Original Article

Transformation of inclusions in S32101 duplex stainless steel during continuous casting

¹ State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 10083, China
² Hongxing Iron & Steel Co. Ltd., Jiuquan Iron and Steel Group Corporation, Jiayuguan 735100, China
³ School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China

^* e-mail: chenxingrun850204@126.com

Received: 8 February 2023
Accepted: 12 December 2023

Abstract

In this study, the formation and characteristics of inclusions in S32101 duplex stainless steel (DSS) during continuous casting were investigated by analyzing inclusions in the tundish and continuous casting slabs. The composition of inclusions changed significantly during the continuous casting. The inclusion type in the tundish was primarily CaO-SiO₂-Al₂O₃-MgO-MnO. There are two types of inclusions in the continuous casting slab: CaO-SiO₂-Al₂O₃-MgO-MnO inclusions with dense Al₂O₃ and MnO, and Al₂O₃-MnO inclusions. TiN wraps the outer layers of both types of inclusions. The results obtained from thermodynamic calculations agreed with the experimental results. The weight percentage of Al₂O₃ and MnO in the inclusions increases significantly with the solidification process. In addition, the Al₂O₃-MnO inclusions were formed in the slab. TiN precipitates during the solidification of the S32101 DSS. The CaO-SiO₂-Al₂O₃-MgO-MnO and Al₂O₃-MnO inclusions can be used as the nucleation sites of TiN.