公开(公告)号：US20240287632A1

公开(公告)日：2024-08-29

申请号：US18571637

申请日：2022-06-14

Applicant: JFE STEEL CORPORATION

Inventor： Hidemitsu NEGISHI ,  Takeshi MURAI ,  Keisuke MIZOBATA

IPC: C21C5/52 ,  C21C7/00 ,  C21C7/06 ,  C21C7/068 ,  C21C7/10

CPC classification number: C21C5/5229 ,  C21C7/0006 ,  C21C7/06 ,  C21C7/068 ,  C21C7/10 ,  C21C2300/08

Abstract: A treatment method of molten steel capable of preventing metal components in molten steel from being reoxidized by reacting with oxides in molten slag, inhibiting occurrence of inclusions, and reducing nitrogen in the molten steel. The treatment method of molten steel in which a potential difference is applied between the molten steel and the molten slag by using a direct-current power supply and through two electrodes which are a negative electrode being an electrode in contact with the molten steel and a positive electrode being another electrode in contact with only the molten slag is characterized by including: a deoxidation step of deoxidizing the molten steel by adding a deoxidizing agent to the molten steel; and a step of applying the potential difference after the deoxidation step. Also, a steel production method by which the obtained molten steel is cast after components thereof are adjusted.

公开(公告)号：US20230340629A1

公开(公告)日：2023-10-26

申请号：US18010103

申请日：2021-06-16

Applicant: JFE STEEL CORPORATION

Inventor： Keisuke MIZOBATA ,  Akifumi HARADA ,  Yoshie NAKAI ,  Takeshi MURAI ,  Hidemitsu NEGISHI

IPC: C21C7/10

CPC classification number: C21C7/10

Abstract: A molten steel refining method increases a circulating rate using an RH vacuum degassing apparatus. An immersion depth of an immersion tube into molten steel inside a vacuum tank or a circulating gas flow rate is determined such that a stirring power energy density ε for the molten steel meets the following formulae: ε = [371GT × ln{ 1 + (ρLgH0/P)}]/Wv, Wv = (π·Dv2/4) × H0 × ρL/1000, H0 = hv + L - hG, hv = (P0 - P)/(ρLg) + 1 -L, 1.35 × 105 × DU/WV