Nippon Steel Corporation

Nippon Steel Sumitomo Metal Corporation

Osaka University

Nippon Steel & Sumitomo Metal Corportion

Masanori Yasuyama

Yoshiaki Nakazawa

Tohru Okada

Hiroki Fujimoto

Hitomi Nishibata

Kenichiro Otsuka

Yasuhiro Ito

Tasuku Zeniya

Chisato Yoshinaga

Yujiro Tatsumi

Masatoshi Tokunaga

Gen Murayama

Teruki Sakamoto

Manabu Fukumoto

Masahiro Saito

Toshiya Suzuki

Masahiro Nakata

Hiroyuki Kawata

Koichi Hamada

Kunio Hayashi

Ryuichi Nishimura

Yasunobu Miyazaki

Satoshi Hirose

Hidetoshi Fujii

Takumi Tamezane

Yoshiaki Morisada

Atsuo Koga

Takashi Imamura

Yasunori Sawa

Masahito Tasaka

Hitoshi Sakuma

Yasuhiro Aoki

Ayaka Musha

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

This spot welded joint includes a first steel sheet having tensile strength of 1100 MPa or higher and hard martensitic structure as main structure, a second steel sheet stacked on the first steel sheet, a nugget having diameter D at an interface between the first and second steel sheets and formed between the first and second steel sheets, and a hardness control region occupying, in a cross section of the first steel sheet in sheet thickness direction that passes a nugget center, a region that is the first steel sheet in sheet thickness direction and is from 0.5×D to 1.0×D from the nugget center in sheet surface direction and in which difference between maximum value and minimum value in hardness in the region is 80 HV or less, and the maximum hardness value in the region is lower than the maximum hardness value of the first steel sheet.

Spot welded joint, vehicle framework component provided with spot welded joint, and method of manufacturing spot welded joint

There is provided a resistance spot welding apparatus including a first rod-shaped electrode body, second rod-shaped electrode body, first ring-shaped member, second ring-shaped member, first elastic body, and second elastic body. The first rod-shaped electrode body and second rod-shaped electrode body are arranged facing each other, the first rod-shaped electrode body is inserted into a through hole of the first ring-shaped member, the first elastic body is connected to an opposite side of first ring-shaped member to second rod-shaped electrode body side, the first rod-shaped electrode body and first ring-shaped member are not electrically connected to each other, the second rod-shaped electrode body is inserted into a through hole of the second ring-shaped member, the second elastic body is connected to an opposite side of second ring-shaped member to first rod-shaped electrode body side, and the second rod-shaped electrode body and second ring-shaped member are not electrically connected each other.

Resistance spot welding apparatus and method for manufacturing a welded structure

A linear friction welding method capable of accurately controlling a welding temperature and capable of lowering the welding temperature is provided. The present invention is a linear friction welding method comprising: a first step of forming a welded interface by bringing one member into contact with the other member; a second step of repeatedly sliding one member and the other member on the same locus and discharging flash from the welded interface in a state where pressure is applied substantially perpendicularly to the welded interface; and a third step of forming a welded surface by stopping the sliding and setting the pressure to be not less than the yield stress and not more than the tensile strength of one member and/or the other member at a desired welding temperature.

Linear friction welding method

The present invention provides a spot welding method for a member to be welded constituted of a plurality of steel sheets that are overlapped with each other at at least a welding zone, in which at least an overlapped face of at least one of the plurality of steel sheets at the welding zone is coated with zinc plating, a total sheet thickness t (mm) of the plurality of steel sheets is 1.35 mm or more, a squeeze time St (seconds) from the time when welding electrodes are brought into contact with the member to be welded to the time when electric current flow for welding starts satisfies '0.020&#x2264;St', and a hold time Ht( seconds) after welding from the time when electric current flow for welding between the welding electrodes ends to the time when the welding electrodes and the member to be welded are brought out of contact satisfies '0.015t+0.020&#x2264;Ht'.

Spot welding method

Provided is a spot welding machine able to perform spot welding in which the desired nugget size is formed while suppressing spatter even if the strengths or thicknesses of the metal sheets change, the machine comprising: a pair of electrode tips, a pair of pressing members arranged around the tips, a first power supply, first and second drive mechanisms, and a pressing force control part, wherein the tips and the pressing members are respectively arranged facing each other so as to be able to sandwich a set of sheets between them, the first drive mechanisms give pressing forces pressing the tips against the sheets, the second drive mechanisms give pressing forces pressing the pressing members against the sheets, and the control part independently controls the pressing forces given by the first and second drive mechanisms.

