Evolution of Mgo·Al₂O₃ Based Inclusions in Alloy Steel During the Refining Process  Full text

Shufeng Yang^1,2, Jingshe Li¹, Lifeng Zhang², Kent Peaslee², Zaifei Wang¹

¹School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing,
Beijing 100083, China
²Department of Materials Science and Engineering, Missouri University of Science and Technology,
Rolla, MO 65401, USA

Metall. Min. Ind.,  2010, Vol. 2, No. 2, pp. 87-92

Abstract

The transformation of MgO·Al₂O₃ based inclusions in alloy steel during refining has been studied by industrial trials. Besides Factsage software is applied to study the formation and modification of spinel inclusions in alloy steel using calcium treatment during refining process. The results show the transformation sequence of inclusions is: MgO·Al₂O₃ → CaO–Al2O3–MgO complex inclusions → MgO·Al₂O₃, and under present experimental condition, in order to avoid forming MgOAl2O3 inclusions the content of dissolved Ca in the molten steel has to reach 1ppm. Also the results show that when more calcium was added into molten steel, the content of Al₂O₃ and MgO will be lower. Besides, increases the content of CaO in the inclusions will increase even if the content of SiO₂ changes little.

Keywords: ALLOY STEEL, NON-METALLIC INCLUSIONS, MGO·Al₂O₃ SPINEL, THERMODYNAMICS