公开(公告)号：US20250108422A1

公开(公告)日：2025-04-03

申请号：US18726221

申请日：2022-11-17

Applicant: JFE STEEL CORPORATION

Inventor： Rinta SATO ,  Kazuhiko YAMAZAKI ,  Yoichi MAKIMIZU ,  Minoru TANAKA

IPC: B21D22/02 ,  C22C21/02 ,  C23C2/12 ,  C23C2/40

Abstract: A steel sheet for hot press forming that can reduce diffusible hydrogen content introduced in hot press forming without controlling the atmosphere dew point, and may be used to obtain a hot pressed member that has excellent post-coating corrosion resistance. The steel sheet includes a base steel sheet and a coated layer on both sides of the base steel sheet. The coated layer has a chemical composition containing Si: 7 mass % to 11 mass %, Mg: 0.6 mass % to 1.9 mass %, one or both of Ca and Sr: in total, 1.0% to 10% of Mg, and Fe: 0 mass % to 30 mass %, with the balance being Al and inevitable impurity. Concentration of Mg solute in Al phase in the coated layer is less than 1 mass %, and average thickness of the coated layer is 10 μm to 30 μm on each side of the base steel sheet.

公开(公告)号：US20240263287A1

公开(公告)日：2024-08-08

申请号：US18565655

申请日：2022-03-16

Applicant: JFE STEEL CORPORATION

Inventor： Hidekazu MINAMI ,  Yusuke WADA ,  Yuki TOJI ,  Yoichi MAKIMIZU

IPC: C22C38/04 ,  C21D6/00 ,  C21D8/02 ,  C21D9/46 ,  C22C38/02 ,  C22C38/06 ,  C23C2/02 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40

CPC classification number: C22C38/04 ,  C21D6/005 ,  C21D8/0226 ,  C21D8/0263 ,  C21D8/0268 ,  C21D8/0273 ,  C21D9/46 ,  C22C38/02 ,  C22C38/06 ,  C23C2/024 ,  C23C2/06 ,  C23C2/29 ,  C23C2/40

Abstract: Provided is a hot-dip galvanized steel sheet that has a high YR, as well as high ductility, stretch flangeability, and bendability, improved shear workability, and a TS of 1,180 MPa or more. The base steel sheet of the hot-dip galvanized steel sheet has a defined chemical composition and steel microstructure. In particular, a number ratio of retained austenite (y) having an aspect ratio of 2.0 or less is more than 50%, a number of bins of hardness frequency: 0.25 or more is 1, the area ratio of quenched martensite in a surface layer is 80% or less, a surface layer softening thickness is 10 μm or more and 100 μm or less, and the amount of low temperature range diffusible hydrogen is 0.015 mass ppm or less.

公开(公告)号：US20230407484A1

公开(公告)日：2023-12-21

申请号：US18251242

申请日：2021-11-05

Applicant: JFE STEEL CORPORATION

Inventor： Shunsuke YAMAMOTO ,  Katsutoshi TAKASHIMA ,  Yusuke OKUMURA ,  Tomomi KANAZAWA ,  Katsuya HOSHINO ,  Takashi KAWANO ,  Takako YAMASHITA ,  Hiroshi MATSUDA ,  Yoichi MAKIMIZU

IPC: C23C28/02 ,  C23C2/28 ,  C23C2/06 ,  C22C38/02 ,  C25D3/20 ,  C23C2/02 ,  C22C38/06 ,  C22C38/04 ,  C21D8/02

CPC classification number: C23C28/021 ,  C23C2/28 ,  C23C2/06 ,  C22C38/02 ,  C25D3/20 ,  C23C2/022 ,  C22C38/06 ,  C22C38/04 ,  C21D8/0236

Abstract: Disclosed is a galvannealed steel sheet including: a Si-containing cold-rolled steel sheet containing Si in an amount of 0.1 mass % or more and 3.0 mass % or less; an Fe-based electroplating layer formed on at least one surface of the Si-containing cold-rolled steel sheet; and a galvannealed layer formed on the Fe-based electroplating layer, in which in an intensity profile measured by glow discharge optical emission spectrometry, ISi,Fe/ISi,bulk is 0.30 or more, and an average value of C concentration in a region ranging from 10 μm to 20 μm in the thickness direction from the interface between the galvannealed layer and the Fe-based electroplating layer towards the Fe-based electroplating layer is 0.10 mass % or less.

