Birch, Stewart, Kolasch & Birch, LLP
Method for shear processing
The present invention provides a method for shear processing whereby a sheared surface having a small residual stress and excellent surface properties is formed and the service life of a punch is prolonged in a shear processing for shearing, by a shear line that crosses a weld zone, a workpiece with a large thickness of level difference of a weld zone and/or obtained by welding together a steel sheet having a strength of 1000 MPa or more and another steel sheet. The shearing for shear processing method according to the present invention is a method for shearing a workpiece having a weld zone using a punch and a die, the method characterized in that two protrusions are provided to a cutting edge of the punch, all or part of the weld zone of the workpiece is flanked from the two sides by the two protrusions, and the workpiece is sheared by a shear line that crosses the weld zone.
NIPPON STEEL CORPORATION
B B B B B
B23D B21D B23D B23D B21D
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Takashi Masahiro Shigeru Tohru
Yasutomi Saito Yonemura Yoshida