Nippon Steel Corporation

Nippon Steel Sumitomo Metal Corporation

Shigeru Yonemura

Tohru Yoshida

Akihiro Uenishi

Takuya Kuwayama

Takashi Yasutomi

Jun Nitta

Takashi Ariga

Naoki Maruyama

Nobuo Yoshikawa

Satoshi Shirakami

Noriyuki Suzuki

Masahiro Saito

Hiroyuki Kawata

Tatsuo Yokoi

Hiroshi Yoshida

Toshiyuki Niwa

Akinobu Murasato

Shunji Hiwatashi

Akinobu Minami

Kazuya Ootsuka

Shin Toyokawa

Koichi Sato

Yasuhiro Ito

Masafumi Azuma

Yasuharu Tanaka

Natsuko Sugiura

Yasunobu Miyazaki

Satoshi Hirose

Takeshi Yasui

Kazuhiko Honda

Masahiko Yoshino

Takashi Matsuno

Yasunori Sawa

Mai Nagano

Yasuaki Naito

Akira Egami

Kohki Nakamura

A shearing method of a plate-shaped workpiece for applying a shear force in a thickness direction of the plate-shaped workpiece includes: a step for starting applying the shear force on the workpiece with a clearance between action points in a surface direction orthogonal to the thickness direction of the workpiece; a step for applying the shear force after the start of applying the shear force until a fractured surface is created in the workpiece; and a step for increasing the clearance depending on a deformation of the workpiece in the thickness direction after starting applying the shear force until the fractured surface is created in the workpiece.

Shearing method, shearing device, and shearing facility

A shock absorbing member which can increase impact absorption energy and also enables thinning of a steel sheet that is a starting material, a method for producing the shock absorbing member, and a method for producing a steel sheet for cold plastic working are provided. The shock absorbing member includes a ridge portion formed in a curved shape as viewed from a longitudinal direction, and a wall portion extending from the ridge portion. In the wall portion, a ratio σ/τbetween a tensile stress σwhen an elongation in a tensile test is 5% and a shear stress τwhen a shear strain in a shear test is 5√3% is 1.70 or less, or a ratio σ/τbetween a tensile stress σwhen an elongation in a tensile test is 10% and a shear stress τwhen a shear strain in a shear test is 10√3% is 1.70 or less.

Shock absorbing member, method for producing shock absorbing member, and method for producing steel sheet for cold plastic working

This structural member is manufactured using a structural member manufacturing device including a first clamping part having a first lower clamping member and a second upper clamping member disposed to face each other and capable of being opened and closed; a second clamping part having a third lower clamping member and a fourth upper clamping member disposed to face each other corresponding to the first lower clamping member and the second upper clamping member and capable of being opened and closed; and clamping part driver for allowing the first clamping part and the second clamping part to be relatively separated from each other while causing a position in an X-axis direction and a position in a Z-axis direction to correspond to each other.

Structural member, structural member manufacturing method, and structural member manufacturing device

In a method for producing an outer panel having a character line, a punch includes a projecting portion for forming a bent surface of the character line at a punch top portion, and a punch shoulder R portion. A contact pressure applied to a blank by at least one of the projecting portion and the punch shoulder R portion is higher than a contact pressure applied to the blank by a remaining portion of the punch which excludes the projecting portion and the punch shoulder R portion. A static friction coefficient of a first portion of the punch which includes at least one of the projecting portion and the punch shoulder R portion with respect to the blank is larger than a static friction coefficient of a second portion of the punch which excludes the first portion with respect to the blank.

Method and apparatus for producing outer panel having character line

There is provided a hole widening method including a preparing process of preparing a forming tool which has a diameter-increasing portion increasing in diameter from a front end side toward a rear end side and a line-shaped projection formed to protrude outward from a surface of the diameter-increasing portion, and a workpiece in which a pilot hole is formed; and a hole widening process of successively widening the pilot hole by pushing the forming tool into the pilot hole such that the line-shaped projection of the forming tool comes into point contact with a part of a circumferential edge portion of the pilot hole in the workpiece two times or more, and forming a stretched flange.

Hole widening method, forming tool, and formed product

In a breaking prediction method of predicting a breaking portion of a component, which is obtained by forming a metal sheet, by using a finite element method, the breaking portion is easily and reliably extracted. This breaking prediction method includes a first step of performing forming analysis by using a finite element method in each of a case where the metal sheet is divided on the basis of a first mesh coarseness and a case where the metal sheet is divided on the basis of a second mesh coarseness which is coarser than the first mesh coarseness, a second step of obtaining a maximum main stress for each mesh in each of the case of the first mesh coarseness and the case of the second mesh coarseness, and a third step of obtaining a difference value between the maximum main stress in the case of the first mesh coarseness and the maximum main stress in the case of the second mesh coarseness in each portion of the component, and extracting a portion in the case of the first mesh coarseness, which corresponds to a portion in which the difference value is larger than a predetermined value, as the breaking portion.

Breaking prediction method, program, recording medium, and arithmetic processing device

The present invention provides a method for shear processing whereby a sheared surface having a small residual stress and excellent surface properties is formed and the service life of a punch is prolonged in a shear processing for shearing, by a shear line that crosses a weld zone, a workpiece with a large thickness of level difference of a weld zone and/or obtained by welding together a steel sheet having a strength of 1000 MPa or more and another steel sheet. The shearing for shear processing method according to the present invention is a method for shearing a workpiece having a weld zone using a punch and a die, the method characterized in that two protrusions are provided to a cutting edge of the punch, all or part of the weld zone of the workpiece is flanked from the two sides by the two protrusions, and the workpiece is sheared by a shear line that crosses the weld zone.

