Nippon Steel Corporation

Takuya Oishi

Koichi Hamada

Tohru Yoshida

Takeshi Kawachi

Atsuo Koga

Ryuichi Nishimura

Shohei Yamazaki

A method for manufacturing a press-formed product suppresses occurrence of a forming defect such as a crack in a starting material during press forming, and also suppresses occurrence of problems when transferring a starting material during press forming. A manufacturing intermediate is formed by forming, in a flat-sheet shaped blank sheet, a planned outline portion including an undulating shape which is used for forming an outline of an outer circumferential portion of a press-formed product. The flat shape of the blank sheet is maintained in a region from the planned outline portion toward the center of the manufacturing intermediate, or an intermediate stretch-formed portion having a predetermined intermediate forming height is formed in the manufacturing intermediate in the region. A through-hole is formed by piercing a flat portion at which the flat shape is maintained or a stretch-formed-side top portion of the intermediate stretch-formed portion.

Method for manufacturing press-formed product

In an automobile hood, sufficient panel rigidity and dent resistance are secured while achieving weight reduction. Automobile hoodhas a panel, a reinforcing member, and a jointthat joins the paneland the reinforcing member. The reinforcing memberincludes a structure formed from a plurality of unitshaving a hexagonal annular shape disposed in a close-packed arrangement. Unithas a floor, inclined walland top plate. The flooris adjacent to the panel. Top plateand panelare separated from each other. The inclined wallis arranged between the floorand the top plate. A hexagonal annular first ridge lineof the unitis located between the inclined walland the floor. A length Lof one side of the first ridge lineis 40-75 mm.

Automobile hood

In an automobile hood, sufficient panel rigidity and dent resistance of a panel are secured while achieving weight reduction. An automobile hood having panel, reinforcing member and joint that joins the panel and the reinforcing member such that the reinforcing member includes a structure formed from a plurality of units having hexagonal annular shape disposed in a close-packed arrangement. Floor of the unit has an annular end part. All of annular end part is located between first circle and second circle wherein first circle is inscribed within a first ridge line overlapping with an outer end part of the floor. Second circle is concentric with first circle and has a radius that is 60% of a radius of the first circle. Width of upper face of floor is 2 mm or more over the entire area of the annular end part in the circumferential direction of the annular end part.

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Tokyo, Japan

Takuya Oishi