Nippon Steel Corporation

Akira Egami

Takashi Matsuno

Masahiro Saito

Shigeru Yonemura

Yasunori Sawa

Kohki Nakamura

A sheet-shaped blank () for press forming is produced by shearing a metal sheet (). The blank () includes a sheared edge (), which includes a sheared surface () and a fractured surface () in the sheet thickness direction and has a loop shape in plan view. In plan view, an edge of the sheared edge () includes concavely curved portions (). The average of lengths of the fractured surface () in the sheet thickness direction in the curved portions () is greater than the average of lengths of the fractured surface () in the sheet thickness direction over the entire perimeter of the sheared edge ().

Blank, formed article, die assembly, and method for producing blank

In a method for producing an outer panel having a character line, a punch includes a projecting portion for forming a bent surface of the character line at a punch top portion, and a punch shoulder R portion. A contact pressure applied to a blank by at least one of the projecting portion and the punch shoulder R portion is higher than a contact pressure applied to the blank by a remaining portion of the punch which excludes the projecting portion and the punch shoulder R portion. A static friction coefficient of a first portion of the punch which includes at least one of the projecting portion and the punch shoulder R portion with respect to the blank is larger than a static friction coefficient of a second portion of the punch which excludes the first portion with respect to the blank.

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Tokyo, Japan

Akira Egami