Patent ID: 10022764

Abstract:
In a press forming step of obtaining, from a blank of high-tensile strength steel sheet of 390 MPa or more, a press-formed product with a shape of cross section having a groove bottom part, ridge line parts, and vertical wall parts. An outward flange including parts along the ridge line parts is formed at an end part in a longitudinal direction. Forming parts to the ridge line parts is started by creating a region positioned at an end portion, in a longitudinal direction, of a part to be formed to the groove bottom part of the blank, which is separated from a punch top part. At that time or thereafter, the region is made to approach the punch top part. When forming the ridge line parts, forming of the parts of the outward flange are conducted, the parts are formed from the start to the middle of the press forming, to reduce or prevent an occurrence of stretch flange fracture and a generation of wrinkling