公开(公告)号：US20200032364A1

公开(公告)日：2020-01-30

申请号：US16484563

申请日：2017-04-19

Applicant: JFE Steel Corporation

Inventor： Takuya Hirashima ,  Tatsuya Nakagaito ,  Masaki Koba ,  Tatsuya Ehashi ,  Makoto Imamura

IPC: C21D9/46 ,  C22C38/54 ,  C22C38/50 ,  C22C38/48 ,  C22C38/44 ,  C22C38/42 ,  C22C38/06 ,  C22C38/58 ,  C22C38/02 ,  C22C38/00 ,  C21D8/02 ,  C21D6/00 ,  B32B15/01

Abstract: Provided are a high-strength galvanized steel sheet having excellent delayed fracture resistance by reducing the diffusible hydrogen content in the steel and a method for producing the same.The high-strength galvanized steel sheet includes a steel sheet having a prescribed composition and a microstructure including martensite and tempered martensite, the total area fraction of the martensite and the tempered martensite being 30% or more, and a galvanizing layer formed on the surface of the steel sheet. The diffusible hydrogen content in the high-strength galvanized steel sheet is 0.50 wt. ppm or less. The half-width of the hydrogen release peak of the high-strength galvanized steel sheet is 70° C. or less. The diffusible hydrogen content and the half-width of the hydrogen release peak are determined by a prescribed analysis method.

公开(公告)号：US11180823B2

公开(公告)日：2021-11-23

申请号：US16484563

申请日：2017-04-19

Applicant: JFE Steel Corporation

Inventor： Takuya Hirashima ,  Tatsuya Nakagaito ,  Masaki Koba ,  Tatsuya Ehashi ,  Makoto Imamura

IPC: C21D6/00 ,  C21D9/46 ,  C21D8/02 ,  C22C38/54 ,  C22C38/50 ,  C22C38/48 ,  C22C38/44 ,  C22C38/42 ,  C22C38/06 ,  C22C38/58 ,  C22C38/02 ,  C22C38/00 ,  B32B15/01 ,  C23C2/04 ,  C23C2/40 ,  C23C2/28 ,  C25D7/06 ,  C25D5/50 ,  C23C2/06 ,  C22C38/12 ,  C22C38/14 ,  C22C38/18 ,  C22C38/22 ,  C22C38/20 ,  C22C38/04 ,  C22C38/60 ,  C23C28/02 ,  C22C38/32 ,  C22C38/08 ,  B32B15/18 ,  C22C38/24 ,  C23C30/00 ,  C22C38/26 ,  C22C38/40 ,  C22C38/16 ,  C22C38/38 ,  C22C38/46 ,  C22C38/28 ,  B32B15/04 ,  C25D3/56

Abstract: Provided are a high-strength galvanized steel sheet having excellent delayed fracture resistance by reducing the diffusible hydrogen content in the steel and a method for producing the same. The high-strength galvanized steel sheet includes a steel sheet having a prescribed composition and a microstructure including martensite and tempered martensite, the total area fraction of the martensite and the tempered martensite being 30% or more, and a galvanizing layer formed on the surface of the steel sheet. The diffusible hydrogen content in the high-strength galvanized steel sheet is 0.50 wt. ppm or less. The half-width of the hydrogen release peak of the high-strength galvanized steel sheet is 70° C. or less. The diffusible hydrogen content and the half-width of the hydrogen release peak are determined by a prescribed analysis method.

公开(公告)号：US20240318290A1

公开(公告)日：2024-09-26

申请号：US18577328

申请日：2022-06-09

Applicant: JFE Steel Corporation

Inventor： Gentaro Takeda ,  Hideyuki Takahashi ,  Mai Aoyama ,  Maiko Watanabe ,  Tatsuya Ehashi

IPC: C23C2/02 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C23C2/00 ,  C23C2/28 ,  C23C2/40

CPC classification number: C23C2/0224 ,  C22C38/002 ,  C22C38/02 ,  C22C38/04 ,  C23C2/004 ,  C23C2/285 ,  C23C2/40

Abstract: When a hot-dip galvanizing treatment is performed on a steel sheet containing Si in an amount of 0.2 mass % or more by using a continuous hot-dip galvanizing apparatus including an annealing furnace in which a heating zone, a soaking zone, and a cooling zone are arranged in this order, a snout adjacent to the cooling zone, and hot-dip galvanizing equipment, a humidified nitrogen-hydrogen gas mixture containing moisture in such a manner that a certain expression is satisfied is supplied into a region on the downstream side of the soaking zone, gas nozzles are arranged over the entire perimeter of an inner wall of the snout, nitrogen gas or a nitrogen-hydrogen gas mixture is supplied through the gas nozzles downward along the inner wall, and the dew point in the snout is controlled to be −50° C. to −35° C.