公开(公告)号：US20240117517A1

公开(公告)日：2024-04-11

申请号：US18250978

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: C25D3/20 ,  C21D8/02 ,  C21D9/46 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C25D7/06

CPC classification number: C25D3/20 ,  C21D8/0236 ,  C21D8/0257 ,  C21D9/46 ,  C22C38/001 ,  C22C38/002 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C25D7/0614

Abstract: Disclosed is an Fe-based electroplated 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; and 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 5.0 g/m2 or more, in which in an intensity profile measured by glow discharge optical emission spectrometry, a peak of emission intensity at wavelengths indicating Si is detected within a range from a surface of the Fe-based electroplating layer to more than 0.2 μm in a thickness direction and not more than a thickness of the Fe-based electroplating layer, and an average value of C concentration in a region ranging from 10 μm to 20 μm in the thickness direction from the surface of the Fe-based electroplating layer is 0.10 mass % or less.

公开(公告)号：US20230407485A1

公开(公告)日：2023-12-21

申请号：US18251269

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: C23C28/02 ,  C21D9/46 ,  C22C38/38 ,  C22C38/32 ,  C22C38/28 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C21D6/00 ,  C22C33/04 ,  C21D8/02 ,  C21D1/74 ,  C25D3/20 ,  C25D5/36

CPC classification number: C23C28/021 ,  C21D9/46 ,  C22C38/38 ,  C22C38/32 ,  C22C38/28 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/08 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/002 ,  C22C38/001 ,  C21D6/001 ,  C21D6/002 ,  C21D6/005 ,  C21D6/008 ,  C22C33/04 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0263 ,  C21D1/74 ,  C21D8/0278 ,  C25D3/20 ,  C25D5/36 ,  C21D2251/02 ,  C23C2/28

Abstract: Provided is an alloyed 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 alloyed 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 exceeding 20.0 g/m2, and an alloyed 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：US20230347440A1

公开(公告)日：2023-11-02

申请号：US18011567

申请日：2021-06-22

Applicant: JFE STEEL CORPORATION

Inventor： Daiki YAMAGISHI ,  Katsutoshi TAKASHIMA ,  Hiroshi MATSUDA

IPC: C22C38/38 ,  C22C38/26 ,  C22C38/14 ,  C22C38/60 ,  C22C38/02 ,  C22C38/12 ,  B23K11/14 ,  C22C38/28 ,  C22C38/16 ,  C22C38/10 ,  C22C38/06 ,  C22C38/04 ,  C22C38/00

CPC classification number: B23K11/14 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/105 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/26 ,  C22C38/28 ,  C22C38/38 ,  C22C38/60

Abstract: A projection welded joint is formed by joining a steel sheet having a tensile strength of 980 MPa or higher and a nut by performing projection welding. In a hardness distribution from the steel sheet to the nut through a weld metal zone, and a hardened region exists on each of the steel sheet side and the nut side. A hardness of each hardened region is higher than that of the base metal on the corresponding side, and each hardened region extends continuously for a distance of 500 µm or more. The maximum hardness NHmax on the nut side is higher than the maximum hardness SHmax on the steel sheet side. A region where the maximum hardness SHmax on the steel sheet side exists is formed of a martensite microstructure having a prior austenite grain size of 20 µm or less.

公开(公告)号：US20230271270A1

公开(公告)日：2023-08-31

申请号：US18018140

申请日：2021-07-26

Applicant: JFE STEEL CORPORATION

Inventor： Naoaki MUNEMURA ,  Hiroshi MATSUDA ,  Yoshiaki MURAKAMI

IPC: B23K20/12

CPC classification number: B23K20/1255 ,  B23K2101/18

Abstract: An element, a friction element welding method, and a method for producing a friction element welded joint. The element is for performing friction element welding on a sheet stack of two or more stacked metal sheets by pressing the element into the sheet stack while the element is rotated. The element includes a circular columnar mandrel that is to enter the sheet stack, a circular collar disposed at an upper end portion of the mandrel, a first conical body extending from a lower end surface of the mandrel, and a second conical body disposed on the lower side of the first conical body. The vertical angle β of the second conical body and the vertical angle α of the first conical body satisfy the relation β

公开(公告)号：US20210260684A1

公开(公告)日：2021-08-26

申请号：US17252276

申请日：2019-06-17

Applicant: JFE STEEL CORPORATION

Inventor： Chikaumi SAWANISHI ,  Hiroshi MATSUDA ,  Rinsei IKEDA

IPC: B23K11/11 ,  B23K11/25 ,  B23K31/12

Abstract: A resistance spot welding method comprises: performing test welding; and performing actual welding after the test welding, wherein in subsequent current passage in the test welding, current passage is performed by constant current control under a condition: 0.5≤Vtp/Vtm≤2.0 when tc

公开(公告)号：US20210023646A1

公开(公告)日：2021-01-28

申请号：US16635165

申请日：2018-08-02

Applicant: JFE STEEL CORPORATION

Inventor： Chikaumi SAWANISHI ,  Hiroshi MATSUDA ,  Rinsei IKEDA

IPC: B23K11/11 ,  B23K11/25

Abstract: A resistance spot welding method comprises: performing test welding; and performing actual welding after the test welding. The test welding is performed under each of two or more welding conditions. In the actual welding, preliminary current passage is performed by constant current control in the same current pattern as in the preliminary current passage of the test welding, an electrical property between the electrodes in the preliminary current passage in the actual welding and an electrical property between the electrodes stored in the preliminary current passage in the test welding are compared for each welding condition to set a target in main current passage in the actual welding, and thereafter adaptive control welding is performed to control a current passage amount as the main current passage.

