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.

Date of Patent:
Dec. 30, 2025

Filed:

Feb. 02, 2021
Applicant:

Jfe Steel Corporation, Tokyo, JP;

Inventors:

Shuji Kuyama, Tokyo, JP;

Tomoyoshi Ogasahara, Tokyo, JP;

Yoshie Nakai, Tokyo, JP;

Keisuke Mizobata, Tokyo, JP;

Tomoharu Ishida, Tokyo, JP;

Masamichi Kikuchi, Tokyo, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C21C 7/06 (2006.01); C21C 7/068 (2006.01); C21C 7/072 (2006.01); C21C 7/10 (2006.01); F27D 7/06 (2006.01); G01N 33/2025 (2019.01);
U.S. Cl.
CPC ...
C21C 7/068 (2013.01); C21C 7/072 (2013.01); C21C 7/10 (2013.01); F27D 7/06 (2013.01); G01N 33/2025 (2019.01); F27D 2007/066 (2013.01);
Abstract

A decarburization end point determination method includes: estimating the carbon concentration and oxygen concentration of the molten steel and carbon dioxide gas concentration of exhaust gas in the vacuum chamber by using measurement values of the carbon concentration and the oxygen concentration of the molten steel, a measurement value of internal pressure of the vacuum chamber, and a model formula; correcting a parameter included in the model formula to reduce at least one of a difference between an estimate value and a measurement value of the oxygen concentration and a difference between an estimate value and a measurement value of the carbon dioxide gas concentration of the exhaust gas; estimating the carbon concentration of the molten steel by using the model formula in which the parameter is corrected; and determining timing when an estimate value reaches a target value as the completion time point of the vacuum decarburization treatment.


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