公开(公告)号：CA2684031C

公开(公告)日：2016-01-12

申请号：CA2684031

申请日：2008-04-07

Applicant: JFE STEEL CORP

Inventor： TAKAGI SHUSAKU ,  KAWABE HIDETAKA ,  HASEGAWA KOHEI ,  OOI TOSHIHIKO ,  OKITA YASUAKI ,  SAKURAI MICHITAKA

IPC: C22C38/38 ,  C21D8/02 ,  C21D9/46 ,  C23C2/06 ,  C23C2/28

Abstract: A high tensile-strength galvanized steel sheet, comprising: C: at least 0.05% but less than 0.12%, Si: at least 0.01% but less than 0.35%, Mn: 2.0% to 3.5%, P: 0.001% to 0.020%, S: 0.0001% to 0.0030%, Al: 0.005% to 0.1%, N: 0.0001% to 0.0060%, Cr: more than 0.5% but not more than 2.0%, Mo: 0.01% to 0.50%, Ti: 0.010% to 0.080%, Nb: 0.010% to 0.080%, and B: 0.0001% to 0.0030%, the remainder being Fe and unavoidable impurities, wherein the high tensile-strength galvanized steel sheet has a microstructure that contains 20% to 70% by volume ferrite having an average grain size of 5 µm or less. The high tensile-strength galvanized steel sheet has a tensile strength of at least 980 MPa, and excellent formability and weldability. Selected Figure: None

公开(公告)号：CA2684031A1

公开(公告)日：2008-11-06

申请号：CA2684031

申请日：2008-04-07

Applicant: JFE STEEL CORP

Inventor： SAKURAI MICHITAKA ,  OKITA YASUAKI ,  HASEGAWA KOHEI ,  OOI TOSHIHIKO ,  KAWABE HIDETAKA ,  TAKAGI SHUSAKU

IPC: C22C38/38 ,  C21D8/02 ,  C21D9/46 ,  C23C2/06 ,  C23C2/28

Abstract: Disclosed is a high-strength hot-dip galvanized steel sheet having a comp osition consisting of not less than 0.05% but less than 0.12% of C, not less than 0.01% but less than 0.35% of Si, 2.0-3.5% of Mn, 0.001-0.020% of P, 0. 0001-0.0030% of S, 0.005-0.1% of Al, 0.0001-0.0060% of N, more than 0.5% but not more than 2.0% of Cr, 0.01-0.50% of Mo, 0.010-0.080% of Ti, 0.010-0.080 % of Nb and 0.0001-0.0030% of B and the balance of Fe and unavoidable impuri ties, while having a structure containing a ferrite phase having a volume fr action of 20-70% and an average crystal grain size of not more than 5 .mu.m. This high-strength hot-dip galvanized steel sheet has a high tensile streng th of not less than 980 MPa (TS >= 980 MPa), while being excellent in pro cessability and weldability.

公开(公告)号：EP2979806A4

公开(公告)日：2016-06-15

申请号：EP14772698

申请日：2014-01-24

Applicant: JFE STEEL CORP

Inventor： OKITA YASUAKI ,  SAWANISHI CHIKAUMI ,  IKEDA RINSEI

IPC: B23K11/24 ,  B23K11/11 ,  B23K11/25

CPC classification number: B23K11/115 ,  B23K11/252 ,  B23K11/255

公开(公告)号：EP2769797A4

公开(公告)日：2016-02-17

申请号：EP12841263

申请日：2012-10-17

Applicant: JFE STEEL CORP

Inventor： TANIGUCHI KOICHI ,  OKITA YASUAKI ,  IKEDA RINSEI

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

CPC classification number: B23K11/115 ,  B23K11/24 ,  B23K11/241 ,  B23K11/257

公开(公告)号：EP3228414A4

公开(公告)日：2017-12-13

申请号：EP15865842

申请日：2015-11-18

Applicant: JFE STEEL CORP

Inventor： SAWANISHI CHIKAUMI ,  OKITA YASUAKI ,  MATSUDA HIROSHI ,  IKEDA RINSEI

IPC: B23K11/20 ,  B23K11/11 ,  B23K11/16 ,  B23K11/24

CPC classification number: B23K11/11 ,  B23K11/115 ,  B23K11/16 ,  B23K11/24 ,  B23K11/362

Abstract: A resistance spot welding method with which a nugget of an appropriate diameter can be obtained without splashing regardless of disturbances such as a sheet gap or current shunting in a sheet combination with a high sheet thickness ratio in which a thin sheet is overlapped on one face of two or more overlapping thick sheets is provided. 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 F 1 > F 2.

