Nippon Steel Corporation

Nippon Steel Sumitomo Metal Corporation

Sumitomo Metal Industries, Inc.

Toyota Jidosha Kabushiki Kaisha

Kabushiki Kaisha Square Enix

Hiroki Fujimoto

Masanori Yasuyama

Tohru Okada

Yoshiaki Nakazawa

Masahiro Nakata

Shintaro Yamanaka

Takashi Imamura

Kotaro Watanabe

Hatsuhiko Oikawa

Tatsuya Kumagai

Yasuhito Totsuka

Yasuhiro Ito

Toshiya Suzuki

Koichi Hamada

Jun Maki

Kenichiro Otsuka

Takehiro Takahashi

Atsushi Ono

Soshi Fujita

Satoshi Hirose

Keisuke Uchida

Takuya Okada

Hideaki Irikawa

Koji Akioka

Toshiyuki Manabe

Masahito Tasaka

Masahiro Nishio

Kouhei Miyazaki

Hitomi Nishibata

Takashi Tokita

Hideo Iwasaki

Tasuku Zeniya

Yujiro Tatsumi

Masaki Tanzawa

Masatoshi Tokunaga

Hironari Mikata

Kouki Takahashi

Yuichi Tsukeshiba

Misaki Asada

Hatsushiko Oikawa

Masaki Ohno

Shinji Ihata

Hiroshi Miyajima

A method for manufacturing a riveted joint includes: causing a shaft portion of a steel rivet having the shaft portion and a head portion to pass through through-holes of a plurality of overlaid sheet members; sandwiching the rivet between a pair of electrodes in axial direction of the rivet; applying a force to the rivet and energizing the rivet with the electrodes to form a deformed portion at a distal end of the shaft portion; and cooling the rivet. In the rivet after cooling, a Vickers hardness HB of the head portion satisfies 130≤HB≤330, and a Vickers hardness HA of the deformed portion, a thickness TA of the deformed portion, a Vickers hardness HJ of a portion of the shaft portion at center in axial direction and at center in radial direction, diameter DJ of the shaft portion, a Vickers hardness HB of the head portion, and a thickness TB of the head portion satisfy HJ×DJ≥4.7×HB×TB and HA×TA≥1.3×HB×TB.

Method for manufacturing riveted joint, riveted joint, and vehicle component

To obtain a welded member using a steel sheet less expensive than a pure Ni sheet as a raw material and excellent in corrosion resistance. A welded member according to the present invention is made by connecting a Ni plated steel sheet having a Ni plating layer and a Fe—Ni diffusion alloy layer and another steel sheet via a welded part, wherein: a Ni concentration is 70 mass % or more and a Fe concentration is 30 mass % or less in a surface layer of each of a toe, a toe near area, and the welded part; and a thickness of the Fe—Ni diffusion alloy layer is 0.5 to 1.5 μm and a total thickness of the Ni plating layer and the Fe—Ni diffusion alloy layer is 2.7 to 14.0 μm at a non-welded part, and a total concentration of S and C in the Ni plating layer at the non-welded part is less than 20 ppm.

Welded member

A welded joint manufacturing method includes: abutting a first electrode against a first steel sheet of a welded joint at a site A, which is a location at an outer side of a nugget in a sheet-plane direction in a plane running parallel to the first steel sheet; abutting a second electrode against a second steel sheet at a site B, which is a location at an outer side of the nugget in a sheet-plane direction in a plane running parallel to the first steel sheet of the welded joint, and positioned on an opposite side of the nugget from the site A; and passing a current through the welded joint between the first electrode and the second electrode.

Welded joint manufacturing method, welded joint, tempering device, and welding apparatus

A tailored blank including a first steel sheet having a carbon content of 0.27 mass % or more, and a second steel sheet that is butt welded to the first steel sheet and that has a carbon content of 0.20 mass % or less, wherein the tailored blank includes an elongated future top plate portion, a future sidewall portion, and a future flange portion, a first steel sheet region that is configured by the first steel sheet is formed spanning part or all of a length direction of the future top plate portion, and a second steel sheet region that is configured by the second steel sheet is formed at the future flange portion to be joined by welding to another member, and wherein part or all of a length direction of the first steel sheet region is positioned within a length direction range of the second steel sheet region.

