公开(公告)号：US20250101553A1

公开(公告)日：2025-03-27

申请号：US18728338

申请日：2023-01-27

Applicant: NIPPON STEEL CORPORATION

Inventor： Hideto HIROSHIMA ,  Hiroshi SHUTO ,  Kazumasa TSUTSUI ,  Yukiko KOBAYASHI

IPC: C22C38/04 ,  C22C38/00 ,  C22C38/02 ,  C22C38/06 ,  C22C38/12 ,  C22C38/14

Abstract: This hot-rolled steel sheet has a desired chemical composition and microstructure, an average sphere equivalent radius of alloy carbides in the ferrite is 0.5 nm or more and less than 5.0 nm, an average number density of the alloy carbides in the ferrite is 3.5×1016/cm3 or more, an E value that indicates periodicity of the microstructure is 10.7 or more, and an I value that indicates uniformity of the microstructure is 1.020 or more, a standard deviation of a Mn concentration is 0.60 mass % or less, and a tensile strength is 980 MPa or more.

公开(公告)号：US20230416859A1

公开(公告)日：2023-12-28

申请号：US18031104

申请日：2021-11-18

Applicant: NIPPON STEEL CORPORATION

Inventor： Hideto HIROSHIMA ,  Takashi YASUTOMI ,  Eisaku SAKURADA

IPC: C21D9/46 ,  C22C38/38 ,  C22C38/32 ,  C22C38/28 ,  C22C38/26 ,  C22C38/24 ,  C22C38/22 ,  C22C38/14 ,  C22C38/12 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C21D8/02 ,  C21D6/00 ,  C21D1/18

CPC classification number: C21D9/46 ,  C21D2211/001 ,  C22C38/32 ,  C22C38/28 ,  C22C38/26 ,  C22C38/24 ,  C22C38/22 ,  C22C38/14 ,  C22C38/12 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/002 ,  C22C38/001 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0263 ,  C21D6/002 ,  C21D6/005 ,  C21D6/008 ,  C21D1/18 ,  C21D2211/002 ,  C21D2211/005 ,  C21D2211/008 ,  C21D2211/009 ,  C22C38/38

Abstract: This steel sheet has a predetermined chemical composition, has a microstructure in which a number density of alloy carbides present at grain boundaries and having a major axis of 10 to 100 nm is 1.0×108 to 1.0×1011/cm2 and a number density of alloy carbides present in grains and having a major axis of 10 nm or less is 1.0×1016 to 1.0×1019/cm3, and has a tensile strength of 1,030 MPa or more.