Patent ID: 11904374
Assignee: NIPPON STEEL CORPORATION
Field: Machine tools (Mechanical engineering)
Classification: CPC B | IPC B

Claim 2:
3. A method for producing a blank comprising:
a sheared edge comprising, in a sheet thickness direction, a sheared surface and a fractured surface, wherein
the sheared edge has a loop shape in plan view,
the sheared edge has an edge comprising, in plan view, a curved portion that is concavely curved, and
an average of lengths of the fractured surface in the sheet thickness direction in the curved portion is greater than an average of lengths of the fractured surface in the sheet thickness direction over an entire perimeter of the sheared edge, the method using the die assembly according to claim 1, the method comprising the steps of:
placing a metal sheet on the die of the die assembly, and
shearing the metal sheet on the die using the punch of the die assembly,
wherein, in the step of shearing, at least a portion of the curved portion of the blank is formed by cutting a portion of the metal sheet via the cutout portion of the punch.