Original Article

Effect of Mg treatment on TiN inclusions in interstitial-free steel

Center for Advanced Solidification Technology (CAST) of School of Materials Science and Engineering Shanghai University, & State Key Laboratory of Advanced Special Steel, Shanghai 200444, PR China

* e-mail: fujianxun@shu.edu.cn

Received: 18 August 2024
Accepted: 18 December 2024

Abstract

This article studied the effect of Mg content on TiN inclusions in interstitial-free (IF) steel through laboratory experiments and thermodynamic calculations. In the absence of Mg in the steel, TiN inclusions precipitate with Al₂O₃ of large size and small quantity as the nucleation core, leading to the formation of large and numerous clustered TiN inclusions in the steel. The addition of Mg to the steel provides abundant fine dispersed MgAl₂O₄ and MgO heterogeneous nucleation cores, promoting the nucleation of TiN inclusions. This can effectively reduce the average size of TiN inclusions and improve the clustering phenomenon of TiN in IF steel. In actual industrial production, it is recommended to add 15~20 ppm of Mg to refine TiN inclusions in IF steel.