Jfe Steel Corporation

Ryo Ageba

Akinobu Ishiwatari

Jiro Hiramoto

A press forming tool is configured to form a press forming part including: a top portion; a side wall portion having a recessed portion in which a bottom edge is recessed toward the top portion; and a flange portion formed outward on a bottom edge of the side wall portion, the recessed portion including a first curved portion continuous with the bottom edge being a portion having a large wall depth, an inclined side portion continuous with the first curved portion, a second curved portion continuous with the inclined side portion, and a recessed side portion having a small wall depth, arranged in order from the bottom edge being a portion having a large wall depth, the flange portion being formed such that the flange portion formed in the first curved portion becomes a shrink flange while the flange portion formed in the second curved portion becomes a stretch flange.

Press forming tool and press forming method

A press forming method forms a press forming part including: a top portion having a convex and concave outer edge part where a convex outer edge part protruding outward in an in-plane direction and a concave outer edge part recessed inward in the in-plane direction are continuous to each other via a connecting outer edge part; and a flange portion continuously formed on the convex and concave outer edge part, and includes: forming a preformed part including a flange portion formed in the convex outer edge part and including a torsional shape portion having a torsional shape toward the concave outer edge part so as to be formed in the connecting outer edge part continuous from the flange portion; and forming the preformed part into a target shape by forming the torsional shape portion into the flange portion and forming the flange portion in the concave outer edge part.

Press forming method

A press forming tool is configured to form a press forming part including: a top portion having a convex and concave outer edge part; and a flange portion. The press forming tool includes: an upper die and a lower die; and a lower pad and an upper pad, which sandwich a blank in cooperation with the upper die and the lower die, in which, during an initial stage of forming, the flange portion is formed on the convex outer edge part, and a torsional shape portion having a torsional shape toward the concave outer edge part is formed continuously from the flange portion, and during a late stage of forming, the torsional shape portion is formed into the flange portion, and the flange portion is formed in the concave outer edge part so as to achieve formation of a target shape.

A press forming method for forming a press forming part includes: a first forming step of forming a preformed part, the preformed part including a side wall portion, a flange portion formed in a bottom edge being a portion having a large wall depth and a torsional shape portion formed in an inclined side portion continuous from the flange portion to reach a second curved portion; and a second forming step of further processing the preformed part formed in the first forming step, including processes of forming the torsional shape portion into the flange portion and forming the flange portion in the second curved portion continuous from the inclined side portion and in a recessed side portion having a small wall depth so as to achieve formation of a target shape.

Provided is a sheet material press forming method of press forming a formed part including a top portion with a protrusion having a blockage protrusive shape, the method including: preforming a high-strength steel sheet; and then forming it into a target shape without fractures or wrinkles, which is achieved by determining a shape in the preforming by press forming analysis according to the following steps: S1: the region of the protrusion having the target shape is discretized into two-dimensional elements and nodes for finite element analysis; and S2: the discretized portion are applied with internal stress in the normal directions of the two-dimensional elements from the inside of the discretized portion and deformed under the following conditions: (a) the two-dimensional elements are deformed within an elastic deformation range; and (b) adjacent ones of the two-dimensional elements have an angle therebetween which is free to change.

Sheet material press forming method

A press forming method for forming a press-formed product having no flange portion from a blank by performing a crash forming process while using a die and a punch, the press-formed product including at least a top portion and a side wall portion continued from the top portion via a connecting portion and being structured so that either all or a part of the side wall portion curves toward an outside of the press-formed product to form a convex shape in a planar view, the press forming method including forming the side wall portion while keeping a tip end portion of the blank in continuous contact with a side wall forming portion of the die and causing the die to impose no restraint on any part other than the tip end portion of the blank.

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Tokyo, Japan

Ryo Ageba