the formation of primary MnO–SiO2 inclusions above the liquidus temperature when the steel is in a completely molten state as a result of the deoxidation process; 2) the nucleation of secondary inclusions as the molten steel becomes supersaturated with the solute elements while holding at the solid-liquid equilibrium temperature; and 3) the growth and coalescence of inclusions due to natural convection in the molten alloy. From this, the inclusions formed in Si–Mn deoxidized alloys held isothermally at the solid-liquid equilibrium temperature were of three types: primary MnO–SiO2 inclusions, secondary SiO2 inclusions and complex inclusions with both primary MnO–SiO2 inclusions and precipitated secondary SiO2 inclusions.
first_indexed 2025-11-14T11:33:56Z
format Journal Article
id curtin-20.500.11937-90248
institution Curtin University Malaysia
institution_category Local University
last_indexed 2025-11-14T11:33:56Z
publishDate 2020
publisher Nippon Tekko Kyokai/Iron and Steel Institute of Japan
recordtype eprints
repository_type Digital Repository
spelling curtin-20.500.11937-902482023-02-22T07:08:09Z Morphology and Composition of Inclusions in Si–Mn Deoxidized Steel at the Solid-Liquid Equilibrium Temperature Gamutan, Jonah Miki, Takahiro Nagasaka, Tetsuya Si–Mn deoxidation complex inclusion formation solid-liquid equilibrium temperature microsegregation Morphology and composition of inclusions change with temperature. However, besides the temperature conditions during steelmaking or continuous casting, other factors contributing to changes in the morphology and composition of inclusions during solidification are still unknown. In this study, the formation of complex inclusions in Si–Mn deoxidized steel after isothermal holding at the solid-liquid equilibrium temperature (TS) was investigated. The typical inclusions found in the alloy were MnO–SiO2 based, spherically shaped and homogeneously distributed. With isothermal holding at the solid-liquid equilibrium temperature, formation of a secondary SiO2-rich inclusion phase occurred. The changes in the composition of the inclusions depended on the manganese and silicon contents in the metal. The general mechanism of inclusion formation observed in this study can be divided into three steps: 1) the formation of primary MnO–SiO2 inclusions above the liquidus temperature when the steel is in a completely molten state as a result of the deoxidation process; 2) the nucleation of secondary inclusions as the molten steel becomes supersaturated with the solute elements while holding at the solid-liquid equilibrium temperature; and 3) the growth and coalescence of inclusions due to natural convection in the molten alloy. From this, the inclusions formed in Si–Mn deoxidized alloys held isothermally at the solid-liquid equilibrium temperature were of three types: primary MnO–SiO2 inclusions, secondary SiO2 inclusions and complex inclusions with both primary MnO–SiO2 inclusions and precipitated secondary SiO2 inclusions. 2020 Journal Article http://hdl.handle.net/20.500.11937/90248 10.2355/isijinternational.ISIJINT-2019-313 http://creativecommons.org/licenses/by-nc-nd/4.0/ Nippon Tekko Kyokai/Iron and Steel Institute of Japan fulltext
spellingShingle Si–Mn deoxidation
complex inclusion formation
solid-liquid equilibrium temperature
microsegregation
Gamutan, Jonah
Miki, Takahiro
Nagasaka, Tetsuya
Morphology and Composition of Inclusions in Si–Mn Deoxidized Steel at the Solid-Liquid Equilibrium Temperature
title Morphology and Composition of Inclusions in Si–Mn Deoxidized Steel at the Solid-Liquid Equilibrium Temperature
title_full Morphology and Composition of Inclusions in Si–Mn Deoxidized Steel at the Solid-Liquid Equilibrium Temperature
title_fullStr Morphology and Composition of Inclusions in Si–Mn Deoxidized Steel at the Solid-Liquid Equilibrium Temperature
title_full_unstemmed Morphology and Composition of Inclusions in Si–Mn Deoxidized Steel at the Solid-Liquid Equilibrium Temperature
title_short Morphology and Composition of Inclusions in Si–Mn Deoxidized Steel at the Solid-Liquid Equilibrium Temperature
title_sort morphology and composition of inclusions in si–mn deoxidized steel at the solid-liquid equilibrium temperature
topic Si–Mn deoxidation
complex inclusion formation
solid-liquid equilibrium temperature
microsegregation
url http://hdl.handle.net/20.500.11937/90248