公开(公告)号：US20220282353A1

公开(公告)日：2022-09-08

申请号：US17630243

申请日：2020-07-29

Applicant: JFE Steel Corporation

Inventor： Takuya Hirashima ,  Yu Hashimoto ,  Shinjiro Kaneko ,  Yoshihiko Ono

IPC: C21D9/50 ,  C21D9/46 ,  C21D8/02 ,  C21D6/00 ,  C22C38/54 ,  C22C38/50 ,  C22C38/48 ,  C22C38/46 ,  C22C38/44 ,  C22C38/42 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00

Abstract: The high strength steel sheet of the present invention has a specific chemical composition, and contains, in terms of area fraction relative to an entire steel microstructure, 30% or more and 100% or less ferrite, 0% or more and 70% or less martensite, and less than 20% in total of pearlite, bainite and retained austenite, and the ferrite contains, in terms of area fraction relative to an entire microstructure, 0% or more and 10% or less non-recrystallized ferrite, with a difference of the area fraction of the non-recrystallized ferrite in the longitudinal direction of the steel sheet of 5% or smaller.

公开(公告)号：US20220275469A1

公开(公告)日：2022-09-01

申请号：US17629857

申请日：2020-07-29

Applicant: JFE Steel Corporation

Inventor： Takuya Hirashima ,  Yu Hashimoto ,  Shinjiro Kaneko ,  Yoshihiko Ono

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

Abstract: The high strength steel sheet of the present invention has a specific chemical composition, and contains, in terms of area fraction relative to an entire steel microstructure, 30% or more and 100% or less ferrite, 0% or more and 70% or less martensite, and less than 20% in total of pearlite, bainite and retained austenite, a total content of Nb and Ti contained in a precipitate having a particle size of smaller than 20 nm is 25 mass ppm or more and 220 mass ppm or less, and the difference between the maximum value and the minimum value of the total content of Nb and Ti contained in the precipitate having a particle size of smaller than 20 nm, in the longitudinal direction of the steel sheet, is smaller than 20 mass ppm.