Analysis of the evolution law of oxide inclusions in U75V heavy rail steel during the LF–RH refining process

• Published in: High temperature materials and processes Vol. 42; no. 1; pp. pp. 7 - 11
• Main Authors: Liu, Hongbo, Xie, Rongyuan, Li, Min, Zhang, Caidong, Yao, Hongyong, Tian, Zhiqiang, Yang, Haibin, Liu, Zhanli, Wang, Qiang, Kang, Ju
• Format: Journal Article
• Language: English
• Published: Berlin De Gruyter 01.01.2023; Walter de Gruyter GmbH
• Subjects: Aluminum oxide; Calcium oxide; Composition; evolution law; Ferroalloys; Field emission microscopy; Inclusion automatic scanning; Ladle metallurgy; LF → RH refining process; Magnesium oxide; Manganese oxides; Melt temperature; Nonmetallic inclusions; oxide inclusions; Rail steels; Silicon dioxide; U75V heavy rail steel
• ISSN: 2191-0324; 0334-6455; 2191-0324
• DOI: 10.1515/htmp-2022-0257

The number density, size and composition of inclusions in U75V heavy rail steel during ladle furnace (LF)–RH refining process were studied by an Aztec-Feature inclusion automatic software which equipped with a field emission microscope. The results showed that the MnO–SiO –Al -type inclusions were the main inclusions at LF start. The MnO–SiO –Al -type inclusions were transformed into the CaO–SiO –Al -type inclusions during the LF refining process because of the Ca and Al elements which were brought by ferroalloy. At the RH start stage, the main inclusions were CaO–SiO –Al -type inclusions with low melting temperature and CaO–MgO–Al -type inclusions with high melting temperature in the sample. And, the CaO–MgO–Al -type inclusions were obviously removed during RH vacuum treatment. The average compositions of CaO–SiO –Al -type inclusions had no obvious change from RH vacuum holding for 15 min, RH vacuum break to RH soft blowing.