Jfe Steel Corporation

Nkk Corporation

Jfe Corporation

Jfc Steel Corporation

Jfs Steel Corporation

Yuji Yamasaki

Toyohisa Shinmiya

Kazuhiko Higai

Yusuke Vincent Fujii

Hiroto Miyake

Eiji Iizuka

Kento Fujii

Katsuhiro Ochi

Takeshi Fujita

Kinya Nakagawa

Fusato Kitano

Takaaki Hira

Yasuhiro Kishigami

Shunsuke Tobita

Hiroshi Matsuda

Yasunobu Nagataki

Kohei Hasegawa

Reiko Sugihara

Yoshihiro Hosoya

Yoshikiyo Tamai

Toshiaki Urabe

Yoshinori Yomura

Takayuki Futatsuka

Masaya Morita

Toru Inazumi

Moriaki Ono

Masahisa Fujikake

Katsumi Nakajima

Masayoshi Kurihara

Yuta Kariyazaki

Kaoru Sato

Masaaki Yamashita

Masaki Tada

Kentaro Sato

Satoru Ando

Yoichiro Yamanaka

Junichi Inagaki

Masayasu Ueno

Yoshiharu Sugimoto

Tsuyoshi Shiozaki

Yukio Kimura

Eiichi Shiraishi

Yutaka Mihara

Hisato Noro

Takashi Iwama

Yasuhiro Sodani

Yusuke Fujii

Akihide Yoshitake

Kayo Tokieda

Shogo Tomita

Yukiko Hata

Youiti Komatu

Kazunari Yoshitomi

A pressed component manufacturing method wherein, in press forming a metal sheet into a final component shape through two or more press steps, the inflow amount of the required material is determined based on the increase in the cross-sectional line length of the shape with respect to the line length before forming when the metal sheet is press formed by a single press step, the determined amount is distributed to each step, and a preformed shape after press forming based on the distributed inflow amount. As the cross section, a line orthogonal to a direction in which the material flows when the metal sheet is drawn is set, and a plurality of cross sections is set which is individually cut by each of planes orthogonal to the line and extending in a direction along the sheet thickness direction of the metal sheet before forming.

Pressed component manufacturing method, die designing method, die shape designing device, and die

A pressing technology for reducing tensile residual stress generated on a sheared edge face of a metal sheet after press forming in order to prevent occurrence of a delayed fracture on the sheared edge face. A pressed component manufacturing method for manufacturing a pressed component by press-forming a metal sheet having a sheared edge face includes a first press forming step in which it is estimated that tensile residual stress is generated in a direction along the sheared edge on a portion of the sheared edge face of the metal sheet after die release, in which the method includes, as a subsequent step to the first press forming step, a tensile residual stress relaxation step of bulging, in the sheet thickness direction, a region that includes at least a site on a sheared edge face where it is estimated that the tensile residual stress is generated.

Pressed component manufacturing method

A shearing die for preventing damage of a die tool in shearing of a super-high-tension steel sheet and a press-forming method using the same. The shearing die for shearing a metal sheet in a direction intersecting a first-sheared edge of the metal sheet in press-working including a plurality of shearing processes to produce a formed article from the metal sheet by press-forming, in which the shearing die comprises a fitting part that can detach a shearing blade in the vicinity of a region coming in contact with an end of the first-sheared edge.

Shearing die and press-forming method

Warpage or torsion in a longitudinal direction is suppressed when an elongated curved component is manufactured by press forming. A method for manufacturing a pressed component includes a first step of press forming a metal sheet in a desired component shape using a first die, and a second step of press forming a formed product using a second die after the first step. In the second step, a cross section of a bent part and a vertical wall part are controlled to be opened depending on warpage at longitudinal end portions of the component by elastic recovery due to release from the first die, thereby suppressing the warpage.

Method for manufacturing pressed component, and shape correction die

A method for manufacturing a press-formed product includes a blanking step of blanking from a sheet-shaped material into a shape in which an excess material portion is added to the contour outline of a developed shape of the press-formed product, a first pressing step of folding the excess material portion to form straight sides into an intermediate formed product with a bent flange portion, a second pressing step of performing press forming including bulging in which the bulging portion is provided on the intermediate formed product, and a trimming step of trimming the excess material portion. A blank material includes excess material portion to be folded to form straight sides circumscribed around or spaced apart from a contour outline of a developed shape of the press-formed product, and an intermediate formed product includes excess material portion including a bent flange portion folded to form straight sides.

Press-forming method, blank member for sheet-shaped material, intermediate formed product, method for manufacturing press-formed product, and press-formed product

A technology for evaluating forming allowance for a bending crack at a sheared end face of the press-formed component from shape information of an actual component. The method includes applying press forming including bending deformation to a metal sheet being sheared to manufacture a press-formed component, evaluating forming allowance for a bending crack at a sheared end face being an end face subjected to the shearing. A crack index value for evaluating the bending crack at the sheared end face of the press-formed component is obtained from a bend outer side strain at or near the sheared end face acquired on a basis of a component shape of the press-formed component and a press die bend radius at a portion forming the sheared end face in a press die used in the press forming, and the forming allowance for the bending crack is evaluated by the obtained crack index value.

Method for evaluating bending crack, system for evaluating bending crack, and method for manufacturing press-formed component

A method includes two or more reference strain gradient information being a relationship between the strain at the hole edge and a strain gradient along a radial direction. Hole expansion forming is performed on the evaluation metal sheet under the same forming conditions as respective forming conditions corresponding to at least two pieces of the reference strain gradient information to obtain at least two limit hole expansion ratios at a hole expansion limit of the evaluation metal sheet. A formable region of the evaluation metal sheet is obtained from the at least two pieces of the reference strain gradient information and the obtained at least two limit hole expansion ratios at the hole expansion limit. Stretch flange cracking at the sheared end face of the evaluation metal sheet is evaluated by the obtained formable region.