公开(公告)号：US20220403480A1

公开(公告)日：2022-12-22

申请号：US17821476

申请日：2022-08-23

Applicant: JFE STEEL CORPORATION

Inventor： Gentaro TAKEDA ,  Yoichi MAKIMIZU ,  Yoshikazu SUZUKI ,  Yoshimasa HIMEI ,  Hideyuki TAKAHASHI

IPC: C21D9/46 ,  C21D1/26 ,  C21D1/74 ,  C21D8/02 ,  C21D9/00 ,  C22C38/02 ,  C23C2/00 ,  C23C2/06 ,  C23C2/26 ,  C23C2/40

Abstract: A continuous hot-dip galvanizing apparatus has a vertical annealing furnace, one or more hearth rolls, a hot-dip galvanizing apparatus, an alloying line, and humidified gas supply ports. When the steel sheet having a Si content of 0.2 mass % or more is conveyed inside the annealing furnace, the humidified gas supply ports positioned in a latter part of the soaking zone supply the humidified gas to the soaking zone and the at least one dry gas supply port supplies the dry gas to the soaking zone. When the steel sheet having a Si content of less than 0.2 mass % is conveyed inside the annealing furnace, the plurality of the humidified gas supply ports do not supply the humidified gas to the soaking zone and the at least one dry gas supply port supplies the dry gas to the soaking zone.

公开(公告)号：US20200299799A1

公开(公告)日：2020-09-24

申请号：US16605305

申请日：2018-02-19

Applicant: JFE STEEL CORPORATION

Inventor： Gentaro TAKEDA ,  Yoichi MAKIMIZU ,  Yoshikazu SUZUKI ,  Yoshimasa HIMEI ,  Hideyuki TAKAHASHI

IPC: C21D9/46 ,  C21D9/00 ,  C21D1/26 ,  C21D1/74 ,  C21D8/02 ,  C23C2/00 ,  C23C2/06 ,  C23C2/26 ,  C23C2/40 ,  C22C38/02

Abstract: Provided is a method for producing a galvannealed steel sheet. When the steel sheet passing through the soaking zone is a type of steel containing 0.2 mass % or more of Si, both dry gas and humidified gas are supplied to the soaking zone, where the humidified gas is supplied only from the humidified gas supply port positioned in a latter part of the soaking zone among a plurality of humidified gas supply ports, where the latter part of the soaking zone is determined considering a sheet passing speed V and a target temperature T on the exit side of the soaking zone.

公开(公告)号：US20180237896A1

公开(公告)日：2018-08-23

申请号：US15753260

申请日：2016-08-05

Applicant: JFE STEEL CORPORATION

Inventor： Gentaro TAKEDA ,  Hideyuki TAKAHASHI ,  Yoichi MAKIMIZU ,  Yoshikazu SUZUKI ,  Yoshimasa HIMEI

IPC: C23C2/02 ,  C23C2/40 ,  C23C2/28 ,  C23C2/06 ,  C21D1/76 ,  C21D9/56 ,  C21D9/573

CPC classification number: C23C2/02 ,  C21D1/76 ,  C21D9/561 ,  C21D9/573 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40

Abstract: A method includes: annealing a steel strip by conveying the steel strip through a heating zone, a soaking zone, and a cooling zone in this order inside an annealing furnace; and applying a hot-dip galvanized coating onto the steel strip discharged from the cooling zone. Reducing gas or non-oxidizing gas supplied into the soaking zone includes humidified gas and dry gas. While a width and a sheet passing speed of the steel strip passing through the soaking zone are constant, a variation of pressure in the annealing furnace is suppressed by adjusting a flow rate of the dry gas, and a variation range of an amount of moisture supplied into the soaking zone by the humidified gas is limited to 20% or less.

