Factors affecting boron yield rate for high-strength steel production

• Published in: Materials research innovations Vol. 19; no. sup5; pp. S5-438 - S5-442
• Main Authors: Zang, R. Y., Li, J., Gu, J. B., Shi, C. B., Liu, W. J.
• Format: Journal Article
• Language: English
• Published: Taylor & Francis 01.05.2015
• Subjects: Acid-soluble aluminium; Aluminum; Boron; Boron yield rate; Continuous casting; Dissolved oxygen; Fixing nitrogen; High strength steels; Liquids; Oxidation; Oxygen; Secondary oxidation; Steels
• ISSN: 1432-8917; 1433-075X
• DOI: 10.1179/1432891714Z.0000000001127

Factors affecting boron yield rate in liquid steel during the refining and continuous casting stages were analysed by industrial tests and thermodynamic calculations. The experimental results showed that boron could not react with the dissolved oxygen in the liquid steel above 1794 K because of the low oxygen levels. The inclusions containing boron were caused by secondary oxidation of the liquid steel. During refining and continuous casting stages, boron could not react with nitrogen and N 2 when the actual content of boron in the liquid steel was 16 ppm. The main reason for boron loss is the secondary oxidation of the boron. So, taking effective measures against secondary oxidation of boron is an important method to improve the boron yield rate. The boron yield rate increases with the increase of acid-soluble aluminium in steel. Controlling the appropriate content of acid-soluble aluminium effectively prevents oxidation of the boron. Liquid steel secondary oxidation can be prevented by optimising the refining and Continuous Casting (CC) technology including by enhancing the seal protection of the liquid steel from the tundish to the mould.