The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 20, 2026
Filed:
Jun. 16, 2021
Jfe Steel Corporation, Tokyo, JP;
Keisuke Mizobata, Tokyo, JP;
Akifumi Harada, Tokyo, JP;
Yoshie Nakai, Tokyo, JP;
Takeshi Murai, Tokyo, JP;
Hidemitsu Negishi, Tokyo, JP;
JFE STEEL CORPORATION, Tokyo, JP;
Abstract
A molten steel refining method that increases a circulating rate using an RH vacuum degassing apparatus is provided. An immersion depthof an immersion tube into molten steel inside a vacuum tank or a circulating gas flow rate G is determined such that a stirring power energy density ε for the molten steel meets the following formulae. (Symbols in the formulae represent the following. G: the circulating gas flow rate, T: a temperature of the molten steel, ρ: a density of the molten steel, g: a gravitational acceleration, H: a height from a position of a circulating gas blow-in nozzle to a bath surface of the molten metal inside the vacuum tank in a stationary state, P: a pressure inside the vacuum tank, P: an atmospheric pressure, h: a height from the bath surface of the molten steel inside the vacuum tank in the stationary state to a bed, L: a height from a lower end of the immersion tube to the bed, h: a height from the lower end of the immersion tube to the position of the circulating gas blow-in nozzle, l: the immersion depth of the immersion tube into the molten steel, and D: an inside diameter of a rising tube.) ε=[371GT×ln{1+(ρgH/P)}]/W, W=(π·D/4)×H×ρ/1000, H=h+L−h, h=(P−P)/(ρg)+1−L, 1.35×10×D/W<ε<2.1×10.