公开(公告)号：US20230407447A1

公开(公告)日：2023-12-21

申请号：US18251422

申请日：2021-11-05

Applicant: JFE STEEL CORPORATION

Inventor： Shunsuke YAMAMOTO ,  Katsutoshi TAKASHIMA ,  Mai AOYAMA ,  Yusuke OKUMURA ,  Tomomi KANAZAWA ,  Katsuya HOSHINO ,  Hiroshi MATSUDA ,  Ei OKUMURA ,  Yoichi MAKIMIZU ,  Masaki KOBA

IPC: C23C2/02 ,  C22C33/04 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/38 ,  C22C38/32 ,  C22C38/28 ,  C21D9/46 ,  C21D8/02 ,  C21D6/00 ,  C22C38/00 ,  C21D1/74 ,  C25D5/36 ,  C25D5/48 ,  C25D3/56 ,  C23C2/28 ,  C23C2/40 ,  C23F17/00 ,  C23C28/00

CPC classification number: C23C2/02 ,  C22C33/04 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/38 ,  C22C38/32 ,  C22C38/28 ,  C21D9/46 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0263 ,  C21D8/0278 ,  C21D6/002 ,  C21D6/005 ,  C21D6/008 ,  C22C38/002 ,  C22C38/001 ,  C21D1/74 ,  C25D5/36 ,  C25D5/48 ,  C25D3/562 ,  C23C2/28 ,  C23C2/40 ,  C23F17/00 ,  C23C28/34 ,  C23C28/321 ,  C21D2251/02 ,  B23K11/166

Abstract: Provided is a galvanized steel sheet with excellent resistance to cracking in resistance welding at a welded portion, even if crystal orientations of an Fe-based electroplating layer and a cold-rolled steel sheet are integrated at a high ratio at the interface between the Fe-based electroplating layer and the cold-rolled steel sheet. The galvanized steel sheet has a Si-containing cold-rolled steel sheet containing Si in an amount of 0.1 mass % to 3.0 mass %; an Fe-based electroplating layer formed on at least one surface of the Si-containing cold-rolled steel sheet with a coating weight per surface of more than 20.0 g/m2, and a galvanized layer formed on the Fe-based electroplating layer, where crystal orientations of the Fe-based electroplating layer and the Si-containing cold-rolled steel sheet are integrated at a ratio of more than 50 % at the interface between the Fe-based electroplating layer and the Si-containing cold-rolled steel sheet.

公开(公告)号：US20190040511A1

公开(公告)日：2019-02-07

申请号：US16072904

申请日：2017-01-26

Applicant: JFE STEEL CORPORATION

Inventor： Hiroshi HASEGAWA ,  Yoshimasa FUNAKAWA ,  Hiromi YOSHITOMI ,  Yoichi MAKIMIZU ,  Yoshitsugu SUZUKI ,  Gentaro TAKEDA ,  Yoshikazu SUZUKI ,  Yoshimasa HIMEI

IPC: C23C2/02 ,  C22C38/60 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C21D9/46 ,  C23C2/06 ,  C23C2/26 ,  C23C2/40

Abstract: A high-strength galvanized steel sheet having improved post-work impact resistance, a method for producing the high-strength galvanized steel sheet, and a high-strength member produced using the steel sheet. The high-strength galvanized steel sheet includes a steel sheet having a microstructure including ferrite and carbide-free bainite, martensite and carbide-containing bainite, and retained austenite, the total area fraction of ferrite and carbide-free bainite being 0% to 55%, the total area fraction of martensite and carbide-containing bainite being 45% to 100%, and the area fraction of retained austenite being 0% to 5%. Additionally, a galvanizing layer is disposed on the steel sheet. The density of gaps that cut across the entire thickness of the galvanizing layer in a cross section of the galvanizing layer, which is taken in the thickness direction so as to be perpendicular to the rolling direction, is 10 gaps/mm or more.

