Kobe Steel, Ltd.

Toyota Jidosha Kabushiki Kaisha

Kabushiki Kaisha Kobe Seiko Sho (kobe Steel, Ltd.)

Kabushiki Kaisha Kobe Seiko Sho

Jiro Iwaya

Takayuki Yamano

Takayuki Kimura

Tatsuya Asai

Naoki Mizuta

Kenichi Watanabe

Junya Naitou

Kazuki Sakamoto

Yasuhiro Hayashida

Kiyoshi Nonomura

Kensuke Funada

Hiroshi Akamizu

Kazuhisa Maeda

Noriyuki Jimbo

Yoshiyuki Fukuyama

Toshiaki Funabiki

Koichi Kani

Akira Osumi

Yasuhiro Maeda

Hideto Katsuma

In a method for obtaining a hot-press-formed steel member, a steel sheet containing-mass % of C,-mass % of Si,-mass % of Si and Al in total, and-mass % of Mn is heated at a heating temperature of not less than the Actransformation point. The steel sheet is hot-press formed for one or more times. The starting temperature of the hot pressing is not more than the heating temperature but not less than the Ms point. The average cooling rate from (Ms point&#x2212;)&#xb0; C. to&#xb0; C. is&#xb0; C./s or less. The hot-press-formed steel member has high strength, high tensile elongation, high bendability, excellent deformation characteristics at the time of collision crush, and excellent delayed fracture resistance.

Method of manufacturing hot-press-formed steel member

A manufacturing method of a press-formed article includes arranging a member to be pressed between first and second dies, and relatively moving the first and second dies so as to approach each other, thereby press forming to a portion to be pressed so that a height of the portion to be pressed decreases. In the press forming step, while first bent portions in a pair each bent in a protruded shape toward the second die on the portion to be pressed are held by groove-shaped holding portions in a pair separated from each other on the second die, a second bent portion bent in a protruded shape from a position between the first bent portions toward the first die on the portion to be pressed is pressed and deformed by a pressing portion of the first die.

Manufacturing method of press-formed article, press-formed article, and press forming apparatus

A manufacturing method of press-formed article according to the present invention includes a step of placing a flat plate member between a first die and a second die, and a step of causing a first press portion and a second press portion approach each other, thereby pressing the flat plate member. In the step of placing, the flat plate member is placed so that a first main surface and a second main surface align with a vertical direction. In the step of pressing, the flat plate member is vertically pressed by causing the first press portion and the second press portion to approach each other in the vertical direction, and a thick portion is formed on the flat plate member by causing a part of a material of the flat plate member in the vertical direction to flow into a thickened portion-forming section formed on a first opposing surface.

Manufacturing method of press-formed article and press forming apparatus

A press forming process forms a blank, which is the material to be pressed, into a product having a predetermined shape including a continuous hat-shaped section in the longitudinal direction and a curved portion protruding toward the top surface side in the longitudinal direction. In the press forming process, an intermediate product which has an excess thickness portion formed at a part of the curved portion of the product and protruding higher than the top surface of the product is formed while constraining the portion of the intermediate product other than the excess thickness portion until the excess thickness portion projects in a direction opposite to the protrusion direction thereof, whereby the intermediate product is formed into a predetermined shape.

Press forming method

A press forming method forming an extended part by extension in a later forming period after deep drawing, the deep drawing process carried out with working at 100-250&#xb0; C., and the extension forming process carried out colder at less than 50&#xb0; C., whereby the extended part is formed by extension in a cup shaped low parts formed by deep drawing. Thus, press forming products containing formed elements can be deep drawing formed and extension formed at a high forming rate of 10 mm/sec or greater, which can assure high productivity. By making a steel plate temperature 100-350&#xb0; C. during press forming and by making the forming rate in the later forming period where extension forming is carried out slower than the forming rate in an earlier forming period where extension forming is not carried out, cracking of the extended part can be prevented and press forming limitations can be improved.

