Press-forming mold designing method and press-forming mold,申请号US201214368062-传众专利搜索

Press-forming mold designing method and press-forming mold

申请公布号：US9333549(B2)

申请号：US201214368062

申请日期：2012.12.18

申请公布日期：2016.05.10

申请人：

JFE STEEL CORPORATION

发明人：Fujii Yusuke;Shinmiya Toyohisa;Yamasaki Yuji;Higai Kazuhiko

分类号：B21D22/02;B21D37/20;B30B15/02;B30B12/00;B21J13/02

主分类号：B21D22/02

代理机构：

Oliff PLC

代理人：Oliff PLC

地址：Tokyo JP

摘要：A prediction equation “R0/t≧(2R/t+(2R/t+1)εf)/2(1−(1+2R/t)εf)” is derived which predicts that bendability-dominated fracture will not occur when the critical surface strain εcritical is not exceeded by a strain on the metal sheet surface causing the occurrence of ductility-dominated fracture that is obtained from the minimum curvature radius R0 of a press-forming mold and the critical strain εf in a plane strain region in a forming limit diagram. The minimum curvature radius R0 of a mold required to prevent the occurrence of bendability-dominated fracture is estimated, and the mold is designed with a curvature radius that is not less than the curvature radius R0.

主权项：1. A press-forming mold designing method comprising: providing a metal sheet workpiece having a sheet thickness t; determining a minimum curvature radius R0 of a press-forming mold surface, the minimum curvature radius R0 satisfying the following equation: R0/t≧(2R/t+(2R/t+1)εf)/2(1−(1+2R/t)εf)wherein:εf is a critical strain for the occurrence of fracture in a plane strain region of an outwardly bent side of the metal sheet workpiece, andR is a critical bending radius defined as a minimum bending radius allowing the metal sheet workpiece to be bent without the occurrence of fracture on an outwardly bent surface of the metal sheet workpiece; and fabricating a press-forming mold having a punch, wherein a surface of the punch that is configured to contact the metal sheet workpiece does not have any portion with a radius of curvature less than the minimum curvature radius R0.