Method for shear processing

A hot rolled steel sheet having a chemical composition consisting of, in mass %, C: 0.020-0.180%, Si: 0.05-1.70%, Mn: 0.50-2.50%, Al: 0.010-1.000%, N: 0.0060%, P&#x2264;0.050%, S&#x2264;0.005%, Ti: 0-0.150%, Nb: 0-0.100%, V: 0-0.300%, Cu: 0-2.00%, Ni: 0-2.00%, Cr: 0-2.00%, Mo: 0-1.00%, B: 0-0.0100%, Mg: 0-0.0100%, Ca: 0-0.0100%, REM: 0-0.1000%, Zr: 0-1.000%, Co: 0-1.000%, Zn: 0-1.000%, W: 0-1.000%, the balance: Fe and impurities, wherein a metal microstructure includes, in area %, at a position &#xbc; W or &#xbe; W from an end face of the steel sheet and &#xbc; t or &#xbe; t from a surface, martensite: more than 2%-10%, retained austenite &#x3c;2%, bainite 40%, pearlite 2%, the balance: ferrite, an average circle-equivalent diameter of a metallic phase constituted of martensite/retained austenite is 1.0-5.0 &#x3bc;m, an average of minimum distances between adjacent metallic phases is 3 &#x3bc;m or more, and a standard deviation of nano hardness is 2.0 GPa or less.

Hot rolled steel sheet

A hot rolled steel sheet including a chemical composition consisting of, in mass %, C: 0.07-0.22%, Si: 1.00-3.20%, Mn: 0.80-2.20%, Al: 0.010-1.000%, N&#x2264;0.0060%, P&#x2264;0.050%, S&#x2264;0.005%, Ti: 0-0.150%, Nb: 0-0.100%, V: 0-0.300%, Cu: 0-2.00%, Ni: 0-2.00%, Cr: 0-2.00%, Mo: 0-1.00%, B: 0-0.0100%, Mg: 0-0.0100%, Ca: 0-0.0100%, REM: 0-0.1000%, Zr: 0-1.000%, Co: 0-1.000%, Zn: 0-1.000%, W: 0-1.000%, Sn: 0-0.050%, the balance: Fe and impurities, wherein a metal microstructure includes, in area %, at a position &#xbc; W or &#xbe; W from an end face of the steel sheet and &#xbc; t or &#xbe; t from a surface, retained austenite: more than 2%-10%, martensite &#x2264;2%, bainite: 10-70%, pearlite &#x2264;2%, the balance: ferrite, an average circle-equivalent diameter of a metallic phase constituted of retained austenite/martensite is 1.0 to 5.0 &#x3bc;m, an average of minimum distances between adjacent metallic phases is 3 &#x3bc;m or more, and a standard deviation of nano hardness is 2.5 GPa or less.

[Object] To enable flexible molding of a punch-nose in press working for obtaining a molded product including a U-shaped portion in a cross-section. [Solution] Provided is a press-working apparatus configured to provide a molded product by performing press working on a work, the molded product including, in a cross-section, a U-shaped portion including a bottom, a wall, and a punch-nose between the bottom and the wall, the press-working apparatus including: a die in which a recessed portion to receive the U-shaped portion is formed; a first punch that sandwiches a central area of the bottom with a bottom surface of the recessed portion; and a second punch that is pushed into the recessed portion later than the first punch, to restrain the wall between the second punch and a side surface of the recessed portion, and sandwich the work with the bottom surface to mold a peripheral area of the bottom and the punch-nose. A sandwiching width of the first punch that sandwiches the central area of the bottom and a setback amount of the second punch from the first punch in a push-in direction are set on the basis of a target sheet thickness of the punch-nose.

Press-working apparatus, press-working method, and press-molded product

A laser welded joint has weld metal provided between a plurality of steel sheets. A chemical composition of the weld metal has predetermined components, and average hardness of the weld metal is 350 to 540 in Vickers hardness. In the weld metal, distribution density of porosities having a diameter of 2 &#x3bc;m to 50 &#x3bc;m is equal to or less than 5.0 pieces/mm. In the weld metal, distribution density of oxide inclusions having a diameter of 3 &#x3bc;m or more is 0.1 to 8.0 pieces/mm.

Laser welded joint, vehicle component, manufacturing method of laser welded joint, and manufacturing method of vehicle component

A method for manufacturing a press-formed product includes: a first step of preparing a long material having a bending portion; and a second step of decreasing curvature of the bending portion while restricting both ends of the long material in a longitudinal direction.

Method for manufacturing press-formed product, device for manufacturing press-formed product, mandrel, and press-formed product

Provided is a steel material shearing method that enables highly productive and low-cost production of a steel material with a sheared surface having excellent hydrogen embrittlement resistance, fatigue strength, and stretch flangeability. The shearing method comprises making a clearance between a die and a punch 5 to 80% of a sheet thickness of a workpiece, shearing the workpiece using the punch, and, by utilizing a punched material punched out by the punch, pressing an end face of the punched out material against the sheared surface of the worked material on the die to produce a steel sheet with a sheared edge having excellent hydrogen embrittlement resistance and fatigue strength.

Shearing method

Provided is a shearing method which can produce a worked material having a sheared edge excellent in surface perpendicularity and surface properties with a good productivity while suppressing tool wear and damage. The method comprises a first shearing step of placing a first blank having first and second surfaces on a first die so that said second surface is arranged on said first die side, and shearing said first blank from said first surface toward said second surface in a sheet thickness direction of said first blank by a first punch arranged at said first surface side to obtain a first punched out material and first worked material; and a second shearing step of placing a second blank and (x) using said first punched out material as a second punch, (y) using said first worked material as a second die, or both thereof.

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Tokyo, Japan

Shigeru Yonemura