Nippon Steel Corporation

Ryo Tabata

Takeshi Kawachi

Yasuhiro Ito

Masahiro Nakata

Masahiro Saito

Koichi Hamada

Kenichiro Otsuka

Masafumi Azuma

Jun Nitta

Takeshi Toyoda

Takashi Yasutomi

Ryo Urushibata

Kohei Nakada

Ryoma Kato

Yuki Kitahara

The present invention has as its technical problem to provide a punching method able to stably secure a stretch-flangeability equal to or greater than the case of using a punch having a flat blade at its bottom surface. The punching method of the present invention is a method of punching a metal sheet using a punching and shearing device provided with a punch having an upper blade having a horizontal part with respect to the cutting line in part and having parts other than the horizontal part comprised of inclined parts and a die having a lower blade wherein the upper blade used for the punching process has a shape where the inclined parts first contact the metal sheet at the time of a punching process.

Method for producing blank, method for producing press-formed part, method for judging shape, program for judging shape, apparatus for producing blank, and blank

The present disclosure provides a structural member comprising an edge portion Tand an edge portion Topposing the edge portion Tin plan view in height direction (Z axis direction); when an axis direction connecting the edge portion Tand the edge portion Tis regarded as an X axis direction, the structural member includes, along the X axis direction, a region A including the edge portion T, and a region B located on the edge portion Tside than the region A and including the edge portion T; in a cross-section perpendicular to the X axis direction, the region A includes a closed cross-section portion A whose outer rim shape is one closed cross-section A; and the region B includes a closed cross-section portion B satisfying a predetermined (i) or (ii).

Structural member

A structural part includes a part body and a cylindrical bush. The part body includes a through-hole and a cylindrical flange part provided in the periphery of the through-hole. The bush is inserted into the through-hole and the flange part. When seen in a cross section including a central axis of the bush, the flange part has a height difference between a first part that contacts the bush on one side in a direction perpendicular to the central axis and a second part that contacts the bush on the other side.

Structural part

A suspension arm includes a main body. The main body includes a curved portion curved along a longitudinal direction and has a closed section. The main body includes an inner side wall, an outer side wall, a first side wall, and a second side wall. The inner side wall corresponds to an inner side of a curve of the curved portion. The outer side wall corresponds to an outer side of the curve of the curved portion. A thickness of the inner side wall is larger than a thickness of the outer side wall. In sectional view of the main body perpendicular to the longitudinal direction, each of a length of the first side wall and a length of the second side wall is longer than each of a length of the inner side wall and a length of the outer side wall.

Suspension arm

As a burring processed member able to suppress the formation of fatigue cracks in a burring part, one having a structure satisfying the following relations (1) to (3) is disclosed: 3≤Ra≤100 . . . (1), 3.0<h . . . (2), 24+r−[TS/(40+0.28×Ra)]<h . . . (3), where, 'Ra' is an arithmetic mean roughness (μm) of the burring end face, “h” is a height (mm) from the first surface to the burring end face, “r” is a radius of curvature (mm) of the curved wall part, and “TS” is the tensile strength (MPa) of the sheet-shaped part.

Burring processed member

A strength flanging method which improves the method of stretch flanging by press forming so as to disperse strain generated during a forming operation in a blank and in turn prevent the formation of cracks at the center of an arc part, which strength flanging method performs stretch flanging using a stretch flanging tool provided with a top surface part having a protruding part in a top view, straight wall parts, a main slanted wall part between the top surface part and the straight wall parts positioned forming an angle with the top surface part of more than 0&#xb0; and less than 90&#xb0; and with the straight wall parts of 10&#xb0; or more and less than 90&#xb0; and having two intersecting ridgelines at the straight wall part sides, a first sub slanted wall part sharing one ridgeline among the two ridgelines with the main slanted wall part and positioned forming angles with the top surface part and a straight wall part of more than 0&#xb0; and less than 90&#xb0;, and a second sub slanted wall part sharing the other ridgeline among the two ridgelines with the main slanted wall part and positioned forming angles with the top surface part and a straight wall part of more than 0&#xb0; and less than 90&#xb0;.

Stretch flanging tool, stretch flanging method using the same, and member with stretch flange

This manufacturing method of a structural member includes an intermediate step and a bending step. A height difference is provided on a bottom wall of a groove part between an intermediate position and both end positions sandwiching the intermediate position therebetween in a longitudinal sectional view in an extending direction of the groove part by the pressing in the intermediate step, and thereby at least one of a first curved part which has a concave curved shape in a plan view and a convex curved shape in the longitudinal sectional view and a second curved part which has a convex curved shape in the plan view and a concave curved shape in the longitudinal sectional view is formed on the bottom wall.

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Tokyo, Japan

Ryo Tabata