Tailored blank, tailored blank manufacturing method, stamped part, and stamped part manufacturing method

A flux-cored wire according to an aspect of the present invention includes: a steel sheath; and a flux filling the inside of the steel sheath, in which the flux contains 0.11% or more in total of a fluoride in terms of F-equivalent value, 4.30% to 7.50% of a Ti oxide in terms of TiOequivalent, 0.30% to 2.40% in total of an oxide in terms of mass %, and 0% to 0.60% in total of a carbonate in terms of mass %, the amount of a Ca oxide in terms of CaO is less than 0.20% in terms of mass %, the amount of CaFis less than 0.50%, a chemical composition of the flux-cored wire is within a predetermined range, a Z value is 2.00% or less, a V value is 5.0 to 27.0, and Ceq is 0.30% to 1.00% or less.

Flux-cored wire, manufacturing method of welded joint, and welded joint

The present invention provides an overlapping bonded structure in which breaking of a bonded section at holes formed during bonding can be prevented when an overlapping section formed by overlapping a plurality of meal plate members is bonded by means of a mechanical bonding means or a friction stir spot-welding means. This overlapping bonded structure, in which overlapping portions of a plurality of plate members are spot-welded at a plurality of bonded sections by means of a mechanical bonding means or a friction stir spot-welding means, and in the bonded sections a hole into which the mechanical bonding means is inserted or a hole formed during the spot-welding by the friction stir spot-welding means exists in at least one plate member, is characterized in that a cutout recess is formed between adjacent bonded sections, from an end portion of the overlapping section in the bonded-section direction, in the overlapping section of at least one of the plate sections, and when the inner diameter of the hole is K, an inside bottom portion of the cutout recess is formed at a position having a depth of K or greater from the end portion of the overlapping section.

Overlapping bonded structure

According to an aspect of the present invention, there is provided a flux-cored wire including a steel sheath and a flux that fills the steel sheath. The flux contains fluorides of which a total value &#x3b1; of F-equivalent values is 0.21% or more, oxides of which the total value &#x3b2; of amounts ranges from 0.30% to less than 3.50%, and carbonates of which a total value of amounts ranges from 0% to 3.50%. An amount of CaO ranges from 0% to less than 0.20%. An amount of iron powder ranges from 0% to less than 10.0%. A X-value is 5.0% or less. The amount of CaFis less than 0.50%. The amount of Ti oxides ranges from 0.10% to less than 2.50%. A ratio of &#x3b1; to &#x3b2; ranges from 0.10 to 4.00. A total value of amounts of MgCO, NaCO, and LiCOranges from 0% to 3.00%. Other chemical composition is within a predetermined range. Ceq ranges from 0.45% to 1.20%.

A structural member is provided that includes a steel sheet with a tensile strength of 980 MPa or higher overlying another metal plate and joined thereto by welding, where a break initiating near a welded portion is less likely to be produced. A structural member () includes: a first member (), the first member being a steel sheet with a tensile strength of 980 MPa or higher; a second member () overlying the first plate (), the second member being a metal plate; a plurality of welded portions (); a plurality of heat-affected zones () each formed to surround the corresponding one of the welded portions (), the heat-affected zones having a Vickers hardness lower than that of the first member by 50 HV or more. A pair of edge sections () of the first member () are provided between adjacent heat-affected zones (). The pair of edge sections () of the first member located between the adjacent heat-affected zones () extend to cross a line (LC) linking the adjacent welded portions ().

Structural member

A laser welded joint improving the tensile shear strength without causing an increase in the welding time and without using an expensive remote laser head, that is, a laser welded joint obtained by arranging metal sheets overlaid and welding them by a laser beam from the overlaid direction, wherein when a total thickness of the metal sheets welded overlaid is 't' (mm), the width of the weld metal at the joined interface is 0.6t1/3+0.14 (mm) or more.

