公开(公告)号：US20230127243A1

公开(公告)日：2023-04-27

申请号：US17915739

申请日：2021-03-25

Applicant: JFE STEEL CORPORATION

Inventor： Lingling YANG ,  Yoshiyasu KAWASAKI ,  Tatsuya NAKAGAITO ,  Shotaro TERASHIMA ,  Shunsuke YAMAMOTO ,  Katsuya HOSHINO ,  Yuki TAKEDA

IPC: C21D9/46 ,  C22C38/60 ,  C22C38/38 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/10 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C21D6/00 ,  C21D8/02 ,  B32B15/01

Abstract: A steel sheet having a tensile strength (TS) of 1180 MPa or more, high LME resistance, and good weld fatigue properties. The steel sheet has a specific chemical composition and a specific steel microstructure. Crystal grains containing an oxide of Si and/or Mn in a region within 4.9 μm in a thickness direction from a surface of the steel sheet have an average grain size in the range of 3 to 10 μm, the lowest Si concentration LSi and the lowest Mn concentration LMn in the region within 4.9 μm in the thickness direction from the surface of the steel sheet and a Si concentration TSi and a Mn concentration TMn at a quarter thickness position of the steel sheet satisfy a specified formula.

公开(公告)号：US20230082367A1

公开(公告)日：2023-03-16

申请号：US17760362

申请日：2020-11-19

Applicant: JFE STEEL CORPORATION

Inventor： Shunsuke YAMAMOTO ,  Shotaro TERASHIMA ,  Yuki TAKEDA ,  Michitaka SAKURAI ,  Katsuya HOSHINO ,  Yoshiyasu KAWASAKI

IPC: C21D9/46 ,  C22C38/02 ,  C22C38/38 ,  C21D1/26 ,  C22C38/12 ,  C22C38/06 ,  C22C38/00 ,  C22C38/28 ,  C22C38/32 ,  C22C38/16 ,  C21D6/00 ,  C22C38/08 ,  C23C2/02 ,  C23C2/28 ,  C23C2/40

Abstract: To obtain a high-strength hot-dip galvanized steel sheet having excellent surface appearance even in the case where a steel strip containing Mn at a predetermined ratio or more to Si is subjected to hot-dip galvanizing treatment, a method of producing a hot-dip galvanized steel sheet using a continuous hot-dip galvanizing apparatus comprises: subjecting a steel strip to annealing, by conveying it in an annealing furnace; and subjecting the steel strip discharged from a cooling zone to hot-dip galvanizing using a hot-dip galvanizing line, to obtain a hot-dip galvanized steel sheet. The steel strip has a chemical composition containing, in mass %, Mn: 1.7% or more and 3.5% or less and Si: 0.2% or more and 1.05% or less and satisfying [Si]/[Mn]≤0.30. The chemical composition, a dew point of an atmosphere in the soaking zone, and a delivery temperature of the heating zone satisfy Formula (1).

公开(公告)号：US20240229186A1

公开(公告)日：2024-07-11

申请号：US18558192

申请日：2022-02-08

Applicant: JFE STEEL CORPORATION

Inventor： Gentaro TAKEDA ,  Hideyuki TAKAHASHI ,  Yuki TAKEDA

IPC: C21D11/00 ,  C21D1/76 ,  C21D6/00 ,  C21D9/46 ,  C23C2/02 ,  C23C2/06 ,  C23C2/28

CPC classification number: C21D11/00 ,  C21D1/76 ,  C21D6/005 ,  C21D9/46 ,  C23C2/022 ,  C23C2/06 ,  C23C2/28

Abstract: Provided are a dew point control method for a continuous annealing furnace, a continuous annealing method for a steel sheet, a steel sheet manufacturing method, a continuous annealing furnace, a continuous hot-dip galvanizing line, and a galvannealing line by which a furnace dew point can be controlled in a short time. The dew point control method includes stopping or reducing supply of humidified gas into the furnace, and supplying dry gas along a furnace inner wall of the continuous annealing furnace in the continuous annealing furnace. According to the dew point control method, a temperature of the furnace inner wall of the continuous annealing furnace may be at least 30° C. higher than a furnace atmosphere temperature in the continuous annealing furnace.

公开(公告)号：US20230366073A1

公开(公告)日：2023-11-16

申请号：US18031119

申请日：2021-08-25

Applicant: JFE STEEL CORPORATION

Inventor： Hiroaki ONO ,  Yuki TAKEDA ,  Nozomi HISAJIMA ,  Yumiko TAKEI

IPC: C23C2/00 ,  C23C2/06 ,  C23C2/40

CPC classification number: C23C2/526 ,  C23C2/06 ,  C23C2/40

Abstract: A surface temperature measuring method includes: acquiring a radiation light amount of a surface of a measurement object; irradiating the surface of the measurement object with light under a specular reflection condition to acquire a specular reflection light amount; irradiating the surface of the measurement object with light under a diffuse reflection condition to acquire a diffuse reflection light amount; calculating an emissivity of the surface of the measurement object by using a model indicating a relationship between an emissivity and a specular reflectance, and a relationship between the emissivity and a diffuse reflectance of the surface of the measurement object, the acquired specular reflection light amount, and the acquired diffuse reflection light amount; and calculating a surface temperature of the measurement object using the acquired radiation light amount and the calculated emissivity.