Spot welding electrode having movable pressing members and spot welding method using same

A control arm includes a pair of mounting portions provided separately from each other and a main body portion extending in a X-direction and connecting the pair of mounting portions. At a cross-section perpendicular to the X-direction at a position along the X-direction, the main body portion includes: a first V-shaped member having a first apex and opening from the first apex in a V-shape toward one side in a Y-direction, and a second V-shaped member having a second apex and opening from the second apex in a V-shape toward the other side in the Y-direction. At the cross-section, the first apex and the second apex are joined. At a cross-section perpendicular to the X-direction at the center position of the main body portion in the X-direction, an opening angle of the first V-shaped member and an opening angle of the second V-shaped member are each no more than 150&#xb0;.

Control arm

A press-formed product is shaped by press-working from a tailored blank made up of a plurality of metal sheets butt-welded together. The press-formed product includes a flange section, and an arc-shaped area which is an area of the flange section which is formed by stretch flange deformation, and in which an inner peripheral edge is open. A weld line of the tailored blank intersects with the inner peripheral edge and an outer peripheral edge of the arc-shaped area. An angle &#x3b8; formed by the weld line and a maximum principal strain direction of the stretch flange deformation is 17 to 84&#xb0;.

Press-formed product and method for designing the same

A method of joining a metal and a plastic member, a method of joining a CFRP member and a plastic member, a method of joining a metal and a CFRP member through a plastic member, in particular a method of joining members able to join members by a faster joining speed and able to give a joined member excellent in joining strength are provided. A method of joining a metal and a plastic member by overlaying a metal and a plastic member and joining them by firing a laser beam from the plastic member side, comprising overlaying the plastic member and glass through which the laser beam will pass on the metal in that order and firing the laser beam from the plastic member side through the glass at a joining location where the metal and the plastic member are overlaid to join them by a joining speed of 0.5 m to 5.0 m/min.

Method of joining metal, plastic member, and carbon fiber reinforced plastic member

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 brazed joint having excellent tensile strength (TSS and CTS) and a method of production of the same are provided. A sheet combinationcomprised of steel sheetsbetween which a brazing filler metalis clamped is heated at a temperature of the Ac3 point of the steel sheet (matrix material) or more. The Ar3 point of the regions near the brazing filler metal at the steel sheets is made higher than the Ar3 point of the steel sheets (matrix material), then the quenching start temperature X is made a temperature of the Ar3 point of the steel sheet (matrix material) or less and hot stamping is performed to produce a brazed joint.

Method of production of brazed joint and such a brazed joint

A joining structure of the invention includes a first metal sheet and a pair of second metal sheets. Each of the pair of second metal sheets is overlapped on the first metal sheet in a state where an end surface of one of the second metal sheets and an end surface of the other second metal sheet face each other, and the end surfaces that face each other are integrally joined to the first metal sheet by means of a single mass of melted metal.

Joining structure

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

A overlapped bodycomprising steel platesandand satisfying (TS&#xd7;t+TS&#xd7;t)/(t+t)&#x2265;440 is energized while being sandwiched and pressed by a pair of electrodesandto form a molten poolat a steel plate interfaceand thereby to join the steel platesand. TSrepresents the tensile strength (MPa) of the steel plate, trepresents the thickness (mm) of the steel plateTSrepresents the tensile strength (MPa) of the steel plate, and trepresents the thickness (mm) of the steel plate. An energization pointis formed at the steel plate interface, and spot welding is performed such that the molten poolis formed at a position at a horizontal distance W of 20 mm or less from the energization point.

Resistance spot welding method and welded structure

An overlapped bodyincludes at least three steel platesandand in which at least one steel plate interfacehas a contact resistance different from the contact resistance of another steel plate interface. A molten pool is formed at the steel plate interfaces so as to join the steel platesand, and an energization pointis formed at the steel plate interfacehaving the largest contact resistance. Initial spot welding is performed under a condition in which a branch current is generated in the energization pointso as to form the molten pool. By doing so, it makes it difficult to generate the expulsion and surface flash at the steel plate interface where resistive heating is large and form the molten pool having a sufficiently large size at the steel plate interface where resistive heating is small.

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Tokyo, Japan

Masanori Yasuyama