Stretch flange crack evaluation method, metal sheet selection method, press die design method, component shape design method, and pressed component manufacturing method

A material is press formed into a component shape including a top sheet portion including a curved outer peripheral edge portion curved in such a manner as to be recessed inward, a vertical wall portion, and a flange portion. When a lower die and a pad sandwich a sandwiching region that is a region including at least a part of a region corresponding to the top sheet portion, an upper die is moved in a pressing direction to perform bending while moving the sandwiched material to the vertical wall portion side. A surface of the lower die that sandwiches the sandwiching region is provided with one or more ridgelines for forming bends. The ridgelines are set at positions such that, when the bending is complete, the position of the top sheet portion is located on the vertical wall portion side rather than the positions of the ridgelines.

Method for manufacturing pressed component

An object to provide a press-forming method that can efficiently suppress springback and easily specify a position where a springback reduction effect by rigidity improvement is large, and the press-forming method used in producing a press-formed product having a predetermined shape by press-forming a sheet material, the method including: a first process that repeatedly performs a springback analysis, while changing a position to be restricted, to specify a position where a springback reduction effect by rigidity improvement is large; a second process that performs a rigidity improvement measure on a position of the sheet material corresponding to the position of the formed-product model specified in the first process; and a third process that produces the press-formed product by press-forming the sheet material on which the rigidity improvement measure has been performed.

Press forming method, rigidity-improvement-position specifying method, press forming system, and press-formed product

A press forming technology capable of reducing forming defects in a formed component having a hat-shaped cross-sectional shape and including a shape curved to protrude toward a flange portion in a side view. The technology includes a first forming step of press forming a metal sheet into an intermediate formed product that includes a wavy shape including uneven shapes continuous along a longitudinal direction in vertical wall portion and flange portion forming positions, an amplitude of the uneven shapes in a sheet thickness direction increasing toward a position corresponding to a boundary between the portions, and a second forming step of performing bending on the intermediate formed product. A longitudinal line length at the position corresponding to the boundary between the portions in the intermediate formed product is set to coincide with or approach a longitudinal line length at the boundary between the portions in the press-formed component shape.

Production method for pressed components, press forming device, and metal sheet for press forming

A method includes press forming a metal sheet into an intermediate formed product bent out of a plane and forming into a desired press-formed component shape. In a region to be a flange portion, an angle to be bent out of the plane is equal to or less than an angle formed by the flange portion at the curved portion in the press-formed component shape. The projection portion has a largest projection height at the center portion in the longitudinal direction of the region to be the curved portion as seen in the side view, and a longitudinal length of a region to be the top sheet portion is set to coincide with or approach a longitudinal length of the top sheet portion in the press-formed component shape.

There are provided an evaluation method and a prediction method for a technology to be reflected in a press die designing method. A deformation limit evaluation method includes evaluating the deformation limit on a sheared surface of a metal sheet in press-forming the sheared metal sheet. The deformation limit is evaluated and a crack in the sheared surface is predicted based on the relationship between an index value determined from two surface strain distribution gradients of a surface strain distribution gradient in a sheet thickness direction in the sheared surface and a surface strain distribution gradient in a bending ridge line direction by bending in a direction away from the sheared surface at an evaluation position among distributions of strains generated near the boundary between a bending outside surface and the sheared surface of the metal sheet to be bent and a tension generated in the sheared surface.

Deformation limit evaluation method for sheared surface of metal sheet, crack prediction method, and press die designing method

To prevent a crack from occurring on a sheared end face due to press forming, a technology is provided for evaluating and predicting a crack limit of the sheared end face of a metal sheet and determining press forming conditions. In a deformation limit evaluation method for, when deforming by press forming a metal sheet subjected to shearing, evaluating a deformation limit of the sheared end face of the metal sheet, the deformation limit is evaluated by an index value obtained from two stress gradients at an evaluation position among stress distributions occurring in the vicinity of the sheared end face of the metal sheet due to the press forming, which gradients are a stress gradient in a sheet thickness direction and a stress gradient in a direction away from the sheared end face.

Press die designing method using an index value obtained from two stress gradients in sheet thickness direction and gradient of surface stress distribution in direction

A press formed product is disclosed. A method for manufacturing the press formed product is a method for manufacturing the press formed product including applying press processing including stretch flange forming to a single metal sheet of one sheet material after performing shearing processing of the metal sheet to manufacture the press formed product. When a region where a stretch flange crack is estimated to be likely to occur when the single metal sheet is press formed by the press processing is set as a stretch flange crack region, the press processing is applied after heating and cooling the end surface of the metal sheet positioned in the stretch flange crack region and at least the end surface in the end surface and the vicinity thereof in the single metal sheet after the shearing processing.

Method for manufacturing press formed product

A metal sheet for press forming has a shape such that a boundary position between the region corresponding to the curved portion and an other region in the region corresponding to a curved portion is rotationally displaced in-plane around a rotational center set at a position on a curved recessed side rather than a position corresponding to a ridge line between a top sheet portion and a vertical wall portion on the curved recessed side, in a direction in which a line length of an outer edge of a position to be formed into the flange portion on a curved protruding side in the region corresponding to a curved portion approaches a line length of an outer edge of the flange portion on the curved protruding side in the press-formed component shape.

Metal sheet for press forming, press forming device, and production method for pressed component

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Tokyo, Japan

Yuji Yamasaki