公开(公告)号：US20200292429A1

公开(公告)日：2020-09-17

申请号：US16640224

申请日：2018-07-13

Applicant: JFE Steel Corporation

Inventor： Yusuke Fujii ,  Kento Fujii ,  Yuji Yamasaki

IPC: G01N3/28 ,  B21D5/00 ,  G06F30/17 ,  G06F30/23

Abstract: There are provided an evaluation method and a prediction method for a and a technology to be reflected in a press die designing method. A deformation limit evaluation method includes evaluating the deformation limit on a sheared surface of a metal sheet in press-forming the sheared metal sheet. The deformation limit is evaluated and a crack in the sheared surface is predicted based on the relationship between an index value determined from two surface strain distribution gradients of a surface strain distribution gradient in a sheet thickness direction in the sheared surface and a surface strain distribution gradient in a bending ridge line direction by bending in a direction away from the sheared surface at an evaluation position among distributions of strains generated near the boundary between a bending outside surface and the sheared surface of the metal sheet to be bent and a tension generated in the sheared surface.

公开(公告)号：US11971390B2

公开(公告)日：2024-04-30

申请号：US17438302

申请日：2020-03-13

Applicant: JFE STEEL CORPORATION

Inventor： Kento Fujii ,  Toyohisa Shinmiya ,  Yuji Yamasaki

IPC: G01N3/08 ,  B21D22/00 ,  B21D22/02 ,  G06F30/20 ,  G06F30/23

CPC classification number: G01N3/08 ,  B21D22/00 ,  B21D22/02 ,  G06F30/20 ,  G06F30/23 ,  G01N2203/0017 ,  G01N2203/0062 ,  G01N2203/0075 ,  G01N2203/0214 ,  G01N2203/027

Abstract: A method includes two or more reference strain gradient information being a relationship between the strain at the hole edge and a strain gradient along a radial direction. Hole expansion forming is performed on the evaluation metal sheet under the same forming conditions as respective forming conditions corresponding to at least two pieces of the reference strain gradient information to obtain at least two limit hole expansion ratios at a hole expansion limit of the evaluation metal sheet. A formable region of the evaluation metal sheet is obtained from the at least two pieces of the reference strain gradient information and the obtained at least two limit hole expansion ratios at the hole expansion limit. Stretch flange cracking at the sheared end face of the evaluation metal sheet is evaluated by the obtained formable region.

公开(公告)号：US11609166B2

公开(公告)日：2023-03-21

申请号：US16640224

申请日：2018-07-13

Applicant: JFE Steel Corporation

Inventor： Yusuke Fujii ,  Kento Fujii ,  Yuji Yamasaki

IPC: G01N3/28 ,  G06F30/23 ,  G06F30/17 ,  B21D5/00

Abstract: There are provided an evaluation method and a prediction method for a technology to be reflected in a press die designing method. A deformation limit evaluation method includes evaluating the deformation limit on a sheared surface of a metal sheet in press-forming the sheared metal sheet. The deformation limit is evaluated and a crack in the sheared surface is predicted based on the relationship between an index value determined from two surface strain distribution gradients of a surface strain distribution gradient in a sheet thickness direction in the sheared surface and a surface strain distribution gradient in a bending ridge line direction by bending in a direction away from the sheared surface at an evaluation position among distributions of strains generated near the boundary between a bending outside surface and the sheared surface of the metal sheet to be bent and a tension generated in the sheared surface.

公开(公告)号：US12017265B2

公开(公告)日：2024-06-25

申请号：US17433375

申请日：2019-12-19

Applicant: JFE STEEL CORPORATION

Inventor： Kento Fujii ,  Yuji Yamasaki

IPC: B21D24/16 ,  G01N3/20 ,  G01N3/28

CPC classification number: B21D24/16 ,  G01N3/20 ,  G01N3/28 ,  G01N2203/0066 ,  G01N2203/0218 ,  G01N2203/0246 ,  G01N2203/027

Abstract: A technology for evaluating forming allowance for a bending crack at a sheared end face of the press-formed component from shape information of an actual component. The method includes applying press forming including bending deformation to a metal sheet being sheared to manufacture a press-formed component, evaluating forming allowance for a bending crack at a sheared end face being an end face subjected to the shearing. A crack index value for evaluating the bending crack at the sheared end face of the press-formed component is obtained from a bend outer side strain at or near the sheared end face acquired on a basis of a component shape of the press-formed component and a press die bend radius at a portion forming the sheared end face in a press die used in the press forming, and the forming allowance for the bending crack is evaluated by the obtained crack index value.

公开(公告)号：US11590591B2

公开(公告)日：2023-02-28

申请号：US16649866

申请日：2018-08-02

Applicant: JFE STEEL CORPORATION

Inventor： Kento Fujii ,  Yusuke Fujii ,  Yuji Yamasaki

IPC: G01N3/28 ,  G01N3/24 ,  B23D15/06

Abstract: To prevent a crack from occurring on a sheared end face due to press forming, a technology is provided for evaluating and predicting a crack limit of the sheared end face of a metal sheet and determining press forming conditions. In a deformation limit evaluation method for, when deforming by press forming a metal sheet subjected to shearing, evaluating a deformation limit of the sheared end face of the metal sheet, the deformation limit is evaluated by an index value obtained from two stress gradients at an evaluation position among stress distributions occurring in the vicinity of the sheared end face of the metal sheet due to the press forming, which gradients are a stress gradient in a sheet thickness direction and a stress gradient in a direction away from the sheared end face.