Impacts of Modification of Alloying Method on Inclusion Evolution in RH Refining of Silicon Steel

Fangjie Li; Huigai Li; Shaobo Zheng; Jinglin You; Ke Han; Qijie Zhai

doi:10.3390/ma10101206

Impacts of Modification of Alloying Method on Inclusion Evolution in RH Refining of Silicon Steel

Materials (Basel). 2017 Oct 19;10(10):1206. doi: 10.3390/ma10101206.

Authors

Fangjie Li¹, Huigai Li², Shaobo Zheng³, Jinglin You⁴, Ke Han⁵, Qijie Zhai⁶

Affiliations

¹ State Key Laboratory of Advanced Special Steel, Shanghai Key Laboratory of Advanced Ferrometallurgy, School of Materials Science and Engineering, Shanghai University, Shanghai 200072, China. fangjieli119@126.com.
² State Key Laboratory of Advanced Special Steel, Shanghai Key Laboratory of Advanced Ferrometallurgy, School of Materials Science and Engineering, Shanghai University, Shanghai 200072, China. lihuigai@shu.edu.cn.
³ State Key Laboratory of Advanced Special Steel, Shanghai Key Laboratory of Advanced Ferrometallurgy, School of Materials Science and Engineering, Shanghai University, Shanghai 200072, China. sbzheng@staff.shu.edu.cn.
⁴ State Key Laboratory of Advanced Special Steel, Shanghai Key Laboratory of Advanced Ferrometallurgy, School of Materials Science and Engineering, Shanghai University, Shanghai 200072, China. jlyou@163.com.
⁵ National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA. han@magnet.fsu.edu.
⁶ State Key Laboratory of Advanced Special Steel, Shanghai Key Laboratory of Advanced Ferrometallurgy, School of Materials Science and Engineering, Shanghai University, Shanghai 200072, China. qjzhai@shu.edu.cn.

Abstract

This study explores the effect of introducing additional alloy elements not only in a different order but also at different stages of the Ruhrstahl-Heraeus (RH) process of low-carbon silicon steel production. A more economical method, described as "pre-alloying", has been introduced. The evolution of MnO-FeO inclusions produced by pre-alloying was investigated. Results show that spherical 3FeO·MnO inclusions form first, then shelled FeO·zMnO (z = 0.7-4) inclusions nucleate on the surface of pre-existing 3FeO·MnO. Spherical FeO·zMnO (z = 3-5) is further evolved from shelled 3FeO·MnO by diffusion. Because these MnO-FeO inclusions float up into the slag before degassing, the pre-alloying process does not affect the quality of the melt in the end. Both carbon content and inclusion size conform to industry standards.

Keywords: RH refining; evolution; inclusions; silicon steel.