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:
Apr. 21, 2025

Filed:

Nov. 10, 2020
Applicant:

Kobe Steel, Ltd., Kobe, JP;

Inventors:

Koji Tokuda, Kobe, JP;

Tsuyoshi Mimura, Kobe, JP;

Assignee:

Kobe Steel, Ltd., Kobe, JP;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C21B 11/10 (2005.12); C21C 1/00 (2005.12);
U.S. Cl.
CPC ...
C21B 11/10 (2012.12); C21C 1/00 (2012.12);
Abstract

A method includes, in a first furnace, melting 40% to 95% by mass of a solid-state direct reduced iron, and separating a molten pig iron having a carbon content of 2.0% to 5.0% by mass and a temperature of 1350 to 1550° C. and a slag having a basicity of 1.0 to 1.4. In a second furnace, a remainder of the solid-state direct reduced iron is melted together with the molten pig iron separated in the first furnace to form a molten material, and oxygen is blown onto the molten material to decarburize into a molten steel. The solid-state direct reduced iron includes 3.0% by mass or more of SiOand AlOin total and 1.0% by mass or more of carbon. A ratio of a metallic iron to a total iron content contained in the solid-state direct reduced iron is 90% by mass or more.


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