Patents Assigned to JTE Steel Corporation
  • Publication number: 20100071434
    Abstract: A press forming method for a metal sheet is provided. The method is capable of improving a forming limit at which a crack appears in a metal sheet and being easily applied to a large press machine for mass production with a low cost, without correcting the shape of dies, such as a punch and an upper die, or changing the shape or material of a blank to a special shape or material. Dies, a surface roughness of which is an arithmetical mean roughness Ra of 7.5 ?m or smaller, are used as a punch, an upper die, and a blank holder. Fluid with a kinematic viscosity of 500 mm2/s of lower (40° C.) is used as a lubricant, and is supplied to a space between a metal sheet and the blank holder, a space between the metal sheet and the punch, and a space between the metal sheet and the upper die. A die is detached from a workpiece in the middle of forming, and resuming the forming, thereby improving formability.
    Type: Application
    Filed: January 22, 2007
    Publication date: March 25, 2010
    Applicant: JTE Steel Corporation
    Inventors: Yoshikiyo Tamai, Yuji Yamasaki, Akihide Yoshitake