公开(公告)号：US20190119773A1

公开(公告)日：2019-04-25

申请号：US16221890

申请日：2018-12-17

Applicant: JFE STEEL CORPORATION

Inventor： Hiroshi MATSUDA ,  Hideyuki TAKAHASHI ,  Hiroi YAMAGUCHI ,  Yasuyuki HAYAKAWA ,  Yukihiro SHINGAKI ,  Takashi TERASHIMA

IPC: C21D8/12 ,  C23C8/80 ,  H01F1/16 ,  C23C8/38 ,  H01J37/32 ,  C23C8/02 ,  H01F41/02 ,  C23C8/26 ,  C21D9/46 ,  C21D9/00

Abstract: Provided is a method for nitriding a grain-oriented electrical steel sheet which is very useful in obtaining excellent magnetic properties with no variation, that enables generating glow discharge between positive electrodes and negative electrodes disposed in a nitriding zone and irradiating the generated plasma to a strip to perform appropriate nitriding.

公开(公告)号：US20170312846A1

公开(公告)日：2017-11-02

申请号：US15526125

申请日：2015-11-18

Applicant: JFE STEEL CORPORATION

Inventor： Chikaumi SAWANISHI ,  Yasuaki OKITA ,  Hiroshi MATSUDA ,  Rinsei IKEDA

IPC: B23K11/11 ,  B23K11/16 ,  B23K11/24 ,  B23K11/36

Abstract: The resistance spot welding method includes performing actual welding to squeeze, by a pair of electrodes (14), a sheet combination with a sheet thickness ratio of more than 3 in which a thin sheet (11) is overlapped on at least one face of two or more overlapping thick sheets (12, 13), and passing a current while applying an electrode force to join the sheet combination, wherein in the actual welding, a pattern of the current and the electrode force is divided into two or more steps including a first step and a second step to perform welding, and an electrode force F1 in the first step and an electrode force F2 in the second step satisfy a relationship F1>F2.

公开(公告)号：US20170218472A1

公开(公告)日：2017-08-03

申请号：US15326116

申请日：2015-08-05

Applicant: JFE STEEL CORPORATION

Inventor： Yoshiyasu KAWASAKI ,  Hiroshi MATSUDA ,  Kazunori TAHARA ,  Takeshi YOKOTA ,  Kaneharu OKUDA ,  Kazuhiro SETO

IPC: C21D9/46 ,  C23C2/28 ,  C23C2/40 ,  C22C38/60 ,  C22C38/38 ,  C22C38/16 ,  C22C38/14 ,  C22C38/12 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C21D8/02 ,  C21D1/60 ,  C23G1/00 ,  B32B15/01 ,  C23C2/06

CPC classification number: C21D9/46 ,  B32B15/013 ,  C21D1/60 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0263 ,  C21D8/0278 ,  C21D2211/001 ,  C21D2211/002 ,  C21D2211/005 ,  C21D2211/008 ,  C22C38/00 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/008 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/38 ,  C22C38/60 ,  C23C2/06 ,  C23C2/28 ,  C23C2/40 ,  C23G1/00

Abstract: Disclosed is a high-strength steel sheet having a tensile strength (TS) of 780 MPa or more and excellent in ductility, fatigue properties, stretch flangeability, surface characteristics, and sheet passage ability that can be obtained by providing a predetermined chemical composition and a steel microstructure that contains, by area, 20-50% of ferrite, 5-25% of bainitic ferrite, 1-10% of martensite, and 5-15% of tempered martensite, and that contains, by volume, 10% or more of retained austenite, in which the retained austenite has a mean grain size of 2 μm or less, a mean Mn content in the retained austenite in mass % is at least 1.2 times the Mn content in the steel sheet in mass %, the retained austenite has a mean free path of 1.2 μm or less, and the tempered martensite has a mean free path of 1.2 μm or less.

公开(公告)号：US20170204490A1

公开(公告)日：2017-07-20

申请号：US15326540

申请日：2015-08-05

Applicant: JFE STEEL CORPORATION

Inventor： Yoshiyasu KAWASAKI ,  Hiroshi MATSUDA ,  Yoshie OBATA ,  Shinjiro KANEKO ,  Takeshi YOKOTA ,  Kazuhiro SETO

IPC: C21D9/46 ,  C21D6/00 ,  C22C38/60 ,  C22C38/38 ,  C23F17/00 ,  C22C38/14 ,  C22C38/12 ,  C22C38/06 ,  C22C38/00 ,  C23C2/06 ,  C21D8/02 ,  C22C38/16

CPC classification number: C21D9/46 ,  C21D6/005 ,  C21D6/008 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0236 ,  C21D8/0263 ,  C21D8/0273 ,  C21D8/0278 ,  C21D2211/001 ,  C21D2211/002 ,  C21D2211/005 ,  C21D2211/008 ,  C22C18/04 ,  C22C38/00 ,  C22C38/001 ,  C22C38/002 ,  C22C38/005 ,  C22C38/008 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/12 ,  C22C38/14 ,  C22C38/16 ,  C22C38/38 ,  C22C38/60 ,  C23C2/02 ,  C23C2/06 ,  C23F17/00

Abstract: Disclosed is a high-strength steel sheet having a predetermined chemical composition and a steel microstructure that contains, by area, 25-80% of ferrite and bainitic ferrite in total, and 3-20% of martensite, and that contains, by volume, 10% or more of retained austenite, in which the retained austenite has a mean grain size of 2 μm or less, a mean Mn content in the retained austenite in mass % is at least 1.2 times the Mn content in the steel sheet in mass %, an area ratio of retained austenite having a mean C content in mass % at least 2.1 times the C content in the steel sheet in mass % is 60% or more of an area ratio of the entire retained austenite.