公开(公告)号：EP3078444A4

公开(公告)日：2016-11-30

申请号：EP14868526

申请日：2014-12-04

Applicant: JFE STEEL CORP

Inventor： TANIGUCHI KOICHI ,  OKITA YASUAKI ,  IKEDA RINSEI

IPC: B23K11/16 ,  B23K11/00 ,  B23K11/11 ,  B23K11/24 ,  B23K101/00 ,  B23K101/18 ,  B23K101/34 ,  B23K103/04

CPC classification number: B23K11/115 ,  B23K11/0026 ,  B23K11/166 ,  B23K2201/006 ,  B23K2201/18 ,  B23K2201/34 ,  B23K2203/04

Abstract: Resistance spot welding is performed on a combination of overlapping steel sheets including at least one steel sheet that has, on a surface thereof, a coated layer with zinc as a main component, by (1) starting electric current passage in a state satisfying 0.9 × t ‰¤ L ‰¤ 1.1 × t, where t is the total thickness of the overlapping steel sheets and L is the distance between tips of upper and lower electrodes; and (2) dividing electric current into main current and initial current that precedes the main current and is two-step current, setting a current value I 1 during current in a first step of the initial current to satisfy I m × 1.1 ‰¤ I 1 ‰¤ 15.0 kA with respect to a current value I m during the main current, and setting a current value I 2 in the subsequent second step to no current or low current satisfying 0 ‰¤ I 2 ‰¤ I m × 0.7, thereby stably forming a nugget of sufficient diameter, without the occurrence of splashing.

公开(公告)号：EP3266533A4

公开(公告)日：2018-07-25

申请号：EP16758649

申请日：2016-03-03

Applicant: JFE STEEL CORP

Inventor： OKITA YASUAKI ,  IKEDA RINSEI ,  NAKAJIMA SEIJI ,  NAKAGAWA KOICHI

IPC: B21D22/20 ,  B23K9/16 ,  B23K9/167 ,  B23K9/23 ,  B23K10/02 ,  B23K26/21 ,  B23K26/322 ,  B23K26/348 ,  B23K31/00 ,  C21D1/18 ,  C21D9/00 ,  C22C18/00 ,  C22C18/04 ,  C22C38/00 ,  C22C38/60 ,  C23C2/06 ,  C23C2/40

CPC classification number: C21D9/50 ,  B21D22/20 ,  B21D22/208 ,  B21D53/88 ,  B23K9/16 ,  B23K9/167 ,  B23K9/23 ,  B23K10/02 ,  B23K26/21 ,  B23K26/348 ,  B23K31/00 ,  B23K2203/08 ,  C21D1/18 ,  C21D9/00 ,  C22C18/00 ,  C22C18/04 ,  C22C38/00 ,  C22C38/001 ,  C22C38/002 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/28 ,  C22C38/60 ,  C23C2/06 ,  C23C2/40

Abstract: A hot-pressed member is formed using a tailored blank material obtained by butt joining respective ends of two or more coated steel sheets. The hot-pressed member has two or more sites formed by the respective coated steel sheets and at least one joining portion between the sites. Depending on a type of a coated layer of each of the coated steel sheets, t w /t 0 is appropriately controlled where t w is a thickness of a thinnest portion in the joining portion and t 0 is a thickness of a thinnest site of the sites. A tensile strength of each of the sites is 1180 MPa or more.