公开(公告)号：US20230160032A1

公开(公告)日：2023-05-25

申请号：US17915696

申请日：2021-03-25

Applicant: JFE STEEL CORPORATION

Inventor： Lingling YANG ,  Yoshiyasu KAWASAKI ,  Hidekazu MINAMI ,  Tatsuya NAKAGAITO ,  Shotaro TERASHIMA ,  Shunsuke YAMAMOTO ,  Katsuya HOSHINO ,  Yuki TAKEDA

IPC: C21D9/46 ,  C23C2/40 ,  C23C2/06 ,  C21D8/02 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  B21C47/02

CPC classification number: C21D9/46 ,  C23C2/40 ,  C23C2/06 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0273 ,  C22C38/001 ,  C22C38/002 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  B21C47/02 ,  C21D2211/002 ,  C21D2211/005 ,  C21D2211/008 ,  C21D2211/001

Abstract: A steel sheet having a tensile strength (TS) of 780 MPa or more and less than 1180 MPa, high LME resistance, and good weld fatigue properties. The steel sheet has a specific chemical composition and a specific steel microstructure. Crystal grains containing an oxide of Si and/or Mn in a region within 4.9 μm in a thickness direction from a surface of the steel sheet have an average grain size in the range of 3 to 10 μm, the lowest Si concentration LSi and the lowest Mn concentration LMn in the region within 4.9 μm in the thickness direction from the surface of the steel sheet and a Si concentration TSi and a Mn concentration TMn at a quarter thickness position of the steel sheet satisfy a specified formula.

公开(公告)号：US20230151451A1

公开(公告)日：2023-05-18

申请号：US17915020

申请日：2021-03-25

Applicant: JFE STEEL CORPORATION

Inventor： Yoshiyasu KAWASAKI ,  Lingling YANG ,  Shotaro TERASHIMA ,  Tatsuya NAKAGAITO ,  Shunsuke YAMAMOTO ,  Katsuya HOSHINO ,  Yuki TAKEDA

IPC: C21D9/46 ,  C21D8/02 ,  C21D6/00 ,  C22C38/38 ,  C22C38/60 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/10 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  B32B15/01

CPC classification number: C21D9/46 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0263 ,  C21D6/001 ,  C21D6/002 ,  C21D6/005 ,  C21D6/007 ,  C21D6/008 ,  C22C38/38 ,  C22C38/60 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/10 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/008 ,  C22C38/005 ,  C22C38/002 ,  C22C38/001 ,  B32B15/013 ,  C21D2211/001 ,  C21D2211/005

Abstract: A steel sheet with a tensile strength (TS) of 1180 MPa or more, a member, and a method for producing them. In a region of the steel sheet within 4.9 μm in the thickness direction, a region with a Si concentration not more than one-third of the Si concentration in the chemical composition of the steel sheet and with a Mn concentration not more than one-third of the Mn concentration in the chemical composition of the steel sheet has a thickness of 1.0 μm or more. The lowest Si concentration LSi and the lowest Mn concentration LMn in the region within 4.9 μm in the thickness direction from the surface of the steel sheet and a Si concentration TSi and a Mn concentration TMn at a quarter thickness position of the steel sheet satisfy the following formula (1):


LSi+LMn≤(TSi+TMn)/4  (1).

公开(公告)号：US20230129828A1

公开(公告)日：2023-04-27

申请号：US17914895

申请日：2021-03-25

Applicant: JFE STEEL CORPORATION

Inventor： Yoshiyasu KAWASAKI ,  Lingling YANG ,  Shotaro TERASHIMA ,  Hidekazu MINAMI ,  Tatsuya NAKAGAITO ,  Shunsuke YAMAMOTO ,  Katsuya HOSHINO ,  Yuki TAKEDA

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

Abstract: A steel sheet with a tensile strength (TS) of 780 MPa or more and less than 1180 MPa, a member, and a method for producing them. In a region of the steel sheet within 4.9 μm in the thickness direction, a region with a Si concentration not more than one-third of the Si concentration in the chemical composition of the steel sheet and with a Mn concentration not more than one-third of the Mn concentration in the chemical composition of the steel sheet has a thickness of 1.0 μm or more. The lowest Si concentration LSi and the lowest Mn concentration LMn in the region within 4.9 μm from the surface of the steel sheet and a Si concentration TSi and a Mn concentration TMn at a quarter thickness position of the steel sheet satisfy the following formula (1): LSi+LMn≤(TSi+TMn)/4  (1).