公开(公告)号：US20180051356A1

公开(公告)日：2018-02-22

申请号：US15541401

申请日：2015-12-18

Applicant: JFE STEEL CORPORATION

Inventor： Gentaro TAKEDA ,  Masaru MIYAKE ,  Yoichi MAKIMIZU ,  Yoshitsugu SUZUKI

IPC: C21D9/56 ,  C21D9/46 ,  C21D1/76 ,  C23C2/02 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40 ,  C21D6/00 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  F27D7/06 ,  F27D7/02

CPC classification number: C21D9/561 ,  C21D1/74 ,  C21D1/76 ,  C21D6/005 ,  C21D6/008 ,  C21D9/46 ,  C21D9/56 ,  C22C38/002 ,  C22C38/02 ,  C22C38/04 ,  C23C2/02 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40 ,  F27B9/045 ,  F27B9/28 ,  F27D7/02 ,  F27D7/06 ,  F27D2007/063

Abstract: A method of producing a galvannealed steel sheet whereby favorable coating appearance can be obtained with high coating adhesion even in the case of galvannealing a steel strip whose Si content is 0.2 mass % or more, and a decrease in tensile strength can be prevented by lowering the alloying temperature. Mixed gas of humidified gas and dry gas, and dry gas are supplied to a soaking zone in an annealing furnace. The mixed gas is timely supplied from a position of lower half of the soaking zone. The dry gas is timely supplied from near an upper hearth roll in the soaking zone, and furnace gas is timely discharged from a gas discharge port located higher than the upper hearth roll, to control a dew point in at least an uppermost part of the soaking zone to −20° C. or more and 0° C. or less.

公开(公告)号：US20180030564A1

公开(公告)日：2018-02-01

申请号：US15543271

申请日：2015-11-24

Applicant: JFE STEEL CORPORATION

Inventor： Hiroshi HASEGAWA ,  Hideyuki KIMURA ,  Yoshimasa FUNAKAWA ,  Yoichi MAKIMIZU ,  Yoshitsugu SUZUKI

IPC: C21D9/46 ,  C22C38/26 ,  C22C38/24 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/08 ,  C22C38/06 ,  C22C38/02 ,  C22C38/00 ,  C21D8/02 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40 ,  C21D6/00 ,  C22C38/38

CPC classification number: C21D9/46 ,  B32B15/013 ,  B32B15/04 ,  B32B15/043 ,  B32B15/18 ,  C21D6/001 ,  C21D6/002 ,  C21D6/005 ,  C21D6/008 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0263 ,  C21D8/0463 ,  C21D8/0473 ,  C21D2211/001 ,  C21D2211/005 ,  C21D2211/008 ,  C22C38/00 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/08 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/24 ,  C22C38/26 ,  C22C38/38 ,  C22C38/58 ,  C23C2/02 ,  C23C2/06 ,  C23C2/12 ,  C23C2/28 ,  C23C2/285 ,  C23C2/40 ,  C23C30/00 ,  C23C30/005 ,  Y10T428/12757 ,  Y10T428/12799 ,  Y10T428/12951 ,  Y10T428/12958 ,  Y10T428/12972

Abstract: A high-strength galvanized steel sheet and method for producing the same. The high-strength galvanized steel sheet including a specified chemical composition and a microstructure comprising, in terms of area fraction, a tempered martensite phase: 30% or more and 73% or less, a ferrite phase: 25% or more and 68% or less, a retained austenite phase: 2% or more and 15% or less, and other phases: 10% or less (including 0%), the other phases comprising a martensite phase: 3% or less (including 0%) and a bainitic ferrite phase: less than 5% (including 0%), the tempered martensite phase having an average grain size of 8 μm or less, the ferrite phase having an average grain size of 5 μm or less, and the retained austenite phase having a C content less than 0.7% by mass.