公开(公告)号：US20250163525A1

公开(公告)日：2025-05-22

申请号：US18836352

申请日：2022-12-01

Applicant: JFE STEEL CORPORATION

Inventor： Yoshiko NAKAHARA ,  Koki TERUI ,  Sumito OZAWA

IPC: C21B13/00

Abstract: In a process of reducing iron ore powder by fluidized bed reduction furnaces and a smelting reduction furnace, CO2 emissions are significantly reduced and stable operation is possible regardless of fluctuations in various conditions. A method of reducing iron ore powder, the method including: a fluidized bed reduction process of fluidizing and reducing iron ore powder in a fluidized bed reduction furnace using a first reducing gas to produce partially reduced iron; and a smelting reduction process of reducing the partially reduced iron in a smelting reduction furnace using a second reducing gas. Fluidized bed reduction furnace top gas discharged from the top of the fluidized bed reduction furnace is used for synthesis of methane and reforming of methane-containing gas.

公开(公告)号：US20220177992A1

公开(公告)日：2022-06-09

申请号：US17437357

申请日：2020-02-13

Applicant: JFE STEEL CORPORATION

Inventor： Yoshie OBATA ,  Katsutoshi TAKASHIMA ,  Minoru TANAKA ,  Yoshiko NAKAHARA

IPC: C21D9/46 ,  B21D22/02 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/14 ,  C22C38/12 ,  C22C38/60 ,  C23C2/06 ,  C23C2/12 ,  C23C2/40 ,  C23G1/00 ,  C21D8/02 ,  B21C47/02

Abstract: A hot press member includes excellent indentation peel strength which has a tensile strength of 1780 MPa or more. A plating layer has at a surface thereof a 10-point average roughness Rzjis of 25 μm or less, and a steel sheet contains, in mass %, not less than 0.25% but less than 0.50% of C, 1.5% or less of Si, 1.1-2.4% of Mn, 0.05% or less of P, 0.005% or less of S, 0.01-0.50% of Al, 0.010% or less of N, 0.001-0.020% of Sb, 0.005-0.15% of Nb, and 0.005-0.15% of Ti, the balance being Fe and incidental impurities. The average crystal grain size of prior austenite is 7 μm or less and the volume proportion of martensite is 90% or more, within 50 μm in the thickness direction from the surface of the steel sheet excluding the plating layer.