Laser welded joint and method of production of same

An automotive framework memberincludes a first steel sheet, a second steel sheet, and a first weld metal partjoining an interface between the first steel sheetand the second steel sheet, in which tensile strength of the first steel sheetis 1.0 GPa or more and 1.6 GPa or less, tensile strength of the second steel sheetis 1.8 GPa or more and 2.5 GPa or less, the first steel sheetincludes a groove part, the second steel sheetis overlapped with the groove part, and a minimum Vickers hardness of a region within 4 mm of a periphery of the first weld metal partof the second steel sheetis 80% or more of a hardness of an outside of the region of the second steel sheet

Automotive framework member

According to an aspect of the present invention, there is provided a flux-cored wire including a steel sheath and a flux that fills the steel sheath. The flux contains fluorides of which a total value &#x3b1; of F-equivalent values is 0.21% or more, oxides of which the total value &#x3b2; of amounts ranges from 0.30% to 3.50%, and carbonates of which a total value of amounts ranges from 0% to 3.50%. An amount of CaO ranges from 0% to 0.20%. An amount of iron powder ranges from 0% to less than 10.0%. A Y-value is 5.0% or less. The amount of CaFis less than 0.50%. The amount of Ti oxides ranges from 0.10% to 2.50%. A ratio of &#x3b1; to &#x3b2; ranges from 0.10 to 4.00. A total value of amounts of MgCO, NaCO, and LiCOranges from 0% to 3.00%. A chemical composition excluding the fluorides, the oxides, the CaO, the carbonates, and the iron powder is within a predetermined range. Ceq ranges from 0.10% to 0.44%.

The present invention has as its object to inhibit fracture due to a HAZ softened part in substantially circular laser lap welding taking the place of resistance spot welding for joining a superposed plurality of steel sheets including a high strength steel sheet. To solve this problem, the inventors discovered lap welding comprising superposing a plurality of steel sheets and firing a laser to form a substantially circular laser weld (), which lap welding firing the laser in a straight line through an outer edge of the substantially circular laser weld () so as to form a hardened part () at the steel sheets and thereby suppressing fracture arising from the HAZ softened part.

Lap welding method, lap joint, production method of lap joint, and an automobile part

A method of welding an overlapped portion according to the present invention in which a plurality of steel sheet members are joined at an overlapped portion, and at least one of the plurality of steel sheet members contains martensite, includes: forming a spot-welded portion having a nugget in the overlapped portion; and emitting a laser beam to form a melted and solidified portion crossing an end of the nugget and located between the nugget and a position externally spaced apart from an end of the nugget by not less than 3 mm, this melted and solidified portion being formed in the steel sheet member containing the martensite so as to have a depth of not less than 50% of the thickness of the steel sheet member containing the martensite at a position externally spaced apart from the end of the nugget by 1 mm.

Method of welding overlapped portion, method of manufacturing overlap-welded member, overlap-welded member, and automotive part

A method of production of a welded structure by butt welding two steel sheets () by laser welding () while supplying assist gas () to a back surface of a melt pool (), whereby it is possible to prevent formation of a through hole in the melt part (), characterized in that a thickness of at least one steel sheet () of the two steel sheets () is 0.6 mm or less, the assist gas () is a mixed gas () containing 10 to 50 vol % of Ogas, and, when an Oconcentration in the mixed gas () is C (vol %), a flow rate L of mixed gas () (liter/min) satisfies(liter/min)&#x2212;C(vol %)&#xd7;1 (liter/min/vol %)&#x2264;L (liter/min)&#x3c;40 (liter/min).

Production method for welded structure

By superposing a plurality of steel sheets including a high tensile steel sheet and performing pulsation conduction by an inverter DC type spot welding power supply and controlling the conduction time of the current pulses, intervals of the current pulses, that is, conduction idle time, and weld current applied at the current pulses in a variable manner, the optimum weld conditions are obtained. For resistance spot welding of the hot stamped steel sheet, resistance spot welding with a minimum weld current of a second pulsation step higher than the maximum weld current at a first pulsation step is used to suppress the occurrence of outer spatter and inner spatter and secure a broad suitable current range even if using an inverter DC power supply.

Resistance spot welding method

Growing community of inventors

Tokyo, Japan

Hiroki Fujimoto