Patent attributes
A press forming method which can prevent a stretch-flange crack while using conventional press forming equipment at a time of press forming a formed member with flange includes steps of constructing a blank for press forming with a base body blank portion corresponding to flat base body of the formed member, and a concave flange blank portion formed by bending on a concave outer peripheral edge of the base body blank portion. The concave blank portion is constituted by a convex flange blank portion in which a stretch-flange deformation is generated, and an adjacent flange blank portion which is adjacent thereto. An outer peripheral edge of the convex flange blank portion is formed such that one end exists between two points on a profile line corresponding to an outer peripheral edge of the adjacent flange blank portion, the other end exists between two other points, and the one end and the other end are smoothly connected between the straight lines.
