Original Article

Evolution of inclusions in Si-Al deoxidized 4Cr13 stainless steels

¹ Chengdu Advanced Metal Material Industry Technology Research Institute, Co.,Ltd., 610000, Chengdu, PR China
² Ansteel Beijing Research Institute Co., Ltd, 102211, Beijing, PR China
³ Changcheng Jiangyou Special Steel Co., Ltd., 621700, Mianyang, PR China

^* e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Received: 6 April 2026
Accepted: 22 June 2026

Abstract

To reduce Type B inclusions in 4Cr13 stainless steel produced via the AOD–LF–VD–ingot casting route, this study investigated inclusion evolution under different deoxidation conditions during AOD secondary reduction. The results show that Si deoxidation effectively lowers the final Al content and suppresses Type B inclusions; however, excessive Si addition is detrimental. When the Si addition was 2 kg/t, the increased SiO₂ content reduced slag basicity to about 2.2, weakening the slag’s ability to absorb Al₂O₃-rich and spinel inclusions. The very low final Al content also promoted the formation of low-melting-point Si-rich inclusions during solidification, contributing to Type C inclusions. Increasing slag basicity to approximately 3.3 or higher enhanced spinel removal, but excessive Al still promoted Al₂O₃-rich and MgO·Al₂O₃ spinel formation. The optimal Si addition was 1.5 kg/t, at which slag basicity and Al content were well balanced, enabling effective inclusion absorption, and the inclusions formed during cooling and solidification were finely dispersed.