Press forming method for steel plate

Provided is a method for rapidly, surely, and easily identifying a factor of a shape defect of an artifact attributed to elastic recovery of deformation upon molding by using the numeric value simulation technique, thereby eliminating lowering of dimension accuracy. The method includes a step of calculating a stress distribution and distortion distribution working on an artifact before elastic recovery; a step of calculating a deformation amount &#x3b4;0 based on the elastic recovery of an evaluation point when the stress distribution is given to the artifact shape before the elastic recovery; a step of dividing the artifact shape into a plurality of regions and calculating a deformation amount &#x3b4;n based on the elastic recovery of the evaluation point when the stress distribution is given to each of the regions of the artifact shape before the elastic recovery; and a step of comparing the deformation amount &#x3b4;0 and the deformation amount &#x3b4;n and identifying a region where the difference between them is minimum as a main affect region, i.e., a stress distribution region which most affects the shape defect of the evaluation point before and after the elastic recovery.

Shape defect factor identification method, device, and program

A press forming method which can prevent a stretch-flange crack while using conventional press forming equipment at a time of press forming a formed member with flange includes steps of constructing a blank for press forming with a base body blank portion corresponding to flat base body of the formed member, and a concave flange blank portion formed by bending on a concave outer peripheral edge of the base body blank portion. The concave blank portion is constituted by a convex flange blank portion in which a stretch-flange deformation is generated, and an adjacent flange blank portion which is adjacent thereto. An outer peripheral edge of the convex flange blank portion is formed such that one end exists between two points on a profile line corresponding to an outer peripheral edge of the adjacent flange blank portion, the other end exists between two other points, and the one end and the other end are smoothly connected between the straight lines.

Press forming method of formed member with flange

In a first forming step, a metal sheet placed on, and held by a provisional horizontal flat forming portion of a first forming die part is bent along a provisional bend forming portion of the first forming die part to execute bent-forming such that two arch parts of the metal sheet, having respective protuberances oriented in directions opposite from each other, with protuberance surfaces being butted against a provisional inclined flat forming portion of a second forming die part, and a provisional inclined flat forming portion of the first forming die part, respectively, are coupled with each other, thereby obtaining a provisional formed member comprising a provisional inclined flat portion without any warpage, formed continuously from a provisional horizontal flat portion via a provisional bend, and a flange portion formed continuously from the provisional inclined flat portion so as to form a target angle. Subsequently, in a second forming step, the provisional formed member is formed into a target shape by causing the provisional bend to undergo deformation by bending back while bent-forming the provisional horizontal flat portion.

Bent-forming method

A die set for press forming a metal sheet is provided, which comprises: at least a punch; and a die, wherein a punch-die clearance CLcorresponding to a site to be formed immediately after the initial stage of press forming and a punch-die clearance CLcorresponding to a site to be formed in the initial stage of press forming are set so as to satisfy the following expressions (1) and (2), respectively:0.8&#xd7;1&#x2266;1.2&#xd7;&#x2003;&#x2003;(1)2&#x2267;1+&#x2003;&#x2003;(2)

Die set for press forming metal sheet and press forming method of metal sheet

A method in which engineers having no experience and technical storage can preliminarily easily and accurately predict an amount of dimensional accuracy defect which occurs at the time of press-forming a metal sheet before press-forming without having expertise such numerical value simulations and mathematics. In predicting an amount of dimensional accuracy defect at the time of press-forming a metal sheet, as a stress-strain relationship, an elastic-perfectly plastic solid model having a fixed stress value after being yielded is adopted and a value which is equal to or less than a tensile strength and exceeds a yield strength is used as an apparent yield strength.

Method for predicting an amount of dimensional accuracy defect at the time of press-forming metal sheet

Press die

Disclosed is a method for bending a metal plate comprising: a first forming step (A) for obtaining a first formed member having a bent portion; and a second forming step (B) for bending the first formed member in a direction of a bending direction of the bent portion so as to allow the bent portion of the first formed member to receive bending-back force. In bending a metal plate by a forming punch relatively moving to a forming die side, the metal plate is bent in an arch shape round the bent forming portion of the forming die. The angle &thgr;p formed between an inclined flat forming portion and a horizontal flat forming portion of the forming die is set to &thgr;p>0, so that the bent arch portion abuts with the inclined flat forming portion of the forming punch and the inclined flat portion of the forming die simultaneously for a certain period of time. This reduces the angle change defect of the bent portion of the formed portion, with no need of changing product shape or of preparing for a special forming die or a facility.

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Kakogawa, Japan

Jiro Iwaya