公开(公告)号：EP2965848A4

公开(公告)日：2016-06-08

申请号：EP14759633

申请日：2014-01-24

Applicant: JFE STEEL CORP

Inventor： OKITA YASUAKI ,  SAWANISHI CHIKAUMI ,  IKEDA RINSEI ,  OI KENJI

IPC: B23K11/24 ,  B23K11/11

CPC classification number: B23K11/115 ,  B23K11/24

Abstract: Proposed is a method of resistance spot welding to join a plurality of overlapping metal sheets, including: dividing a current pattern into two or more steps for welding; before actual welding, performing test welding to store, for each step as a target value, a time variation of an instantaneous amount of heat generated per unit volume and a cumulative amount of heat generated per unit volume that are calculated from an electrical property between electrodes when forming an appropriate nugget by passing current with constant current control; and subsequently, as actual welding, starting welding using, as a standard, a time variation curve of the instantaneous amount of heat generated per unit volume obtained by the test welding, and when a time variation amount of an instantaneous amount of heat generated deviates during any step from the time variation curve by a difference, performing adaptive control welding to control a current passage amount in order to compensate for the difference during a remaining welding time in the step so as to match a cumulative amount of heat generated in the actual welding to the cumulative amount of heat generated that is determined in advance in the test welding. This method thus effectively addresses wear of the electrode tip and the presence of a disturbance and obtains a good nugget.

公开(公告)号：EP2138599A4

公开(公告)日：2014-10-22

申请号：EP08740312

申请日：2008-04-07

Applicant: JFE STEEL CORP

Inventor： TAKAGI SHUSAKU ,  KAWABE HIDETAKA ,  HASEGAWA KOHEI ,  OOI TOSHIHIKO ,  OKITA YASUAKI ,  SAKURAI MICHITAKA

IPC: C22C38/38 ,  C21D6/00 ,  C21D8/02 ,  C21D8/04 ,  C21D9/46 ,  C21D9/48 ,  C22C38/00 ,  C22C38/02 ,  C22C38/06 ,  C22C38/22 ,  C22C38/26 ,  C22C38/28 ,  C22C38/32 ,  C23C2/02 ,  C23C2/06 ,  C23C2/28

CPC classification number: C23C2/06 ,  C21D6/005 ,  C21D8/0426 ,  C21D8/0473 ,  C21D8/0478 ,  C21D9/46 ,  C21D9/48 ,  C21D2211/002 ,  C21D2211/005 ,  C21D2211/008 ,  C22C38/001 ,  C22C38/02 ,  C22C38/06 ,  C22C38/22 ,  C22C38/26 ,  C22C38/28 ,  C22C38/32 ,  C22C38/38 ,  C23C2/02 ,  C23C2/28 ,  Y10T428/12799

Abstract: A high tensile-strength galvanized steel sheet, comprising: C: at least 0.05% but less than 0.12%, Si: at least 0.01% but less than 0.35%, Mn: 2.0% to 3.5%, P: 0.001% to 0.020%, S: 0.0001% to 0.0030%, Al: 0.005% to 0.1%, N: 0.0001% to 0.0060%, Cr: more than 0.5% but not more than 2.0%, Mo: 0.01% to 0.50%, Ti: 0.010% to 0.080%, Nb: 0.010% to 0.080%, and B: 0.0001% to 0.0030%, the remainder being Fe and unavoidable impurities, wherein the high tensile-strength galvanized steel sheet has a microstructure that contains 20% to 70% by volume ferrite having an average grain size of 5 µm or less. The high tensile-strength galvanized steel sheet has a tensile strength of at least 980 MPa, and excellent formability and weldability.

公开(公告)号：EP3266554A4

公开(公告)日：2018-03-14

申请号：EP16758648

申请日：2016-03-03

Applicant: JFE STEEL CORP

Inventor： TANIGUCHI KOICHI ,  OKITA YASUAKI ,  IKEDA RINSEI

IPC: B23K11/11 ,  B23K11/16 ,  B23K11/25 ,  B23K101/00 ,  B23K103/04

CPC classification number: B23K11/241 ,  B23K11/11 ,  B23K11/115 ,  B23K11/16 ,  B23K11/25 ,  B23K11/253 ,  B23K11/255 ,  B23K2201/006 ,  B23K2203/05

Abstract: A resistance spot welding method is provided, which allows a large nugget to be formed while the occurrence of expulsion is prevented. The resistance spot welding device according to the present invention is a resistance spot welding device for welding at least two overlapping steel sheets held between a pair of welding electrodes. The resistance spot welding device includes the pair of electrodes, an electrode force gauge that measures an electrode force, and a controller that controls an electric current supply to the electrodes according to the electrode force measured by the electrode force gauge. The controller controls the electric current such that the electrode force F measured by the electrode force gauge after the start of the electric current supply is adjusted to a prescribed value.